Foundation Thickness and Form

[mstang1988]

Ok, I think I'm finally going to start the oven! Plans have been done for a while and just need to submit them to the HOA and start digging. I was originally planning on doing a 12" foundation due to the tendency of the earth to shift in my area and supporting of the natural stone finish. does this seem too thick? If not, how do I frame the foundation so it finishes nicely if some is above grade?

I'll start a thread for my build as soon as the HOA approves the plans :-)

[mstang1988]

Re: Foundation Thickness and Form

I should specify it's a 42" oven.

[gdest]

Re: Foundation Thickness and Form

12" sounds way to thick. What you need to do is concentrate on your footing. Dig your footing down to what ever depth your local building codes suggest and lay down a layer of rock and compact this. This is where you can be 12" thick.
Then you can lay in your rebar and tie that together. For the interior of the slab you can usally get away with laying down wire mesh but you can also install rebar. This slab should not be more then 4" thick. Any thicker you are wasting money since this section of the slab see's no real force or weight.

[mstang1988]

Re: Foundation Thickness and Form

12" sounds way to thick. What you need to do is concentrate on your footing. Dig your footing down to what ever depth your local building codes suggest and lay down a layer of rock and compact this. This is where you can be 12" thick.
Then you can lay in your rebar and tie that together. For the interior of the slab you can usally get away with laying down wire mesh but you can also install rebar. This slab should not be more then 4" thick. Any thicker you are wasting money since this section of the slab see's no real force or weight.

The load I am worried about is the stone here. 5" thick and about 1 ton/ 75sqft and if I remember right it's about 500 square feet of stone. Combine the weight of stone and the cement block footer, hearth, insulation, cement counters and cement roof it's going to be on the heavy side of things.

http://www.fornobravo.com/forum/f35/...atio-8861.html

[Tscarborough]

Re: Foundation Thickness and Form

Add up the estimated weight of everything and divide by the foot print and you will find that the actual structural requirement falls somewhere around packed dirt. In RR, I assume you are east of 35 in the gumbo, so you will want to go a little better than packed dirt, but the standard for you is:

8-12" of compacted road base extending at least 6" beyond the edges of the final slab.

4" concrete with #3 rebar 12" O.C. in both directions. If you are truly paranoid, you can put a beam around the perimeter that is 8x8.

I am here in town, so call me if you have any questions:

Tom 821-3303

[mstang1988]

Re: Foundation Thickness and Form

Add up the estimated weight of everything and divide by the foot print and you will find that the actual structural requirement falls somewhere around packed dirt. In RR, I assume you are east of 35 in the gumbo, so you will want to go a little better than packed dirt, but the standard for you is:

8-12" of compacted road base extending at least 6" beyond the edges of the final slab.

4" concrete with #3 rebar 12" O.C. in both directions. If you are truly paranoid, you can put a beam around the perimeter that is 8x8.

I am here in town, so call me if you have any questions:

Tom XXX-XXXX

Tom,

Yes I live east of 35 around the outlet mall. You seem to be a pretty experienced builder, how tough do you consider this project? Do you have any good sources on materials in the area besides firebrick such as mortar etc?

[Tscarborough]

Re: Foundation Thickness and Form

I have sources for everything you need, I am in the trade.

[mstang1988]

Re: Foundation Thickness and Form

I have sources for everything you need, I am in the trade.

Fantastic! Also, I want to do all the work but the exterior stone. Do you have any good suggestions on who will do a good job at the right price? I would actually like to learn to do the stone but don't want to ruin my wonderful to be oven.

I was also told to leave 5" for the stone guys. Does this seem correct?

I also noticed the original plans suggested 6" foundation but you suggested 4". I'm surprised, I would have expected 6-8" in our area. I'll check the load and find out I suppose.

[Tscarborough]

Re: Foundation Thickness and Form

You can do 6", it won't hurt anything, and will help if the sub-base isn't perfect. You should do all of it yourself, but if not, I can give you the names of a couple of masons.

[mstang1988]

Re: Foundation Thickness and Form

You can do 6", it won't hurt anything, and will help if the sub-base isn't perfect. You should do all of it yourself, but if not, I can give you the names of a couple of masons.

How hard is it to do stone work like that? I know the materials are pretty cheap when I looked into it. About $100 for a ton if I remember right.

[Tscarborough]

Re: Foundation Thickness and Form

It is hard labor and skilled labor, but it is fun to do. Start in back and you will figure it out. Also ordering a chopped 4 sides 4-6-8 mix will make it easier.

[mstang1988]

Re: Foundation Thickness and Form

It is hard labor and skilled labor, but it is fun to do. Start in back and you will figure it out. Also ordering a chopped 4 sides 4-6-8 mix will make it easier.

Do you have contacts for concrete in the Austin area that will deliver 1.5 yards to Round Rock? My plans have finally been approved and I am ready to get this project going! Also, I need to source the high temp mortar for the oven. Who do you suggest in the area?

Thank's a million!

[FrankT]

Re: Foundation Thickness and Form

I'm also getting started, I'm scheduling my pour for Friday afternoon.
I will have a mixer and 30 bags of quickcrete.
I have looked into getting the mix delivered but the minimum order is 3 yards to Cedar Park and I really do not want a big cement truck at the house.

Are you using a vapor barrier under your slab?

good luck on yours...

[mstang1988]

Re: Foundation Thickness and Form

I'm also getting started, I'm scheduling my pour for Friday afternoon.
I will have a mixer and 30 bags of quickcrete.
I have looked into getting the mix delivered but the minimum order is 3 yards to Cedar Park and I really do not want a big cement truck at the house.

Are you using a vapor barrier under your slab?

good luck on yours...

Frank, how did the pour go? Are you looking for fire bricks at all? At some point I bought far too many so we might be able to work out a deal :-)

[Tscarborough]

Re: Foundation Thickness and Form

Sorry, Imissed your question. I got your PM and prefer to answer here so it may help someone else.

Your contractor wants to pour your slab monolithically, and that is not a problem, although his reasoning is flawed. If the oven/kitchen foundation is poured at the same time as the patio slab, there still needs to a difference in the dirtwork. The patio is just 4" deep with wire and/or fibers, while the oven and counter slabs needs to be a little more robust, with some rebar, and possibly beams around the perimeter.

I do not do masonry work, I am on the other side of the fence selling masonry products. You should do it all yourself, if not call me and I will give you a couple of names. 431-0870.

In the Austin area there are 3 companies that sell firebrick, refractory cement, etc.

Acme Brick has fire brick and wet mix refractory cement, and their sister company Featherlite should have perlite.

AHI has fire brick and wet mix refractory cement and fire clay, and may have perlite.

MPI has a full line of refractory cements, firebrick, and perlite.

Also, Elgin-Butler brick in Elgin will sell cheap #2 firebrick if you go pick them up.