# cmu course layout???



## Willie T

Is it divisable by 10, 12 or 14? They make 10", 12" and 14" blocks.


----------



## figs

No.

I already have 8" x 8" x 16" block. How does one build the corner leads in this case?

thanks


----------



## Willie T

Kinda depends on how far you are off a multiple of 16, how big it is, and in which directions, etc. If the balance and aesthetics are important to you.

There are all kinds of ways to make blockwork come out right, depending on your inventiveness.


----------



## figs

It is about 14" off. So, do I cut 7" pieces for each side, and make the appropriate cuts for the second course so all joints are centered? This seems like a lot of cuts. Is there an easier way? We are most likely going to stucco the fireplace, but I would like to learn how to do the layout correctly.

thanks


----------



## jomama45

figs said:


> It is about 14" off. So, do I cut 7" pieces for each side, and make the appropriate cuts for the second course so all joints are centered? This seems like a lot of cuts. Is there an easier way? We are most likely going to stucco the fireplace, but I would like to learn how to do the layout correctly.
> 
> thanks


 
It sounds like your only 2" short of bond. Either clip or saw 2" (right behind the first,end web likely) off 1 block per course & lay wherever you want. Just keep the piece in the same area all the way up. If you dont have something to saw the block with, a good 4" brickset chisel may be in order. Hopefully you have a few extra block though if your going to chisel, as they break somewhat easliy if your new to it.

Also, we always try to keep our pieces 11" or bigger. If you cant, & need smaller pieces, try to adjust so you can use both pieces, as in 1 sawing or chisel = 2 pieces, alot easier. Ideally, you want to keep at half bond, but you can stray 1" or 2" without problems. Good Luck!


----------



## figs

So, it sounds like it is not bad practice to make the cuts at only one corner and not the other (keep all cuts at one corner and fill the rest of the courses with full 8" x 8" x 16" cmu)...correct? 

If the difference was something smaller...like 4", what does one do so the bond still looks good? Is there a general rule for dealing with these circumstances?

I have a diamond blade for my angle grinder. I would imagine that this would work for cutting the cmu. 

As for reinforcement (vertical and horizontal), what do you recommend for a fireplace (about 7' tall) with a sitting area about 20" tall? Spacing of rebar and wire? 

What should the distance be between grouted cells, etc?

thanks


----------



## concretemasonry

The use of reinforcement depends on the size, shape and height of the individual wall segments.

It is usually good practice to put a rebar and grout at every opening. A typical fireplace (even inside a house) may really not need any vertical reinforcement because it is such a robust structure with little ability to collect any load. The corners and relatively short horizontal dimensions give you something strong enough to resist a tank. If you were building a long straight wall 6' or more high out of 6" or 8" block you would typically put steel every 2'.

Often outdoor recreation items are not even covered by the IRC, but the west has a habit of prescriptively using reinforcement where it is not need and may be detremental.

It is always good practice to use horizontal joint reinforcement (Dur-O-Wal wire or similar) every 2 or 3 courses just for continuity, but it is not structural.

Dick


----------



## Willie T

Barbeques like yours are one of the reasons they make 14", 12" and 10" (sash) blocks. 
They even make an 18" stretcher.
That would normally be 88" across there if just 16" blocks were used, by the way.
Well...... really it's mostly because of door and window locations and interlocking (perpendicular) interior wall connections. :yes:
Notice that each one of these walls is similarly done with five and one half blocks, but they range from 84" to 90".
NOTE: If you go buy some, the smaller blocks often come with only one cavity. That's normal. They're not selling you a reject or something.


----------



## Willie T

figs said:


> So, it sounds like it is not bad practice to make the cuts at only one corner and not the other (keep all cuts at one corner and fill the rest of the courses with full 8" x 8" x 16" cmu)...correct?
> 
> *If the difference was something smaller...like 4", what does one do so the bond still looks good?* Is there a general rule for dealing with these circumstances?
> 
> I have a diamond blade for my angle grinder. I would imagine that this would work for cutting the cmu.
> 
> As for reinforcement (vertical and horizontal), what do you recommend for a fireplace (about 7' tall) with a sitting area about 20" tall? Spacing of rebar and wire?
> 
> What should the distance be between grouted cells, etc?
> 
> thanks


16" minus 4" equals 12".
You would use a 12" block if either you (or an inspector for your customer's bank, neighborhood association, etc) had a thing for only using full blocks.

And don't kid yourself that some of the high end communities don't get just that picky... and more. :furious:


----------



## jomama45

figs said:


> So, it sounds like it is not bad practice to make the cuts at only one corner and not the other (keep all cuts at one corner and fill the rest of the courses with full 8" x 8" x 16" cmu)...correct?
> 
> *Correct, that is standard practice.*
> 
> If the difference was something smaller...like 4", what does one do so the bond still looks good? Is there a general rule for dealing with these circumstances?
> 
> *When your laying out the bond, flip one of the corner block the 8" way vs. the 16" way, for example. Worst case, put 2 clipped block in per course.*
> 
> I have a diamond blade for my angle grinder. I would imagine that this would work for cutting the cmu.
> 
> *Should work better than chiselling the block.*
> 
> As for reinforcement (vertical and horizontal), what do you recommend for a fireplace (about 7' tall) with a sitting area about 20" tall? Spacing of rebar and wire?
> 
> *I would tend to agree with Dick on this, Dura-Wall is cheap insurance, if you can buy it small quantity. As long as your setting the block on a good footing, vertical re-enforcement is probaly overkill, unless your going over 10 or 12 feet high.*
> 
> What should the distance be between grouted cells, etc?
> 
> *1 rodded pilaster in the center of the back wall, maximum.*
> 
> thanks


Feel free to ask any more questions, I for one love building outside fireplaces! :thumbup:


----------



## NJ Brickie

Maybe things in my area are a bit different. I have never seen a "factory" 14",12" or 10" long block. 18" yes they are used for certain layouts to avoid a 2" piece. Also the cuts are always in the corner. IMO a bricklayer that puts a piece in the middle of a wall is a hack. If you need to lose 2" then start out with a 14" cut. If you are building a corner the next course would be the head of the block going the other direction then the 14"piece. If it is a lead the the second course would start out with a 6" piece.


----------



## concretemasonry

Will the fireplace be surfaced with something or all of the walls (100%) exposed on both sides?

If you are building 8" thick walls (which is probably overkill), you are dealing with the wrong block supplier. In some areas, they use 6" partially reinforced block for 20 story loadbearing buildings.

For an 8" wall, a 12" long block (8x8x12) is actually a 12" 1/2 long block (12x8x8). If you need a 14" long 8" block (8x8x14), it is just a 1/2 length 14" unit (14x8x8).

If it is covered, there is nothing wrong with using split of sawed incremental units of standard 8x8x16 units. There are times when you have to cut units to fit a specific dimension that is designed.

I know of block producers that had 1200 different units in inventory, but still had to make special size units for a specific design - For colored architectural CMU masonry construction some block were sold at a loss since the price was only about $25+ per block if the quantity was sufficient. In some areas, inventory selections are minimal because of the local use of concrete masonry and only 8" block walls were common in comparison to other areas where 2", 3", 4", 6", 8", 10", 12", 14" and 16" thick block were made for walls. - the associated fittings (corners, bond beams, lintels, etc.) and fractional units were also available.

The block availability is a manufacturer and regional thing.

Dick


----------



## Willie T

NJ Brickie said:


> Maybe things in my area are a bit different. I have never seen a "factory" 14",12" or 10" long block. 18" yes they are used for certain layouts to avoid a 2" piece. Also the cuts are always in the corner. IMO a bricklayer that puts a piece in the middle of a wall is a hack. If you need to lose 2" then start out with a 14" cut. If you are building a corner the next course would be the head of the block going the other direction then the 14"piece. If it is a lead the the second course would start out with a 6" piece.


Stick around, Jersey, you might be surprised at what's out there in the world.

Here's a fun one for ya, using factory 12" blocks and partition blocks.


----------



## jomama45

concretemasonry said:


> The block availability is a manufacturer and regional thing.
> 
> Dick


 
It must be, obviously. From what I've heard Dick, Minnesota is one of the last areas that still see alot of block foundations, in new homes anyways. As a child, I remember hearing my Dad say block : poured was 90% : 10%. About 12-15 years ago, about 50/50. Now maybe 5% block foundations. As a matter of fact, just this spring, I heard from our large block supplier/manufacturer that they will soon stop making full 8" high block. We just completed a new block foundation, & it was obvious they're at least not spending any money on the molds. Kind of sad to see in some ways, but I'm sure it will be better for my body in the long run!


----------



## concretemasonry

jomama -

You are right about the poor Wisconsin availability and creativity when it comes to block. Almost as bad as Florida and some other southern and eastern areas with a lot of unexposed concrete masonry. There are still some good architectural block made in Wisconsin.

In Minnesota, the cheap houses and townhouse development basements have gone to poured, but the better quality and larger homes are still block in the basements. Of course, the colored, architectural market percentage is still good.

Dick


----------



## Tscarborough

We carry a lot of specials, but we also charge a premium for them. For example a 8x8x12 3/4 block(2 core) or 12x8x8 1/2 block(1 core), costs $1.56 VS $1.35 for an 8x8x16. DYI'ers often complain about this, but the reality is that specials are run once or twice a year and have to be stored until sold. That is why they cost more.

Personally, I cringe when I see anything smaller than 4" in the wall with brick, and 8" with CMU.


----------



## Willie T

concretemasonry said:


> jomama -
> 
> You are right about the poor Wisconsin availability and creativity when it comes to block. Almost as bad as Florida and some other southern and eastern areas with a lot of unexposed concrete masonry. There are still some good architectural block made in Wisconsin.
> 
> In Minnesota, the cheap houses and townhouse development basements have gone to poured, but the better quality and larger homes are still block in the basements. Of course, the colored, architectural market percentage is still good.
> 
> Dick


Don' know why ya wanna knock Florida block foundations.... Here's one my brother-in-law ran up yesterday. The mortar didn't arrive with the blocks, so he figured he'd just pour it as a dry stack. :whistling2:


----------



## NJ Brickie

I may have worded what I wanted to say wrong. I know that there are thousands of different block made. Varying length, height, width, textures, and so on. Around here we cut our block. If you need a 14" piece then you cut a 14" piece. In this area the corner/intersection straps are not used that often. Also most times an intersecting wall is not physically tied. Wall ties are left hanging out of the wall and the intersecting wall butts up to it. I know the use of pieces and how to tie walls/ corners together. But to order factory pieces for something (unless a job calls for a thousand of them) is pointless. Unless it is something you use all the time like a factory half.


----------



## concretemasonry

The reason the mortar was not there is because the block he ordered were simple interlocking block that actually can give you lower strength than conventional block with mortar (whether you grout them or not). Obviously he was not planning on a head joint and the block with a recess for the bond beam are weaker when used in the rest of the wall that is not filled. - Just a way to minimize productions costs, but possibly good enough for the type of construction.

If you look at the block and the way they sit on the pallet, there is probably poor height control in manufacture that can be acceptable only if the walls use mortar and are covered.

Florida has some big producers, but is geared for a different type of construction that requires more strength in the CMU and better height control where exposed masonry is more common.

In Minnesota, the basement contractor are more critical than the commercial mason contractor that do only buried commercial work. A basement contractor orders and pays for the block and can do a job better and faster if the buys better block than the cheap stuff.

Florida has improved since I first wandered through the plants 30-40 years ago (when they only made 8 or 10 different block), but is still geared for minimal shapes avaialable for covered construction.

Dick


----------



## Willie T

T'was a joke, Dick. One of my brothers-in-law is a lawyer, and the other owns a chain of fast food restaurants. Although a few of my masons _might_ lay up a foundation that could resemble that pile on the pallet. :wink:


----------



## Willie T

NJ Brickie said:


> I may have worded what I wanted to say wrong. I know that there are thousands of different block made. Varying length, height, width, textures, and so on. Around here we cut our block. If you need a 14" piece then you cut a 14" piece. In this area the corner/intersection straps are not used that often. Also most times an intersecting wall is not physically tied. Wall ties are left hanging out of the wall and the intersecting wall butts up to it. I know the use of pieces and how to tie walls/ corners together. But to order factory pieces for something (unless a job calls for a thousand of them) is pointless. Unless it is something you use all the time like a factory half.


We too cut 98% of the time. And I see nothing wrong with it. But Florida lives with continually tightening codes, and more than a few communities now get very anal about "textbook" blockwork... as well as just about any other structural trade.

Some even insist that we use those "factory" rebar inspection blocks that come with a package of those silly little filler pads... as opposed to simply cutting our own.

And God forbid you get caught sticking a little filler piece in somewhere.


----------



## ArtVandelay

*CMU Wall Layout Graphics*

Hi Willie,

I like your graphic presentation for the CMU layouts on the first page.
Did you create these using Sketchup?


----------

