Foundation questions brick or poured or slab

[JBAUTO]

Hey guys.

Ive been serching for a house now for over a year and found something i like.

My goal is to build a 30x30 12 foot high garage so i can do some work.

Now i will be building the walls and the roof and will be gettin truss made up. I have students at my work that need training and they offered to help me build my garage.

Now my delema is. The foundation. The guys have no problems doing a slab pour as they do this here and other locations all the time. Im wondering what would be best for me to do a Brick footing witch i can build on my own and threw help at work. Or pay $5,000 to get a 4ft concrete poured wall then me and the guys pour the concrete slab our selves.

I live in ontario canada and i will be doing in floor radiant heating.

So what would be the best option for me block wall with free labour or to shell out $5,000 just for a footing and wall?

Any input would be great.

 

[JBAUTO]

From my math i need 113 blocks per wall so this would mean 452 blocks to get a 30x30 and 50" high wall roughly. This would be with 10x16" blocks. And i priced out blocks and rember them being $3 a block so that would get me roughly this figure

Blocks $1352
Slab poured $1750
So that would put me at $3102 plus tax plus rebar and crushed stone and concrete for blocks.??

 

[p_mori7]

Many municipalities in Canada no longer allow cinder block foundations...suggest you check with your city hall first...I am planning the build of a 16x28 in my backyard (near Montreal) and will be going with floating slab 5.5" thick with 12" of prepared subsurface and good perimeter draining. My father & I build 2 14x24 about 8 years ago in the Laurentians and they have never moved yet.

 

[tcianci]

Even if you do a block wall, you will probably be required to have a footing for the wall to bear on. In many cases the footing requires so little concrete that you will end up paying a premium price per cubic yard. Even though, the footing and walls are usually done in 2 separate pours, I have often worked it out wiith the concrete company that since my total yardage was above the minimum, they would not charge the premium on the smaller pour. Also the poured wall gets you to the point where you can begin your frame many days faster than building a block wall. If you are building the block wall alone, you will need to stop and mix batches of mortar too. If you are going to rely on "free" help make sure the guys you have there have the skill to build an accurate foundation or it will haunt you right to the ridge!

 

[srmofo]

My footer was dug and poured in about 8 hours with 2 guys.The average size of footer is about 30"x24", some spots were sandy so the inspector made them dig out a little wider/deeper. one spot in paticular is about 6'x8'x 35"deep solid concrete. Theres more concrete there than you think. My footer alone was about 25 yards

Then 2 different guys built my 24x36 block stem wall in about 7 hours.

Then it took a team of several guys to pour the slab, most of that time was spent waiting. it was a chilly day and the sun didnt come out till late afternoon.

After attempting to help a buddy brick a chimney last year, I can tell you that there is ALOT more involved in brick work than just throw some mud and stack a brick. I agree with the guy above in getting experienced help. The foundation is the only part you cant go back and fix after its done....not easily anyways

 

[JBAUTO]

Im building in belleville near toronto. Ive heard now from another friend the same thing about the brick foundation.

So im guessing $5000 plus 1750 for 10 Meters or concrete and mesh and my foam and pex piping and back fill i will be around $7500-8500 for the concrete.

Yeah the guys that will be doing the work work for the government and went to school for this and have done brick buildings and shelters and bunkers

Im guessing maybe a quick phone call to town hall and ill crunch some numbers on how much concrete i would need for a base pour below the brick

 

[jklingel]

You will need a footer, no question. Are ICFs an option? You can stand up and brace the ICFs yourself, and you get an insulated foundation wall, too, which I assume you are going to have anyway w/ radiant floor heat. Put plenty of XPS under that slab, IMO, 4 to 6" if the place will be heated all the time (if not, radiant may not be that good of a choice).

 

[Gary S]

Are you allowed to simply pour a floating slab with thickened edge? That is how it is done here, and it seems to be the cheapest, fastest, and easiest. Put your anchor bolts in the slab when it is poured, and build the walls right on top of it.

 

[srmofo]

Are you allowed to simply pour a floating slab with thickened edge?

Are you talking about a monolithic pour?

 

[Snap50]

I wouldn't do anything but concrete all the way.

Just a concrete footing under block or brick has very little capacity to act as a beam to bridge soft spots (which may be deeper that you dig, so unknown to you) because it is so shallow. Beam action is much greater in deeper members (think 2"x4" vs 2"x12" wood floor framing) .The result is that you don't have much defense against settlement with a masonry wall atop a concrete footing. And keep in mind that masonry is very susceptible to settlement cracks. Take a look at some of the older masonry block buildings in your area.

If you use a concrete wall, reinforced with a couple continuous horizontal rebars in the top and bottom of the wall, you will have the best and most worry free solution; great beam action. Of course the consrete wall sits atio a continuous concrete footing.

A bad solution is to have a slab pour run into a trench to form an integral foundation; that is unless you like uncontrolled cracks in your floor. Concrete is subject to shrinkage cracking when curing, in the early life of the concrete. Imagine that you have your relatively thin slab tied directly into a thick mass of wall concrete. And you will have a big mass at the wall area because you need to go pretty deep up there to get below the frost line. The slab will cure faster and try to shrink away from the wall and.....random and uncontrolled cracks.

The better solution is a separate wall and slab with a natural joint (think crack substitute) where the two meet. Then you have a nice straight joint line.

If you want a long term worry free solution, spring for the concrete and a bit of rebar.

 

[Gary S]

Are you talking about a monolithic pour?

I'm not familiar with that term. We call it a floating slab. It looks like this.
http://home.howstuffworks.com/home-improvement/repair/house4.htm
We don't use it for houses, but for out-buildings like garages, it is very popular, and since it isn't residential, it doesn't need to go below the frost line.

 

[srmofo]

I'm not familiar with that term. We call it a floating slab. It looks like this.
http://home.howstuffworks.com/home-improvement/repair/house4.htm
We don't use it for houses, but for out-buildings like garages, it is very popular, and since it isn't residential, it doesn't need to go below the frost line.

that would be it. its funny how things are called different in different regions

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If I planned on staying anywhere fora period of time I would make sure to go below the frost line. thats just headache waiting to happen, just to save a few hundred dollars

 

[Snap50]

that would be it. its funny how things are called different in different regions

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If I planned on staying anywhere fora period of time I would make sure to go below the frost line. thats just headache waiting to happen, just to save a few hundred dollars

You are pretty much guaranteed to get cracks where the haunch meets the slab; going from thick to thin is a no-no for slabs.

Around here, there is no choice but to go to the frost line. It's code, even for things as insignificant as deck piers, so it's best to know ahead of time rather than when the inspector shows up and puts the brakes on things.

 

[KustomZ]

that would be it. its funny how things are called different in different regions

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If I planned on staying anywhere fora period of time I would make sure to go below the frost line. thats just headache waiting to happen, just to save a few hundred dollars

Thats how they are going to do my garage with the only difference being a footing dug below the frost line poured to ground level and the the slab poured on top of the footing. They are doing the same in alot of new homes around this area also.

 

[Snap50]

It always amazes me what lack of knowledge residential construction exhibits.

 

[mmurphy]

I have seen several floating slab type garages here in Iowa where frost is typical of 42'' at times, that has been around for decades and are still in very good shape. And most do have an extra thickness around perimeter that would not make it a monolithic type slab.

 

[JBAUTO]

Grrr i guess im going to do a 4 foot foundation wall. Im trying to budget either i pay $5,000 plus tax or do it myself. Pay for the ply wood and the rebar and cement myself. I have to talk to the engineers at work.

 

[dodgeram2500]

Check out the link in my signature for a slab-on-grade/monolithic/floating slab pour. I'm in Thunder Bay, ON where it gets pretty frosty. The garage hasn't moved. The key is a good compacted base and rebar. Think of a floating slab as an upside down bowl...As long as your base is solid hows the slab going to move? I overkilled the rebar on my build, If I did it again I'd probably go 3' on centre with 6" mesh laid on top.

 

[Gary S]

You are pretty much guaranteed to get cracks where the haunch meets the slab; going from thick to thin is a no-no for slabs.

Around here, there is no choice but to go to the frost line. It's code, even for things as insignificant as deck piers, so it's best to know ahead of time rather than when the inspector shows up and puts the brakes on things.

I did my garage like this. My winter weather reaches -45, and my slab still has not cracked where the thickened edge meets the thinner center. Summers here exceed 110 degrees, so very few places on this earth can beat that. In a winter with limited snow cover, the ground freezes down to 6 feet. The thickened edges of my slab are down about 18".
When I poured my slab, I rented a concrete saw and made relief cuts across it every 12-16 feet like the inspector recommended. Every relief cut eventually cracked on the line like it was intended, but no cracks occurred where the thick to thin transition was made.
People who spend more money doing it other ways want this simple and cheap method to be inferior, but it doesn't happen that way.