# Basement Foundation DIY



## joed (Mar 13, 2005)

That does not sound like a good idea to me. 
Have you considered Styrofoam? They stack like Legos and then you fill them. You end up with a wall and insulation in one job.


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## AlphaPilot (Aug 6, 2012)

joed said:


> That does not sound like a good idea to me.
> Have you considered Styrofoam? They stack like Legos and then you fill them. You end up with a wall and insulation in one job.


Could you say why?

And that looks pricier :wink: ... Thing is I have heard termites love ICF around here...and that is foam, too. Thoughts?


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## jomama45 (Nov 13, 2008)

Reasons I can think of off the top of my head not to drystack block and fill with concrete:

- Footings have to be 100% exactly flat or the top of wall won't be level.
- Concrete block can vary significantly from one unit to another, but when you add 12+ courses together, it can be substantial.
- CMU are typically modular and rely on a 3/8" joint to reach 8'0". Dry-setting would result in a loss of 4.5" of height. You can make that up with a half course, but there's more material cost in doing so.
- Wall will be extremely tippy until concrete sets. A bump from the concrete truck chute could easily bring your plan tumbling down.
- Concrete would cost many times more than mortar.
- Every cell w/o rebar would be useless.
- The interior cavity in block offers a secondary envelope to stop water intrusion, if built correctly, and filling with concrete would plug this path up.
- It's simply non-conventional, and if the foundation needs to meet a local building code, it will be non-prescriptive to this style of construction, so you'll likely spend a large amount of money on engineering to get it OK'd by your building department.
- Conventional CMU construction is far too simple, recognized and customizable to not consider doing it the "right" way..........


I'm sure there's other reasons i could come up with as well. I think that you may be thinking that installing the block on a 4 corner basement is more complicated than it really is. If you're looking to save some money, I'd ask one of your construction buddy's if they have the name of a mason or 2 that could help you on the side for a few days. You do all the hard labor, they bring the skill-set........


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## Nailbags (Feb 1, 2012)

AlphaPilot said:


> Could you say why?
> 
> And that looks pricier :wink: ... Thing is I have heard termites love ICF around here...and that is foam, too. Thoughts?


Termites only eat wood. Just hire some one to do a monolithic pour. And be done with it.


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## AlphaPilot (Aug 6, 2012)

Lotta reasons not to go with drystack I see. Thanks :thumbsup:

Some of those issues could be resolved with specific blocks made for the job, at least I was told there are such a thing that are smooth.


So why drawbacks are their to a block wall with mortar compared to a single pour foundation. A block wall with mortar is something I think I could MAYBE accomplish because it doesn't require concrete forms.


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## AlphaPilot (Aug 6, 2012)

Sources on termites and my concern with the use of ICF.

http://www.amvicsystem.com/termites-and-icf-construction

http://www.nachi.org/icf-termite-inspection.htm

http://www.greenbuildingtalk.com/Forums/tabid/53/aff/4/aft/26910/afv/topic/Default.aspx

I understand termites don't eat foam. But they seem to bore through it, like the moisture caused after boring, and have it serve as a nice home for their trails and other uses.


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## joed (Mar 13, 2005)

Termites are not a concern in my area so I never considered that aspect.


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## AlphaPilot (Aug 6, 2012)

joed said:


> Termites are not a concern in my area so I never considered that aspect.


They seem to be here. It's not really just the rotten wood termites, but the subterrain type that like dirt and stay in it and tunnels. The issues are that they seem to drill through the icf that is covered in dirt, tunnel up between it and the concrete wall, through the sill plate or house wrap, through the studs, up to the trusses...munch away and you only know it after the major damage is done. Ooops, hunny why is the roof caved in on that corner? :laughing:


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## Nailbags (Feb 1, 2012)

a Monolithic pour is stronger has zero cold seams. is cheaper and quicker to do. Just hire some one to do the pour for you it will save time and hassle use min #4 rebar. run in your footing two rows on each side of number 4 and then run two runs of #4 a third of the way up from the footing then a nother two run a thrid from the top and every 18 incches run two vertical from footing to 4 inches from the top of the stem wall. have it all tied good and your foundation will last.


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## Mort (Nov 26, 2008)

Mono foundations would be nice, in theory, but usually the footing and stem walls are poured separately. With a mono, concrete can ooze out the top of the footing form if its too wet, and create a bunch of rock pockets in the stem wall if its too dry. To solve this, the first part of the load is poured dry, allowed to set for about 1/2 hour, and then wet up and poured into the wall forms. And this creates, you guessed it, a cold joint. 

So you might as well just pour them separately like everybody else does.


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## jomama45 (Nov 13, 2008)

AlphaPilot said:


> Lotta reasons not to go with drystack I see. Thanks :thumbsup:
> 
> Some of those issues could be resolved with specific blocks made for the job, at least I was told there are such a thing that are smooth.
> 
> ...


Not much for drawbacks from a DIY perspective IMPO. The only one that really comes to mind is that the wall typically needs to be a little wider than the poured wall alternative, taking up additional minimal space in the basement. There's postives to a properly constructed and re-enforced CMU foundation IMPO..............


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## RWolff (Jan 27, 2013)

AlphaPilot said:


> As a DIY I don't have access to concrete forms for the desired 8' basement walls. I was wondering about what ALL the drawbacks are to block wall foundations? I would probably not be mudding each brick unless someone convinces me it's not as bad as people say.
> 
> I was thinking of stacking them square and plumb, with staggered joints, then adding rebar in each cell and having the concrete truck come, pour in each cell, vibrate it and let it set. Is this not logical...or a good idea? What drawbacks do I have doing this over mortar brick walls, and poured concrete walls for basement foundations?
> 
> I've heard about 'dry stacking' and using some fancy chemical bonding on both outside ends of the blocks since there is no mortar to seal each block. I was curious what your opinions were on this too.



I added a small, about 9x12 modelling room on the back of my house in 2005, I hand dug down the whole space about 7 feet down, and dug for the footing which I poured with my cement mixer.
I embedded rebars in the footing and laid the first 2 courses of block on, and then filled the cavities of the blocks with concrete and tamped it down nicely, and built the rest of the block walls up, putting rebar down in the cavities and filling the cavities with cement. I also embedded long threaded rods into the top for attaching the plate, and filled all level with concrete.
The outside of the walls have plastic sheeting and 1" styrofoam board insulation.
I only needed 3 walls since the room was put in a corner between existing.
I also added a center footing and wall to run perpendicular to the joists.

I anticipated I would have 1,000# to a ton of clay stacked in a corner at any given time and wanted a good solid everything under it, so it's all a lot beefier than usual.

The block wall works fine for small projects like my room- the wall was only about 7' high and 12' long with a perpendicular wall in the middle. I had to do a similar block wall in another area- under the kitchen which never had a foundation at all, but for an 8 foot high wall or longer foundation poured concrete would be better I'm sure.

http://i.imgur.com/Hhig2WW.jpg
http://i.imgur.com/MvAlvVR.jpg

I had to add a sump pit which can be seen, as there was an old drain pipe 8 feet down that tended to collect ground water from the field, my house was built over 2 of them in 1930 and they just took the sections of pipe out, so every spring melt my basement got water. I dug 50' of the pipes up with an excavator 3 years ago when the city and county said they had no record of such pipes and it's older than 1880. Since then I had no water come in from them.
http://i.imgur.com/ealISmW.jpg

http://i.imgur.com/dXPGmPW.jpg

I've never heard of any chemical bonding dry stacking blocks, sounds like the lazy man's way to built a temporary building to me, use mortar.


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## stadry (Jun 20, 2009)

why anyone would build w/o using icf's beyond me,,, the addl cost is easily amortized be lower utility bills, stronger walls, & a MUCH more quiet home,,, w/o a doubt, our next home will be icf's from the footer to the eaves :thumbup:


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## jomama45 (Nov 13, 2008)

itsreallyconc said:


> why anyone would build w/o using icf's beyond me,,, the addl cost is easily amortized be lower utility bills, stronger walls, & a MUCH more quiet home,,, w/o a doubt, our next home will be icf's from the footer to the eaves :thumbup:


I'll bet you my left nut that you'd never re-coupe the costs of ICF in a basemtn from lower energy costs, well at least at your "elevated" age.............:laughing:

Honestly though, I'd never use an ICF foundation for myself, there's just far more cost efficicient ways to insulate, and I'm a firm believer that a large percentage of ICF walls will have early repair issues when given some time. That said, I think there are huge benefits to be gained by using ICF's above grade........


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## AlphaPilot (Aug 6, 2012)

RWolff said:


> I added a small, about 9x12 modelling room on the back of my house in 2005, I hand dug down the whole space about 7 feet down, and dug for the footing which I poured with my cement mixer.
> I embedded rebars in the footing and laid the first 2 courses of block on, and then filled the cavities of the blocks with concrete and tamped it down nicely, and built the rest of the block walls up, putting rebar down in the cavities and filling the cavities with cement. I also embedded long threaded rods into the top for attaching the plate, and filled all level with concrete.
> The outside of the walls have plastic sheeting and 1" styrofoam board insulation.
> I only needed 3 walls since the room was put in a corner between existing.
> ...



Thanks for your post, RWolff. I have some questions. That is some nice work IMO. Though the room was small, and not 'super deep' it seemed nice. Say I wanted 7' ceiling in basement, I would need my sheetrock up 7' but I also need to account for duct work and floor joists. So technically...I'd be at least 8' basement walls, assuming duct work ran parallel to my floor joists, otherwise even more than 8' if perpendicular since I wouldn't be fond of notching out room.

I think that would mean 6' underground, then maybe 2' above grade. It seems most basements are like that, yeah?

My footings would be 6' below grade. I think I could build my own wall, using the technique RWolff did. I am curious about single runs of rebar instead of ones every two blocks. Would a sill plate be anchored properly if I have rebar or carriage bolts ~1.2 feet in cement? 


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@itsreallyconc - I dunno, the reason I have was given earlier about termites, plus the technology is fairly new. I have seen solid pour concrete and concrete block foundations that are many..many years old. :yes: Old foundation methods with what appears to be similar sized stones and clay between have problems I know. And even old concrete block ones may. I think today with the option of a rubber external coating, and/or a sealed install of wrap would solve those issues.

----

@jomama45 - I don't see all of the energy efficiency gain when there is already earth around basement walls. I know it saves on other insulation methods, but it really is not a hassle to use rigid foam down the road when you can afford it to insulate walls. :thumbup:


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## jomama45 (Nov 13, 2008)

ANchor bolts should be covered by code, but typically, it's something like this: 1/2" anchor bolts on 6' max. centers, no more than 18" of the corners, and no less than 2 per wall. They need to be imbedded 7" into the block/concrete/grout. This usually means you need 1/2" by 10" hot-dipped galvanized bolts.


IMO, stick with 96" wall height as a minimum, you won't regret it. The beam, whether it be wood or steel will also hang below the floor joists, likely lower than any heat trunks.

You don't need 1/2" rebar at 32" centers, you'd be far better off using 3/4" rod every 4' or so, and sticking the anchor bolts in the grouted cells. Your code could certainly have all the info you would need on pilaster sizing and spacing as well .As for the grout, it's ideal to have a small stone "concrete" that's relatively weak and extremely wet (think soupy) when placed. This is one place where stronger certainly isn't better.


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## AlphaPilot (Aug 6, 2012)

I spoke with a trusted concrete contractor / mason, and got an estimate for a 34' x 36' basement, 8' tall, 2 standard window bucks, and 2 egress window bucks, he does block only, no excavation or water plumbing figured...he guessed around 24,000. That is more than I had ever figured. I gave him dimensions a bit bigger than what my floor plan is for, just to account for inflation and price of labor going up... 

I think I want to really learn how to lay concrete block and do my own foundation. Even if the idea is far fetched, if I can save 16-18 grand...I think it is worth every bit of hassle.

For Jomama...or someone who has worked with block : Why is the 10" easier to work with? Just because there is more real estate for mortar or something else that I am missing? When working on the dimension of the house, would I kill myself for going 34 x 36 rather than the initial smaller house of 32 x 34...it would be an extra 64 square feet of block...I certainly don't think that'd be too noticeable after doing the previous 1056 square feet of walls?


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## stadry (Jun 20, 2009)

by FAR, we see more leaking bsmts & repair issue w/block bsmt walls tha conc,,, what you save now WILL be repaid w/MUCH interest :laughing:

IF you want to learn how to lay block, go work for free under as a mason's apprentice :thumbsup: im-n-s-h-fo, you won't even know what errors you make til its too late down the road,,, too often one's romanticism overweighs logical thought & economic sense


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## concretemasonry (Oct 10, 2006)

AlphaPilot -

The 10" wall thickness in WI is a local and traditional throw-back from the the amount of block machines could make per cycle that were commonly used in WI years ago that could not make 12" two at a time, so the labor and investment made a wider block much more expensive, so the tradition started. That was before people recognized that masonry was based on a 4" moulse dimension thta worked with other materials (ever seen a 40" sheet of a wood panel or studs at 10" or 20" on center?). Now, 8" foundation walls are also promoted because they can be as strong as 8" poured wall ans 10" masonry walls are not really cheaper than 12" walls.

The 10" dimension does not work with any details today because it is old and is like swimming upstream. - Just look at corner details.

All my relatives are from WI, so this is just personal experiences from relatives in construction and supplying materials in WI.

Dick


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## stadry (Jun 20, 2009)

,,, ' 8" foundation walls are also promoted because they *can* be as strong as 8" poured wall ' ? ? ? :huh: cmu walls _*can*_ be as strong as poured conc :huh: ? ? ? pardon ? by far, we see many more problems w/block walls than conc but that's probably because they were laid back in the day :yes: what say you, dick ?


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## jomama45 (Nov 13, 2008)

AlphaPilot said:


> I spoke with a trusted concrete contractor / mason, and got an estimate for a 34' x 36' basement, 8' tall, 2 standard window bucks, and 2 egress window bucks, he does block only, no excavation or water plumbing figured...he guessed around 24,000. That is more than I had ever figured. I gave him dimensions a bit bigger than what my floor plan is for, just to account for inflation and price of labor going up...
> 
> I think I want to really learn how to lay concrete block and do my own foundation. Even if the idea is far fetched, if I can save 16-18 grand...I think it is worth every bit of hassle.
> 
> For Jomama...or someone who has worked with block : Why is the 10" easier to work with? Just because there is more real estate for mortar or something else that I am missing? When working on the dimension of the house, would I kill myself for going 34 x 36 rather than the initial smaller house of 32 x 34...it would be an extra 64 square feet of block...I certainly don't think that'd be too noticeable after doing the previous 1056 square feet of walls?


That's an insane amount of money for such an elementary basement in "THESE" parts. 

As for the 10" block, It's far easier to keep them from tipping, especially for a DIY'er. Also, you can get away with less grouted pilasters, which will save money and time.........



concretemasonry said:


> AlphaPilot -
> 
> The 10" wall thickness in WI is a local and traditional throw-back from the the amount of block machines could make per cycle that were commonly used in WI years ago that could not make 12" two at a time, so the labor and investment made a wider block much more expensive, so the tradition started. That was before people recognized that masonry was based on a 4" moulse dimension thta worked with other materials (ever seen a 40" sheet of a wood panel or studs at 10" or 20" on center?). Now, 8" foundation walls are also promoted because they can be as strong as 8" poured wall ans 10" masonry walls are not really cheaper than 12" walls.
> 
> ...


Actually Dick, the vast majority if the block I lay on foundations/additions are 12", but most of them we do are 13+ course "castles". I only suggested 10" to Alpha because I don't know the soil type, and he made it sound like there would only be about 6' of foundation in the ground.

Perhap's I'll have to look up some of your kin-folk some day and see if they'd like to go out for mustriepen........:thumbsup:

BTW, the block machines are slowly dying here in WI, shapes and sizes are quickly becoming extinct. I may have to join the poured wall guys soon, or find another career.............:whistling2:



itsreallyconc said:


> ,,, ' 8" foundation walls are also promoted because they *can* be as strong as 8" poured wall ' ? ? ? :huh: cmu walls _*can*_ be as strong as poured conc :huh: ? ? ? pardon ? by far, we see many more problems w/block walls than conc but that's probably because they were laid back in the day :yes: what say you, dick ?


We tend to use twice the rebar in a CMU wall than the competitor's poured wall, which wasn't the case in the 50's, 60's 70's etc... Don't blame me for the shoddy work done back then, I wasn't even alive.......


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## AlphaPilot (Aug 6, 2012)

Pardon me, but I am a bit confused about the talk of 10" not as cheap as 12" walls. I was saying 10" wide, and asking why it was suggested. Jomama followed up with an answer though, explaining why it is better DIY.

The walls would be *6'* or possibly *6' 8"* below grade. The soil type seems to be clay, no tests done yet as to the true tech terms. I've dug in it, and what I have dug has been your general clay that is crappy for growing trees until it gets amended. (from a landscaping point).

I too figure 24,000 was _pricey_. I am guessing around 5 to 7k for materials. Including 10"W x 8"H x 16"L block @ 2.50 a piece, and just a random number for mortar, string line, and plumb bobs. Rebar around 40 cents a running foot, which I am sure that depends on the type. (*quick question* - is #5 like 5/8th of an inch and #3 3/8th of an inch when looking at code?)

I have seen various people wrinkle their nose at the idea of block over solid pour walls. :huh: I think today with the idea of one of many forms of exterior coating from waterproofing, tar paper, rubber coating, spray foam, or even rigid foam that having leaks and such is a thing of the past. Especially if one were to have a weeping tile system, right? 

So - if you found some ambitious person wanting to block their basement...what advice would you give or would you try your hardest to detour them and suggest they contract it out, or pay someone for a solid poured wall?


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## stadry (Jun 20, 2009)

you'se confused ? well, i'se ALSO confused,,, someone who don't know how to lay block want's to build their own home on TOP of block they laid about which they have to ask online forums for advice/responses/how-to's ? & that person wants to build his family's HOME on top of that foundation just because he can save a few bucks but its worth the risk to his family's safety, health, & well-being ? lateral soil pressure's the BIG reason block walls fail as their compressive strength's good enough,,, IF you want a foundation that's ' good enough ',,, reminder - ALL the house foundations we repair were BUILT TO CODE RQMTS ! ! ! any questions now ?

shirley you can see how i'se easily confused,,, even ' type of rebar ' are you thinking epoxy-coated ? usually only a rqmt in certain parts of some bdge work & hgwy load transfer devices for the avg contractor,,, i'd suggest saving $ by cutting back on the designer kitchen & knock-your-socks-off mstr bathroom than f yourself by skimping on a decent, solid, & safe home's bsmt walls,,, then again, its YOUR family & YOUR house :whistling2:


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## stadry (Jun 20, 2009)

,,, GOT IT ! A NEW IRC RESPONSE POLICY ! 
# 6: do not respond to posts that are only wile shots in the dark,,, 
# 7: remember the op's mission is to confuse & aggravate responders while ' sandbagging ' the ' REST OF THE STORY ',,,eg, i want to build my own ( insert project description & couple questions ) then, after several respond w/best advice based on op, say something like ' just wondered if my contractor ( is doing it right - trying to f' me - has no idea wtf he's doing ) :thumbup:

don't know why this never occurred previously,,,certainly would've saved lotsa headbanging :laughing:


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## AlphaPilot (Aug 6, 2012)

itsreallyconc said:


> you'se confused ? well, i'se ALSO confused,,, someone who don't know how to lay block want's to build their own home on TOP of block they laid about which they have to ask online forums for advice/responses/how-to's ? & that person wants to build his family's HOME on top of that foundation just because he can save a few bucks but its worth the risk to his family's safety, health, & well-being ? lateral soil pressure's the BIG reason block walls fail as their compressive strength's good enough,,, IF you want a foundation that's ' good enough ',,, reminder - ALL the house foundations we repair were BUILT TO CODE RQMTS ! ! ! any questions now ?
> 
> shirley you can see how i'se easily confused,,, even ' type of rebar ' are you thinking epoxy-coated ? usually only a rqmt in certain parts of some bdge work & hgwy load transfer devices for the avg contractor,,, i'd suggest saving $ by cutting back on the designer kitchen & knock-your-socks-off mstr bathroom than f yourself by skimping on a decent, solid, & safe home's bsmt walls,,, then again, its YOUR family & YOUR house :whistling2:


Hey, if you know all the answers why are you just attacking my ideas for wanting to do something myself with your comic sans size 3 font? I would build a traditional wall to code with 8" block. Instead I am asking about better alternatives to the standard code and 8" block. According to you, they fail. But according to you it is the old block walls that are failing. I can not rent concrete forms to walls here, instead I would have to have it contracted out. What is wrong with wanting to build my own wall if it is safe and sound and to code. It won't pass inspection if I do shoddy work. Shesh.


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## jomama45 (Nov 13, 2008)

AlphaPilot said:


> The walls would be *6'* or possibly *6' 8"* below grade. The soil type seems to be clay, no tests done yet as to the true tech terms. I've dug in it, and what I have dug has been your general clay that is crappy for growing trees until it gets amended. (from a landscaping point).
> 
> If you looked at the link to the building code "HERE" that I attached earlier in one of these threads, you'd see there's "PSF" columns depending on your soil. The way it works here, is you assume the heaviest PSF unless you get a soil analysis taken.
> 
> I too figure 24,000 was _pricey_. I am guessing around 5 to 7k for materials. Including 10"W x 8"H x 16"L block @ 2.50 a piece, and just a random number for mortar, string line, and plumb bobs. Rebar around 40 cents a running foot, which I am sure that depends on the type. (*quick question* - is #5 like 5/8th of an inch and #3 3/8th of an inch when looking at code?)


The "#" for rebar is in eights, so a #3 is 3/8", and a # 12 is 1.5".


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## AlphaPilot (Aug 6, 2012)

Okay, I just wanted to make sure that was right with the code. And after I figure out what it is here, I likely will do what you suggested or do yourself where you assume it's the heaviest PSF and work with that. Better safe than sorry.


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## AlphaPilot (Aug 6, 2012)

Would you rather : Block your own basement in 8" or 10" blocks 8' high....OR spend money on lumber to make your own forms to do a solid pour? Both DIY.


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