# Concrete Footings for a Detached Garage???



## vsheetz

I poured a monolithic slab for my 24x30 workshop/garage in SoCal. No sill wall. Footing is ~12-18" wide and ~18-24" deep.


----------



## Daniel Holzman

I am not sure what you mean by a sill wall. The foundation wall is usually called a frost wall in New England, however in other parts of the country a slab is often placed with a turned down edge which might be as little as 12 or 18 inches deep. The other design, specifically a footing with a stem wall, is generally used for the basement, not often used for a detached garage.

As for the pour, well you can pour the entire combination of footing, wall and slab monolithically if you choose, but more often the slab is poured separately, since the slab for a garage typically has no structural function, it is just there to provide a suitable surface to park your car on. The slab is normally designed with crack control joints, and in my experience is usually not tied to the frost wall at all.


----------



## vsheetz

Depicted below is a monolithic slab - and is how my slab in the pictures was poured. I have done both monolithic slabs and stem walls with the floor poured inside the stem walls.

I think what the OP is referring to as a sill wall would be the portion of a stem wall construct that would extend above the garage floor level - and the walls are built upon (OP, please correct me if am wrong). I have never seen a monolithic slab with an integrated "sill" wall, but I guess it could be done with the appropriate form work.

A height advantage can be had using the stem wall construction - in that the walls are thus higher from sitting on the stem wall and allowing more overall overhead clearance and room for a taller garage door. With 8' and taller garage doors becoming more the norm this can be a factor. Of course wood framed 9' or taller walls could be erected on a monolithic slab to accomplish this.


----------



## jomama45

vsheetz said:


> I think what the OP is referring to as a sill wall would be the portion of a stem wall construct that would extend above the garage floor level - and the walls are built upon (OP, please correct me if am wrong). I have never seen a monolithic slab with an integrated "sill" wall, but I guess it could be done with the appropriate form work.


 
Most every garage slab we do has a concrete curb poured with the slab for two main reasons: It keeps the plate higher & away from potential water & allows the slab to be pitched to the OH doors while the curb is tapered to allow the wall to be built on a level surface. It does involve mor ecomplex forming & finishing, but it's still fairly easy to do. I believe this was covered a while ago, a few pics may even be in that thread.

BTW vsheetz, is that colored concrete or is it just decieving in the pic where your pouring it?


----------



## vsheetz

jomama45 said:


> BTW vsheetz, is that colored concrete or is it just decieving in the pic where your pouring it?


Good eye - yes, a terra cotta coloring in the concrete. :thumbsup:


----------



## canyonbc

vsheetz said:


> Depicted below is a monolithic slab - and is how my slab in the pictures was poured. I have done both monolithic slabs and stem walls with the floor poured inside the stem walls.
> 
> I think what the OP is referring to as a sill wall would be the portion of a stem wall construct that would extend above the garage floor level - and the walls are built upon (OP, please correct me if am wrong). I have never seen a monolithic slab with an integrated "sill" wall, but I guess it could be done with the appropriate form work.
> 
> A height advantage can be had using the stem wall construction - in that the walls are thus higher from sitting on the stem wall and allowing more overall overhead clearance and room for a taller garage door. With 8' and taller garage doors becoming more the norm this can be a factor. Of course wood framed 9' or taller walls could be erected on a monolithic slab to accomplish this.



That is exactly what I am talking about the short wall that extends higher then the garage floor.

It sounds like by this post and others that there is a way to form up the wall to achieve this with a monolithic poor. 

Does anyone have some suggestions on how to this, maybe another thread where it has been discussed? Diagram anyone have to share???

My main question, is when you make a curb with a monolithic poor how do you support or hold up the form board of the curb on the slab side. 

Do you put a stake in and then remove it once the curb has set up a little bit? - If so how would you really know it has set up enough to achieve that. 

Can you build the form board up, screw it together and do not need a stake on the slab side because it is not enough weight???

Thanks all again for the advice??


----------



## jlhaslip

Slab dimensions we use around here:










Rebar mat in the middle of the slab extends to within an inch of the outer perimeter. Two bars centred in the thickened footing and a single bar in the curb. Add Fibermesh and you should be good to go.

Typicial method for hanging the inside form without pins to support it.

Notice that for the drawing purposes that the gusset is shown at the top of the curb. Leave enough space there to slip a trowel under it. Anchor bolts are placed as per usual layout for your area, although you might want to use longer ones so they sit down into the footing at the thickened edge.


----------



## canyonbc

jlhaslip said:


> Slab dimensions we use around here:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Rebar mat in the middle of the slab extends to within an inch of the outer perimeter. Two bars centred in the thickened footing and a single bar in the curb. Add Fibermesh and you should be good to go.
> 
> Typicial method for hanging the inside form without pins to support it.
> 
> Notice that for the drawing purposes that the gusset is shown at the top of the curb. Leave enough space there to slip a trowel under it. Anchor bolts are placed as per usual layout for your area, although you might want to use longer ones so they sit down into the footing at the thickened edge.


Thank you so much for the drawing, I am printing it out and going in my notes. 

great design, I see you have the plywood guesset on the back side and I assume you use gussets on top of the 2 x material to hold it together. 

I like the angled design so you can get a trowel in there to finish as normal. 

You have never had problems with the 2 x material that is cut an angle ever pushing out towards the slab? with not takes or anything holding it up???

Thanks again,
Mike


----------



## Thurman

The concrete for my 24' x 36' shop was poured in '96 and the concrete man used the form which "jlhaslip" has shown. He used bolts to hold the forms in place for the 6" high wall he was pouring on mine, with the bolt being easily removed after the pour had set most of the day. I asked for this at the time as I had plans to just "wash out" my garage floor with a garden hose. Well, after it became more of a "storage building" for my wife and son :yes: I haven't washed it out since. As a matter of fact, I haven't been able to use it for it's intended purpose much. If anyone come up with a design for a garage/shop which will deter family members from using it as a storage building--please advise me of these plans. Thanks, David


----------



## jlhaslip

Nope. 

Make them out of 3/4 ply and leave about 6 inches of meat on the top and sides seems to work. Place one about every 3 or 4 feet on the outside wall. If in doubt, or using plywood for the inside form, add extras and reduce the spacing of them. 

Use 2 x 2's to nail them to the inner/outer forms.

You can also look at additional support by using blocks across the top of the 2 x material.

As for bulging and wall deformation, that is why the wall is 5" wide only. With 1/2 " ply outside and 1/2" drywall inside of a 2 x 6 frame wall, the concrete can move a little and the wall can still sit where it needs to. 

Of course, we don't need any earthquake or termite protection around here, so I am not familiar with any implications those conditions might bring into the equation.

I've built 30 ' x 40 ' shop slabs using this method and it was all good.


----------



## jlhaslip

> If anyone come up with a design for a garage/shop which will deter family members from using it as a storage building--please advise me of these plans.


Hang an overhead door on the thing, but don't wind the springs. Works for me.


----------



## canyonbc

jlhaslip said:


> Nope.
> 
> Make them out of 3/4 ply and leave about 6 inches of meat on the top and sides seems to work. Place one about every 3 or 4 feet on the outside wall. If in doubt, or using plywood for the inside form, add extras and reduce the spacing of them.
> 
> Use 2 x 2's to nail them to the inner/outer forms.
> 
> You can also look at additional support by using blocks across the top of the 2 x material.
> 
> As for bulging and wall deformation, that is why the wall is 5" wide only. With 1/2 " ply outside and 1/2" drywall inside of a 2 x 6 frame wall, the concrete can move a little and the wall can still sit where it needs to.
> 
> Of course, we don't need any earthquake or termite protection around here, so I am not familiar with any implications those conditions might bring into the equation.
> 
> I've built 30 ' x 40 ' shop slabs using this method and it was all good.


Great thanks again for the advice. I am excited to give it a shot. I will keep everyone informed once the project starts....Gonna be a while though I think at this point


----------



## canyonbc

jlhaslip said:


> Hang an overhead door on the thing, but don't wind the springs. Works for me.


Haha...I will second this.


----------



## Willie T

Everyone new to concrete work thinks 'monolithic'. Be smart, and break this rather overwhelming (for a beginner) task into several stages. You will be glad if you do... and you will regret it if you don't.

The 'exploded' picture shows the most realistic way to tackle the job.

BTW...... Keep ALL rebar at least 2" away from the forms and the edges of the slab.... everywhere.


----------



## canyonbc

Willie T said:


> Everyone new to concrete work thinks 'monolithic'. Be smart, and break this rather overwhelming (for a beginner) task into several stages. You will be glad if you do... and you will regret it if you don't.
> 
> The 'exploded' picture shows the most realistic way to tackle the job.
> 
> BTW...... Keep ALL rebar at least 2" away from the forms and the edges of the slab.... everywhere.


Good Point. 

I am not sure yet, but realistically I am going to build the forms with a couple buddies and the finish work I will sub out.

In your experience and some one with out a ton of skill in concrete that if I were to sub out the finish work of the monolthically filled foundation that a novious can handle the 16 x 20 garage.

or 

would you still recommend breaking it up. 

If you break it up would you do the foundation and sill wall in one shot and the slab in another or break it up into three parts???'

Thanks
Mike


----------



## Willie T

Doing the footing is not rocket science, and it requires no real skill. Basically, you dig a clean trench, install the rebar on wire 'chairs', and then pour it to a specific level. I can't tell you the thousands of feet of footings I've done by simply dragging and wiggling the backside of a flat shovel along like a boat.

The wall is next. You probably would want to hire a mason and a helper to do this for you. It needs to be straight, level, and smooth. Difficult for a novice to do.

You can install all the expansion joint yourself in a few hours. It simply nails into the wall with 'stub' nails.

You can also pour the wall yourself. No biggie here at all. Just order 'grout' mix, and not regular concrete for this. (That's important... they set up and cure differently)

Yes, by all means have a pro do your slab pouring and finishing..... although you can handle the slab prep yourself.

That's all there is to it. Of course you will have to learn the proper and legal ways to do some of this work, but that isn't hard. And everyone here will help.

So.............. 

1.- Dig trench
2.- Install rebar
3.- Pour footing concrete
4.- Lay block wall
5.- Fill block wall with 'grout'
6.- Nail on the expansion joint
7.- Prepare the slab (include all under-slab wiring and piping)
8.- Pour & Finish the slab

There are a few exact steps to follow in doing some of the things above, but that's the outline in a nutshell.


----------



## vsheetz

Willie T said:


> Everyone new to concrete work thinks 'monolithic'. Be smart, and break this rather overwhelming (for a beginner) task into several stages. You will be glad if you do... and you will regret it if you don't.
> 
> The 'exploded' picture shows the most realistic way to tackle the job.
> 
> BTW...... Keep ALL rebar at least 2" away from the forms and the edges of the slab.... everywhere.


This is how I have done it when I need to have the walls up higher. It's not that hard - as said, just encompasses a few steps. Getting the block walls straight and well squared is a biggie - because the whole building will only be as true and straight as they are.


----------



## canyonbc

Well thanks everyone for the advice. 

A lot to think about, have a few months to think about it. 

Great advice and a few choices. 

I will take pictures once the project starts and keep things going


----------



## Willie T

May I suggest that now is the ideal time to do the most time consuming part of the job. And that is compiling and learning all the required knowledge and information. Your comment about "_I will take pictures once the project starts and keep things going_ " is a little disturbing. Why? Because that's how most novices get themselves into deep trouble.

Just as we contractors do, you should have every single step of this project (and they are ALL projects) laid out clearly in your head as well as on paper. It is often too late once you've started to get workable answers. "Should haves and Could haves" hurt both the pride and the pocket book.


----------



## canyonbc

Willie T said:


> May I suggest that now is the ideal time to do the most time consuming part of the job. And that is compiling and learning all the required knowledge and information. Your comment about "_I will take pictures once the project starts and keep things going_ " is a little disturbing. Why? Because that's how most novices get themselves into deep trouble.
> 
> Just as we contractors do, you should have every single step of this project (and they are ALL projects) laid out clearly in your head as well as on paper. It is often too late once you've started to get workable answers. "Should haves and Could haves" hurt both the pride and the pocket book.



Hey valid point and i 100% agree to with you, i was not real clear but i am taking this time to make re make and finalize a game plan and budget for the whole project. I think i am atleast 14 months out right now. What i meant but thinking was figuring out what type of foundation and panel i want. Eith the pictures i meant once i start the project i will post pictures of the progress of the garage


----------



## TitaniumVT

WillyT, 

That's a great drawing. Thanks for sharing. Does anyone know if it's drastically less expensive to build the stem wall with concrete blocks and then pouring them solid, *vs.* building forms and using poured concrete? Let's assume with a block wall, I'd build it myself, and with a poured wall, I'd hire the same guy doing the slab pour.

The former seems easier for DIY, but I'm not sure which method would yield a stronger wall and whether the cost differential makes it worth doing it myself. Thoughts?


----------



## canyonbc

TitaniumVT said:


> WillyT,
> 
> That's a great drawing. Thanks for sharing. Does anyone know if it's drastically less expensive to build the stem wall with concrete blocks and then pouring them solid, *vs.* building forms and using poured concrete? Let's assume with a block wall, I'd build it myself, and with a poured wall, I'd hire the same guy doing the slab pour.
> 
> The former seems easier for DIY, but I'm not sure which method would yield a stronger wall and whether the cost differential makes it worth doing it myself. Thoughts?


Thats a great question, I would like to add one thing on to it or one question to help expand. 

I am not a foundation expert so please work with me here, I know there are 6'' 8'' 10'' 12'' and maybe larger and there is normal weight light weight, blocks for bond beams with rebar some use mesh between the rows. 

I feel pretty confident to assume that there is different in how much weight each can handle and also the shear strength of each block. 

For my situation, I am building a 16 x 20 garage but would it be different for a larger garage or a basement on a house or a basement with a two story house on top. 

What I am getting at, is how do you know when to expand and to make TitaniumVT question more specific can you relate it to a 16 x 20 garage?

thanks,
mike


----------



## Willie T

Stay cognizant of the fact that lightweight blocks should not even be considered when you are contemplating placing the load of an entire structure upon them. Use regular concrete blocks.

Next, concrete isn't cheap. And you are anticipating filling the entire 8" width of that 'formed' wall with the stuff. Filling only the cells in a block wall will require much less grout. (and 'grout' mix may be cheaper... I'm not sure) You could fill that block wall I drew in post #15 with only 3/4 of a cubic yard of grout... It would take about twice that much concrete to fill a wooden form of the same size.

Now you come to the cost difference in nothing but some blocks and mortar to make a wall, compared to buying, cutting, and fitting all the necessary 3/4" plywood, 2x4's, and nails for the necessary formwork to make a solid concrete wall. Remember, you're doing two sides to this formwork. Then, of course, you do have to know a fair amount of exactly how those forms are to be constructed. 3/4 plywood ain't cheap, and it's going to take a heap of 2x4's for "whalers" or more correctly, '_wailers_', (lateral reinforcement), stiff backs, (vertical reinforcement), and diagonal bracing and anchor stakes to keep the formwork straight and plumb. Then you have the cost of "spreader ties" to keep the internal size of the form consistent to be considered. Formed walls also require more rebar than filled block walls.

Blocks ARE a 'form' in themselves. And all you do is pour them full of grout. No plywood, no bracing, no disassembly of the form afterward (you should not leave the wood in there) I honestly would recommend blocks as the better way to go for a simple structure like a garage.

Strength: I've built several hundred two-story houses on block foundation walls. Although only a few that way with basements. We really do very few basements here in Florida.


----------



## canyonbc

Willie T said:


> Stay cognizant of the fact that lightweight blocks should not even be considered when you are contemplating placing the load of an entire structure upon them. Use regular concrete blocks.
> 
> Next, concrete isn't cheap. And you are anticipating filling the entire 8" width of that 'formed' wall with the stuff. Filling only the cells in a block wall will require much less grout. (and 'grout' mix may be cheaper... I'm not sure)
> 
> Now you come to the cost difference in nothing but some blocks and mortar to make a wall, compared to buying, cutting, and fitting all the necessary 3/4" plywood, 2x4's, and nails for the necessary formwork to make a solid concrete wall. Remember, you're doing two sides to this formwork. Then, of course, you do have to know a fair amount of exactly how those forms are to be constructed. 3/4 plywood ain't cheap, and it's going to take a heap of 2x4's for "whalers" or more correctly, '_wailers_', (lateral reinforcement), stiff backs, (vertical reinforcement), and diagonal bracing and anchor stakes to keep the formwork straight and plumb. Then you have the cost of "spreader ties" to keep the internal size of the form consistent to be considered. Formed walls also require more rebar than filled block walls.
> 
> Blocks ARE a 'form' in themselves. And all you do is pour them full of grout. No plywood, no bracing, no disassembly of the form afterward (you should not leave the wood in there) I honestly would recommend blocks as the better way to go for a simple structure like a garage.
> 
> Strength: I've built several hundred two-story houses on block foundation walls. Although only a few that way with basements. We really do very few basements here in Florida.


Valid Point 

A couple questions to expand on the block foundation. 

For a 16 x 20 garage what size block would you use in Florida? 

Do you guys use "bond beams" - but my terminology may be off there but they have a slot cut out the bottom so you lay a horizontal piece of rebar or do you use the wire mesh?

Mike


----------



## Willie T

canyonbc said:


> Valid Point
> 
> A couple questions to expand on the block foundation.
> 
> For a 16 x 20 garage what size block would you use in Florida?
> *8" x 8" x 16"*
> Do you guys use "bond beams" - but my terminology may be off there but they have a slot cut out the bottom so you lay a horizontal piece of rebar or do you use the wire mesh?
> *That would only come at the top of a full wall... up where the roof starts. I'll draw you a picture of the blocks used to finish off the stem (foundation) walls.*
> Mike


 BE a few minutes on the drawing....


----------



## canyonbc

Willie T said:


> BE a few minutes on the drawing....


That would be excellent. 

Thank you in advance.


----------



## Willie T

Here is what we call a "Header Block". Other places may call it something different. A slab done this way is not the same as the purely "floating" slab shown in my previously posted drawing. This one locks into the block wall all around, and you then build on top of the slab.

The other drawing is designed to run a wall straight up past where the slab will end up. So you just butt the slab into the 'stem wall'. I prefer the way shown below.


----------



## canyonbc

Willie T said:


> Here is what we call a "Header Block". Other places may call it something different.


So this is a way to tie the slab and the block together. 

Because you have concrete on masonry do you need to put a buffer between the two like when you put a foam between sidewalk and a concrete slab? 

The other question is for this garage I would like to have a 6'' high stem wall 6'' high when doing a concrete filled wall it was going to be 6'' wide. 

Instead of using this header block do you use just a normal block up 6'' above Finished Floor? 

What program did you use to draw that? That is awesome and really detailed. 

What size block do you guys use in Florida? 

Thanks again,
Mike


----------



## Willie T

canyonbc said:


> So this is a way to tie the slab and the block together.
> 
> Because you have concrete on masonry do you need to put a buffer between the two like when you put a foam between sidewalk and a concrete slab? *No. In this case you want to 'key' (or 'lock') the slab and wall together. Often a 90 degree bent piece of rebar is sunk into the wet wall grout, and left sticking out toward the soon-to be-poured slab as a permanent TIE-IN.*
> 
> The other question is for this garage I would like to have a 6'' high stem wall 6'' high when doing a concrete filled wall it was going to be 6'' wide.
> *Not sure what you mean here. But you could easily lay 6" x 6" blocks on top to the slab after it is set up.*
> 
> Instead of using this header block do you use just a normal block up 6'' above Finished Floor?
> *Regular block anywhere BELOW the header block.* *The wall extending above the slab will be laid directly on the finished slab... any width or height or type of wall you choose.*
> 
> What program did you use to draw that? That is awesome and really detailed.
> *This is a FREE program called SKETCHUP.*
> 
> What size block do you guys use in Florida?
> *8" x 8" x 16"*
> 
> Thanks again,
> Mike


Answers are in quoted text.


----------



## Willie T

One thing to keep in mind on these little drawings is that there is normally rebar running all the way from the footing, on up through the stem wall, through the slab, on through the full height walls... right up to tie in with the bond beam at the top extent of your building walls. I'm not showing any of it because it is a pain to draw, and it clutters up the drawing.


----------



## jomama45

canyonbc said:


> That is exactly what I am talking about the short wall that extends higher then the garage floor.
> 
> It sounds like by this post and others that there is a way to form up the wall to achieve this with a monolithic poor.
> 
> Most definately. Done all the time here. You simply use 2x4 forms (plenty big for a garage this size) parellel to the outside forms @ 4-6" wide in the same direction as the slab pitches. You will also need short forms at the garage door size. No forms on the back side (side opposite the OH door), as this will be where the floor is at the same level as the walls.
> 
> Does anyone have some suggestions on how to this, maybe another thread where it has been discussed? Diagram anyone have to share???
> 
> I tried a search to no avail, but I'm fairly sure it's been discussed before along with a few diagrams.
> 
> My main question, is when you make a curb with a monolithic poor how do you support or hold up the form board of the curb on the slab side.
> 
> The way we do it is by using longer (30-36") steel stakes every 4' or so as well as 1"x2" props (~12" long so they don't split as easy) screwed between the outside form & the 2x4" curb form to prevent spreading. The stakes don't hold the greatest when it comes to spreading, but are more in place for the height.
> 
> Do you put a stake in and then remove it once the curb has set up a little bit? - If so how would you really know it has set up enough to achieve that.
> 
> :yes: Trial & error and/or experience. For a 16 x20 slab, I think if you had some help, you could handle this part. If you were to go this direction, I would suggest getting an "inside corner tool" to help finish the inside cove. The $10-15 tool can make your life much easier.
> 
> Can you build the form board up, screw it together and do not need a stake on the slab side because it is not enough weight???
> 
> We normally nail thru teh steel stakes but screw the 1x2's in place on top. Just make sure to choose slightly longer screws than necessary so that you can let the screws stick out a 1/2" as they will be less likely to get filled with concrete when pouring. A little drip of oil in the screw heads helps as well.
> 
> Thanks all again for the advice??


I'll try to explain this a little better & hopefully it makes sense:

- Set-up the exterior forms as shown in the earlier pics & sketch put up by vsheetz?

- Do all grading, compacting, placement of vapor barrier (if applicable), etc.

- Depending on if the 16' or 20' direction is going to be pitched: Use either a 16' 2x4 or scab 2- 2x4's together to acheive at least 20' long.

- Set bottom of 2x4 on top of back exterior form at back of garage.

- In the front, you have to hang the 2x4 in mid air with a steel stake. In the front, you'll want the TOP of the 2x4 level with the exterior form. This will give you 3.5" of pitch across the floor if you do it this way. By raising the 2x4 at the front of the garage, you can achieve less pitch if so desired. There is a common misconception among DIYer's that these curb forms have to be ripped down on a long angle, but that is not the case. If you do it the way I wrote, you will use the exterior form for your curb height & the BOTTOM of the curb 2x4 form as the height of the floor.

I hope that makes at least a little sense.


----------



## TitaniumVT

Willie T, you are a master with Sketchup! Thanks for all of the great insight. Two final questions from my end:

1. Is there any bracing of the blocks horizontally (i.e., anything comparable to the horizontal runs of rebar you'd use for a poured concrete stem wall)? Maybe it's not necessary. I only ask, since that support seems to be lacking with this approach

2. Would you have any concerns using blocks like these for stem walls in an earthquake zone? I live in Seattle, and while we don't get many earthquakes (the last one of any significance happened in 2001), we are technically in an earthquake area. I hardly ever see block foundations around here, but have no idea if there's a good reason for that, or if it's just that builders aren't used to this technique.

Thanks again. You guys are awesome.


----------



## canyonbc

Willie T said:


> Answers are in quoted text.


Great Information

I will be going to play with sketchup right now. 

Yes, lots of rebar especially here in California. 

Thank you for clairifiying that you do want to tie the slab and foundation together.


----------



## canyonbc

jomama45 said:


> I'll try to explain this a little better & hopefully it makes sense:
> 
> - Set-up the exterior forms as shown in the earlier pics & sketch put up by vsheetz?
> 
> - Do all grading, compacting, placement of vapor barrier (if applicable), etc.
> 
> - Depending on if the 16' or 20' direction is going to be pitched: Use either a 16' 2x4 or scab 2- 2x4's together to acheive at least 20' long.
> 
> - Set bottom of 2x4 on top of back exterior form at back of garage.
> 
> - In the front, you have to hang the 2x4 in mid air with a steel stake. In the front, you'll want the TOP of the 2x4 level with the exterior form. This will give you 3.5" of pitch across the floor if you do it this way. By raising the 2x4 at the front of the garage, you can achieve less pitch if so desired. There is a common misconception among DIYer's that these curb forms have to be ripped down on a long angle, but that is not the case. If you do it the way I wrote, you will use the exterior form for your curb height & the BOTTOM of the curb 2x4 form as the height of the floor.
> 
> I hope that makes at least a little sense.


Thanks,

I definetly think I can depict a picture from everything you wrote. 

So many ways to do the foundation, glad to take in all the information to make the best decision.


----------



## canyonbc

Going off the premise that I were to do my foundation with a 8 x 8 x 16 normal weight block, is there any tricks or calculations you guys would recommend in figuring out many blocks would be needed???


----------



## canyonbc

Sounds like it is about 113 - 8 x 8 x 16 block per 100 sq feet of wall? Can anyone confirm this.

I have also found that you want about 7.5 cubic feet or mortar per 100 blocks used - can someone confirm this too???

If i were to get the mortar bagged should I be looking at Type S Mortar in a foundation setting? 

Can anyone elaborate on what a grout mix is and why you would not use normal 2500 psi concrete???


----------



## Willie T

Right on, on the blocks. I'd say a little light on the mortar.

With grout vs concrete, it's a water content and mixture ratio thing. Concrete, as it cures, tends to actually shrink a little. This leaves you with a less than desirable tight bracing inside the blocks. Sounds nuts, but that tiny, tiny space left between the blocks and the hardened concrete core costs you a lot in reinforcing column strength. I don't know the details right off the top of my head, but I learned many years ago from commercial work that you really don't want to pour the wrong stuff in the wrong place.

Simply put, concrete loses strength when it's made soupy enough to flow as it needs to in "grouting" work. Grout, on the other hand is mixed to account for and to anticipate the water absorbing properties of masonry units (blocks), and it hardens the way it is supposed to inside block cells.

Unfortunately, most of today's concrete guys would give you a vacant stare if you asked them about this sort of thing. Kind of like the way they will also tell you "Concrete will get cracks... nuttin ya kin do about it." But ask them why the sixty year old slab in your father's garage has never cracked, and they will again get the stare. A lot of skill and quality has been lost in many of the trades over the decades. But I guess that's progress. :no:


----------



## Willie T

TitaniumVT said:


> Willie T, you are a master with Sketchup! Thanks for all of the great insight. Two final questions from my end:
> 
> 1. Is there any bracing of the blocks horizontally (i.e., anything comparable to the horizontal runs of rebar you'd use for a poured concrete stem wall)? Maybe it's not necessary. I only ask, since that support seems to be lacking with this approach
> 
> 2. Would you have any concerns using blocks like these for stem walls in an earthquake zone? I live in Seattle, and while we don't get many earthquakes (the last one of any significance happened in 2001), we are technically in an earthquake area. I hardly ever see block foundations around here, but have no idea if there's a good reason for that, or if it's just that builders aren't used to this technique.
> 
> Thanks again. You guys are awesome.


Most of this will come down to a local building department decision. They are your definitive and final answer for things structural.


----------



## Willie T

Yes, Type S is suitable for below grade work.

HERE is some good information about mortar.


----------



## canyonbc

Willie T said:


> Right on on the blocks. I'd say a little light on the mortar.
> 
> With grout vs concrete, it's a water content and mixture ratio thing. Concrete, as it cures, tends to actually shrink a little. This leaves you with a less than desirable tight bracing inside the blocks. Sounds nuts, but that tiny, tiny space left between the blocks and the hardened concrete core costs you a lot in reinforcing column strength. I don't know the details right off the top of my head, but I learned many years ago from commercial work that you really don't want to pour the wrong stuff in the wrong place.
> 
> Of course, most of today's concrete guys would give you a vacant stare if you asked them about this sort of thing. Kind of like the way they will also tell you "Concrete will get cracks... nuttin ya kin do about it." But ask them why the sixty year old slab in your father's garage has never cracked, and they will again get the stare. A lot of skill and quality has been lost in many of the trades over the decades. But I guess that's progress. :no:


Well hopefully with sights like this knowledge and I mean good knowledge can transpond through out the generations and us (younger folks) can learn. 

Thanks for the site about mortar wanted to ask one other question to ya about the block foundation, what size or dimension do you guys use down in Florida, to give some reference to what I would should be doing out here. Like you said though the building dept. of my county will be making the final call. 

Anyone else with there footing sizes too, please shoot them out.


----------



## Willie T

We usually run a 12" high by 16" wide footing for a garage like you're talking about. We go down around two to three feet because we have no frost line to worry about.

It's working on midnight here, and I still have to walk the dog.

Catch ya later.


----------



## canyonbc

Willie T said:


> We usually run a 12" high by 16" wide footing for a garage like you're talking about. We go down around two to three feet because we have no frost line to worry about.
> 
> It's working on midnight here, and I still have to walk the dog.
> 
> Catch ya later.


thanks for the knowledge, looking to keep the footings about like you described. 

enjoy walking the dog

thanks again mike


----------



## Shamus

Just a thought as I didn't see it mentioned, the height of a block wall will allow you to use 2x4x8 wall studs (if they apply in your height requirement) Vs longer studs. 

Here in the mid-west we need to go below frost line so it's footer, then block, then floor.

Willie T, Very good info. :thumbsup:


----------



## Willie T

I thought I'd introduce the first step in laying out your garage. (Well, it's actually the _third_ step, but more about that later.)

The small triangle measurements help you get the lines started in more or less the correct orientation.

The cross measurements on the large rectangle are what you will use to check for accuracy. Slight increases in one measurement will be echoed by reductions in the dimension for the other diagonal. Playing with the relative measurements is how you get the rectangle square.

And it HAS to be EXACTLY square. An eighth of an inch off is NOT acceptable.

The second picture is how you locate your "Batter Boards". These are what you will attach your string lines to for the really accurate layout.


----------



## Willie T

You are going to hear and read a lot about how you will need to go out and buy a laser level to get accurate elevations. Or at least get a "Builder's Level" (the scope on a tripod). They will say you cannot have true accuracy without them.

Neither of those statements is true.

Think about it. The Egyptians with their pyramids... The Greeks and Romans with all their aqueducts, roads and coliseums... The Mayan and Inca Indians.. and even our own forefathers... had nothing like that. They used water levels and plumb bobs. I have, too. And so can you.

In fact, though almost any of today's builders will want to dispute this, the water level is actually the most accurate of any of the tools I've mentioned.

So, unless you have too much money lying around, or just like to buy yourself new toys, you can lay out every part of this garage with those two 'old fashioned' tools, and a wooden, bubble type hand level.

CLICK HERE for a link to making and using a water level. You can GOOGLE for a lot more. I personally have a manufactured one that has a built-in sliding tape measure so I can just use math instead of moving the end of the water level up and down... but either way works equally well.


----------



## canyonbc

Willie T said:


> I thought I'd introduce the first step in laying out your garage. (Well, it's actually the _third_ step, but more about that later.)
> 
> The small triangle measurements help you get the lines started in more or less the correct orientation.
> 
> The cross measurements on the large rectangle are what you will use to check for accuracy. Slight increases in one measurement will be echoed by reductions in the dimension for the other diagonal. Playing with the relative measurements is how you get the rectangle square.
> 
> And it HAS to be EXACTLY square. An eighth of an inch off is NOT acceptable.
> 
> The second picture is how you locate your "Batter Boards". These are what you will attach your string lines to for the really accurate layout.


Thanks for the more information and the pictures to help visualize everything. 

Something we can all benefit from too.


----------



## canyonbc

Willie T said:


> You are going to hear and read a lot about how you will need to go out and buy a laser level to get accurate elevations. Or at least get a "Builder's Level" (the scope on a tripod). They will say you cannot have true accuracy without them.
> 
> Neither of those statements is true.
> 
> Think about it. The Egyptians with their pyramids... The Greeks and Romans with all their aqueducts, roads and coliseums... The Mayan and Inca Indians.. and even our own forefathers... had nothing like that. They used water levels and plumb bobs. I have, too. And so can you.
> 
> In fact, though almost any of today's builders will want to dispute this, the water level is actually the most accurate of any of the tools I've mentioned.
> 
> So, unless you have too much money lying around, or just like to buy yourself new toys, you can lay out every part of this garage with those two 'old fashioned' tools, and a wooden, bubble type hand level.
> 
> CLICK HERE for a link to making and using a water level. You can GOOGLE for a lot more. I personally have a manufactured one that has a built-in sliding tape measure so I can just use math instead of moving the end of the water level up and down... but either way works equally well.


I agree water can not lie, not matter what it will read true. 

I do have a Topcon ATG6 

Helped some family friends reside there house and two sheds from T-11 to hardie and they bought the builders level to help get the hardie lined up from the get go. At the end they gave it to me as a thank you. 

I donated my labor, nail gun and air compressor. 

I do have a water level too, all my dad and grandpa use


----------



## canyonbc

jlhaslip said:


> Slab dimensions we use around here:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Rebar mat in the middle of the slab extends to within an inch of the outer perimeter. Two bars centred in the thickened footing and a single bar in the curb. Add Fibermesh and you should be good to go.
> 
> Typicial method for hanging the inside form without pins to support it.
> 
> Notice that for the drawing purposes that the gusset is shown at the top of the curb. Leave enough space there to slip a trowel under it. Anchor bolts are placed as per usual layout for your area, although you might want to use longer ones so they sit down into the footing at the thickened edge.



Just expanding my knowledge here, 

In respects to the mono fill, on the back side where you have pointed using 2 x material. Wondering it is ok to use, has been tried and tested to use 3/4'' plywood instead of the 2 x material. 

Also wondering is it more price effective to use 3/4'' plywood on the back side??


----------



## jlhaslip

Normally 2x's are used especially on the outside. But 3/4 ply would work. Use more gussets to maintain a straight curb.


----------



## canyonbc

Makes since, in respects to the 2 x material do you like a certain size over another

i.e. a 2 x 6 over a 2x8 or 2 x 12 over a 2 x 6 as examples.


----------



## jlhaslip

canyonbc said:


> Makes since, in respects to the 2 x material do you like a certain size over another
> 
> i.e. a 2 x 6 over a 2x8 or 2 x 12 over a 2 x 6 as examples.


select a pair that matches the depth of the slab/footing combined. I use the bigger one on top so the seam is buried in the dirt after grading.


----------



## canyonbc

jlhaslip said:


> select a pair that matches the depth of the slab/footing combined. I use the bigger one on top so the seam is buried in the dirt after grading.


I like that, little thing you would not think about your first time doing it but after you would go ah, if i were to re do that i would have

well still exploring the opitions have not settled on a plan yet.


----------



## Willie T

One point I would like to interject here is that you really would be doing yourself a favor to plan now for an entry ramp where the large door will be. While the ramp can easily be poured later, the transition to the garage slab, itself, needs to be taken into consideration at this point.

The weight of a vehicle, when rolling from the ramp onto the garage slab, will eventually cause cracking across that threshold if that area is not poured deeper, and well reniforced with rebar.

Just a thought to keep in mind.


----------



## Willie T

This is not, in any way, to disparage anyone's suggestions here. The formwork as described is very good construction. In fact, I've done many similar setups myself.

However, I DO want you to be well aware of the expense and the amount of work you are signing up for with this approach. It's a LOT.

On every brace, you are going to have to have at least seven (7), possibly eight (8) pieces of wood carefully cut and accurately installed. And this is not counting the actual forms, themselves. Yes, there are some cheaper shortcuts that can save installing a few boards, but they are not examples of good, solid formwork construction. Cutting corners usually cuts quality.

And you have to transport, lift, cut, fit, plumb, level, nail, and adjust some relatively heavy and unyielding hunks of form lumber all the way around the perimeter. Again, kind of expensive stuff... and a ton of work.

By the way, those four little squares of plywood I show holding up the formboards and joining the bracket to them are pretty tough for a novice to install. (They are honestly best done if you use three longer boards instead of four short ones... see the next post below.) You may have to end up going with 2x4's there instead. And 2x4's that small tend to split when nailed. This is just something to be aware of.

And trust me, your concrete finisher is not going to think too highly of you once he gets through finishing around all those dozens and dozens of aggravating form pieces. The bottoms are nothing, but the tops can have you pulling your hair out. And they still always end up with some pretty rough looking sill top surfaces... even if you leave a half inch or so to get a trowel in there.

Then you have to strip off all the forms afterward... and pay to have the scrap pieces hauled off to the dump.

Although this is a good system, it is both quite expensive and fairly labor intensive.

One final point. No matter how you get the concrete into place (short of using a crane) you are going to have to contend with workers who really don't care too much about preserving and protecting all the work you put into getting those forms installed "just right". They will step on them, roll wheelbarrows over them, drag heavy concrete hoses over them, knock stakes out of line, and in general destroy a lot of your work.

Please think about this too... You still have to get a lot of rebar bent and tied from the slab up into a horizontal length of rebar in that little short sill wall. Without this addition, that small wall will eventually begin cracking where it meets the slab. No, bending the wire mesh up into there will not do it. It takes rebar.

DISCLAIMER: The grass and prepared slab dirt shown in these drawings will NOT be at the same height in reality. They were drawn this way simply to make visualizing the formwork easier.


----------



## Willie T

Two different ways to make that bracket.

One with 4 pieces of plywood added, the other with three longer pieces used, and the bracket made 1-1/2" wider.

The one with three longer pieces (top picture) would be much easier to make.


----------



## Willie T

Doing some more thinking. Are you planning on constructing wood walls? If so, consider 2x6 or 2x8 walls rather than 2x4's.

This thicker wall gives you unlimited area in which to make dozens of 'built-in' shelving and cabinet sections... using the studs as sides for the shelving or cabinets. It's really a smart way to go. By the time you add shelving or cabinets later, the cost is about the same. And if they are 'built-in' the wall, you don't lose any floor space.


----------



## jomama45

Willie T, first off, nice drawings! :thumbsup:

Second, I'd tend to agree that the style of forming in the pics is complicated. In fact, it's far more complicated than it needs to be. On page 1 of this thread, vsheetz's pics show just how simple this slab can be formed.

Depending on code requirements, all that would be needed would be:

2- 2x12 by 16'
2- 2x12 by 20' (or a combo to add up to 20')
3- 2x4 by whatever lengths for the curbs.
maybe 100 feet of scrap 2x3's or 2x4's for wood stakes & props.
maybe 25' of 1x2's for curb bracing.
Having a dozen or so 30-36" steel stakes or even conduit, etc would be ideal to support the inside curb form.

IMO, the plywood braces can be way too complicated for a DIY'er.

As well, one of the biggest issues I see in novice concrete forming is "over forming", meaning re-inforcing temporary forms too well. There is a fine line between overkill & practicallity, which admitadly is hard to comprehend as a DIY'er. It's always good to remember when putting every screw, nail, form, brace, etc.... into place to ask yourself: How will I get this out when removing the forms? If it involves the curb forms, it needs to be light & quick so it doesn't cut into finishign time.

Also, IF there is a pro concrete guy involved in the slab pour & finish, I would recommend A) asking him how he wants it formed or 
B) Let him form it himself the way he wan't it.

I can tell you as a pro, for a slab that size, I could form the 0-3.5" high curb adequately with one helper in less than an hour with all materials that I already carry with to every job.

PS, I REALLY AM impressed with the sketches Willie! :thumbup:


----------



## Willie T

Thanks for the compliments. But with SketchUp, it's really not that difficult.

I agree completely with the formwork being way too much for a DIY project. I still think a simple footing with a block stem wall and floating slab is the easiest way to go if there are no code restrictions disallowing it.


----------



## canyonbc

First off, I would like to thank everyone for the postings. 

A lot of great post out there.

WillieT - you are quite amazing with sketchup. 

Going along your first point of having a driveway, yes, that is being calculated into the equation, at this point the driveway will be 24' wide and 20' out. 

Around the perimeter on three sides I want to do a 4' sidewalk around the unit. Partly to make a walk way around the unit and partly to start the drainage away from the slab and building 

24' wide comes from 16' then 4' + 4' walkway on both sides

The concrete sidewalk around I will do the finish with some buddies. Have done a few sidewalks and feel I have the equipment and skill to take that task on

The driveway I will form up my self but again probably hire out the finishers

Although if the finishers can work up a bargain and do all the finishing of driveway and sidewalk maybe will do something like that. That is all up in the air at this point. 

I think I am going to go with the block because I have layed a few walls, and have a buddy who did it in the summers of high school and college. 

Thanks everyone


----------



## canyonbc

Willie T said:


> This is not, in any way, to disparage anyone's suggestions here. The formwork as described is very good construction. In fact, I've done many similar setups myself.
> 
> However, I DO want you to be well aware of the expense and the amount of work you are signing up for with this approach. It's a LOT.
> 
> On every brace, you are going to have to have at least seven (7), possibly eight (8) pieces of wood carefully cut and accurately installed. And this is not counting the actual forms, themselves. Yes, there are some cheaper shortcuts that can save installing a few boards, but they are not examples of good, solid formwork construction. Cutting corners usually cuts quality.
> 
> And you have to transport, lift, cut, fit, plumb, level, nail, and adjust some relatively heavy and unyielding hunks of form lumber all the way around the perimeter. Again, kind of expensive stuff... and a ton of work.
> 
> By the way, those four little squares of plywood I show holding up the formboards and joining the bracket to them are pretty tough for a novice to install. (They are honestly best done if you use three longer boards instead of four short ones... see the next post below.) You may have to end up going with 2x4's there instead. And 2x4's that small tend to split when nailed. This is just something to be aware of.
> 
> And trust me, your concrete finisher is not going to think too highly of you once he gets through finishing around all those dozens and dozens of aggravation form pieces. The bottoms are nothing, but the tops can have you pulling your hair out. And they still always end up with some pretty rough looking sill top surfaces... even if you leave a half inch or so to get a trowel in there.
> 
> Then you have to strip off all the forms afterward... and pay to have the scrap pieces hauled off to the dump.
> 
> Although this is a good system, it is both quite expensive and fairly labor intensive.
> 
> One final point. No matter how you get the concrete into place (short of using a crane) you are going to have to contend with workers who really don't care too much about preserving and protecting all the work you put into getting those forms installed "just right". They will step on them, roll wheelbarrows over them, drag heavy concrete hoses over them, knock stakes out of line, and in general destroy a lot of your work.
> 
> Please think about this too... You still have to get a lot of rebar bent and tied from the slab up into a horizontal length of rebar in that little short sill wall. Without this addition, that small wall will eventually begin cracking where it meets the slab. No, bending the wire mesh up into there will not do it. It takes rebar.
> 
> DISCLAIMER: The grass and prepared slab dirt shown in these drawings will NOT be at the same height in reality. They were drawn this way simply to make visualizing the formwork easier.


Willie T - I have an idea for you and will everyone. 

I have got the idea from the book Foundations and Concrete Work - by the Taunton Press - Revised edition. There is a chapter about footings and they have a picture and talk about the metal brackets they have made to go over the 2 x 12 form boards. 

What about taking this same premise and applying it to the curb, the same design you have of what looks like plywood bracing over make that steel. Two pre drilled holes can be on the one side for the 2 x 4 or 2 x 6 to brace up the curb. To take off in finishing unscrew or just pull up the entire system. 

On the back side the side that is say 24'' deep make it a few inches longer so you can hammer it in a little??

Just a thought for everyone to think about, trying to think outside the box not for my project but everyone. 

I will see if my Dad (Ironworker Local 223) can make me one and I will post the pictures 

Something to think about


----------



## canyonbc

jomama45 said:


> Willie T, first off, nice drawings! :thumbsup:
> 
> Second, I'd tend to agree that the style of forming in the pics is complicated. In fact, it's far more complicated than it needs to be. On page 1 of this thread, vsheetz's pics show just how simple this slab can be formed.
> 
> Depending on code requirements, all that would be needed would be:
> 
> 2- 2x12 by 16'
> 2- 2x12 by 20' (or a combo to add up to 20')
> 3- 2x4 by whatever lengths for the curbs.
> maybe 100 feet of scrap 2x3's or 2x4's for wood stakes & props.
> maybe 25' of 1x2's for curb bracing.
> Having a dozen or so 30-36" steel stakes or even conduit, etc would be ideal to support the inside curb form.
> 
> IMO, the plywood braces can be way too complicated for a DIY'er.
> 
> As well, one of the biggest issues I see in novice concrete forming is "over forming", meaning re-inforcing temporary forms too well. There is a fine line between overkill & practicallity, which admitadly is hard to comprehend as a DIY'er. It's always good to remember when putting every screw, nail, form, brace, etc.... into place to ask yourself: How will I get this out when removing the forms? If it involves the curb forms, it needs to be light & quick so it doesn't cut into finishign time.
> 
> Also, IF there is a pro concrete guy involved in the slab pour & finish, I would recommend A) asking him how he wants it formed or
> B) Let him form it himself the way he wan't it.
> 
> I can tell you as a pro, for a slab that size, I could form the 0-3.5" high curb adequately with one helper in less than an hour with all materials that I already carry with to every job.
> 
> PS, I REALLY AM impressed with the sketches Willie! :thumbup:


Once I choose a finisher, I will be def. communicating with him to discuss what he would like to see. 

I do need to confirm with the county that blocks are ok. 

I do believe so, I grew up in San Diego County, i have worked on and under a few homes that the sill walls were built up on block. I know live in Sonoma County and I have seen sill walls and full basements built on block. The potential garage is in El Dorado County, looking at the charts it has the same earthquake zone as Sonoma County (at least the west side of the county).

I have a phone call and a email into the building dept.


----------



## Willie T

Are you talking about something like a lintel clamp?


----------



## canyonbc

Willie T

In respects to the 2 x 6 or 2 x 8 walls - that is something I have not thought about. 

If I go 2 x 6 I can space the walls 24'' o.c. 

The reason I am apprehensive at the moment about that and most of it will come down to cost. 

The garage is being built as a garage/workspace because the permits are cheaper do not have to have plumbing or septic to the garage. 

The person who will use the garage wants to use it as a quilt room. 

Want to build it with a small sill wall and have a slope in the garage so for someone else and when they ever go to sell it will be a true garage. 

If and I am not sure a 2 x 6 wall is more money, I need to look at how much of a difference that will make when selling the house. My gut reaction is someone is not going to by a house because the 320 sq. ft garage has a 2 x 6 walls

What do you guys think?


----------



## canyonbc

Willie T said:


> Are you talking about something like a lintel clamp?


To be honest with ya, dont know what a lintel clamp is, at least I do not reconize the name.


----------



## canyonbc

To bring up the driveway, like I said in a earlier post I want to do a 24' x 20' driveway. 

I wanted to dig down 10'' and compact the soil.

We are on a mix of mainly clay with large (8'' - 24'') pieces of granite. 

Then put a layer of gravel and compact it - 6'' 

Then a 4'' slab 2500 psi

Draining away from the garage (not sure yet on the pitch)

I was going to put # 3 bars 18'' o.c. going both ways so I would have a bunch of 18'' x 18'' squares. The rebar would sit on chairs. 

Or I am thinking about 10'' x 10'' wire mesh on 2 1/2'' dolbies with rebar near the perimeter 2 - # 3 bar sitting on chairs. 

On the sides I was going to dig down 2 feet in down to six inches and this where the rebar would sit it the wire mesh

What does everyone think, open to thoughts positive and negative here to learn.


----------



## jlhaslip

#3 bar?
is that 3/8" diameter? seems light to me, but I am not where you are. We use 1/2" on 16" centers around here. or 24 o/c with mesh above it.


----------



## Willie T

jlhaslip said:


> #3 bar?
> is that 3/8" diameter? seems light to me, but I am not where you are. We use 1/2" on 16" centers around here. or 24 o/c with mesh above it.


It's a 'pencil rod + one size'. I think they call it a "Seismic tie" or something like that out in California. :huh:


----------



## canyonbc

jlhaslip said:


> #3 bar?
> is that 3/8" diameter? seems light to me, but I am not where you are. We use 1/2" on 16" centers around here. or 24 o/c with mesh above it.


Yea it is 3/8''. 

Maybe I need to bump it up to # 4 bar 16'' o.c. dont want to over do it but want to do it correct too. 

Thanks all Mike


----------



## milese

I'm getting ready to pour a slab for a 20' by 25' metal building in southern New Jersey. Do I have to go to the frost line, about 32 inches here, for a footing for a detached building? Is a floating slab an alternative?


----------



## Msradell

milese said:


> I'm getting ready to pour a slab for a 20' by 25' metal building in southern New Jersey. Do I have to go to the frost line, about 32 inches here, for a footing for a detached building? Is a floating slab an alternative?


It depends on the building codes in your community but in most cases the answer to your question would be yes you have to go down to the frost line.


----------



## jomama45

I'll have to disagree with the poster above and say that for most DETACHED structures, you will NOT need to go below the frost line. But as said, your local codes will govern this.......


----------



## Canarywood1

canyonbc said:


> To bring up the driveway, like I said in a earlier post I want to do a 24' x 20' driveway.
> 
> I wanted to dig down 10'' and compact the soil.
> 
> We are on a mix of mainly clay with large (8'' - 24'') pieces of granite.
> 
> Then put a layer of gravel and compact it - 6''
> 
> Then a 4'' slab 2500 psi
> 
> Draining away from the garage (not sure yet on the pitch)
> 
> I was going to put # 3 bars 18'' o.c. going both ways so I would have a bunch of 18'' x 18'' squares. The rebar would sit on chairs.
> 
> Or I am thinking about 10'' x 10'' wire mesh on 2 1/2'' dolbies with rebar near the perimeter 2 - # 3 bar sitting on chairs.
> 
> On the sides I was going to dig down 2 feet in down to six inches and this where the rebar would sit it the wire mesh
> 
> What does everyone think, open to thoughts positive and negative here to learn.


 
You need to bump up to at least 3000 psi for your driveway and better yet 3500psi.


----------



## jomama45

Canarywood1 said:


> You need to bump up to at least 3000 psi for your driveway and better yet 3500psi.


You do realize that's a 4 year old post.......................:whistling2:


----------



## Justcallmefinn

*foundation for 3 car garage attached*

I know this thread started out for a different reason but the high caliber of answers gives me the assurance that my questions would be answers properly.

I would like to attached a large sized two car garage to my separate guest room/office. Right now the main house and the separate guest room/office are connected by a car port. The carport and guest room/office share a mutual attic space. My driveway comes up to the carport and also extends up to one of the other sides of the guest room/office for extra parking. I wanted to put a two car garage on that part of the driveway that goes up to the other side of the guest room/office where there is the existing driveway for parking.

Do I need to remove that part of the driveway to put in the foundation or can I use the driveway as the foundation and just cut around the parameter and lay the footing. It is a one store garage but I am using trusses that will allow for a lot of stand up straight walkable attic space. One other point I want the floor to drain out the front of garage.

Thank you

JustcallmeFinn

This is my first post so I will post again the pictures


----------



## ddawg16

Justcallmefinn said:


> I know this thread started out for a different reason but the high caliber of answers gives me the assurance that my questions would be answers properly.
> 
> I would like to attached a large sized two car garage to my separate guest room/office. Right now the main house and the separate guest room/office are connected by a car port. The carport and guest room/office share a mutual attic space. My driveway comes up to the carport and also extends up to one of the other sides of the guest room/office for extra parking. I wanted to put a two car garage on that part of the driveway that goes up to the other side of the guest room/office where there is the existing driveway for parking.
> 
> Do I need to remove that part of the driveway to put in the foundation or can I use the driveway as the foundation and just cut around the parameter and lay the footing. It is a one store garage but I am using trusses that will allow for a lot of stand up straight walkable attic space. One other point I want the floor to drain out the front of garage.
> 
> Thank you
> 
> JustcallmeFinn
> 
> This is my first post so I will post again the pictures


Welcome to Justcallme.....

May I suggest you post your question in a new thread. You are more likely to get a detailed to your question.

Also...have at look at the garage build link in my signature...it might answer some of your questions and give you more.


----------



## tdixon

I am building a detached garage.
There is a perimeter block wall with the L shaped block at the top for the slab on grade to butt up against.
The block contractor only filled in the blocks that have rebar with grout.
He said that when we pour the slab the rest of the blocks fill in to put it all together.
I don't know if having the SOG connected to the wall is good? Shouldn't we want the SOG to be totally separated by expansion joint or a felt paper so the SOG has room for expansion and contraction so it won't crack?


----------

