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Pier foundation.

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TonyTheTiger

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Ohio
I am planing an approximately 16x40something residential structure. Single story. I want to make three 2x2 foot piers along each side. Perimeter joists will be 2-treated 2x10s supported on the outer edge of these piers. The piers will have embedded anchor points at each pier. Block will be above the piers on top of a 4" concrete slab. Can I legally do this? And how deep will the piers have to be (just to the frost line or deeper?).
 
County. Ohio. Yes. I know. Just the code is hard to understand. I intend to well exceed code for weight, wind and snow loads, also insulation. Just 8 or 10 lor 12 larger than necessary piers (every 8 to 10 feet) would be easier for me to do than a perimeter foundation. Piers would be topped with a slab with just the anchor embedded into each pier sticking through. Anchors would be joined by steel to doubled rim joists at angles.
 
I think you need to talk to a structural engineer.

If you find the code hard to understand then how can you have confidence that you will exceed code requirements?
 
Just trying to get opinions. Code says 4 inch wide concrete below frost line all the way around for a one story, but that doesn't seem like enough to me. Plus the piers would disturb less soil.

I also have a construction question. How do you get the forms off the footers once the concrete is set?
 
Lots of questions. Let's start with the load bearing capacity of the soil you will be building on. What is it? Did you have soil testing done for load bearing capacity at the level of frost depth? Are you near a body of water where you may need pilings? How about the flood plain elevation? What flood zone are you in? What is the snow load of you area as you have to include that into the loads imposed on your piers?
There is a reason I am asking these questions. The codes are not here to make things difficult for you, they are here to make sure your home does not sink into the ground or get blown over or have cracking on the walls every time the wind blows. It is about safety for you or the next chump that buys your house in the future.
As stated by Mark K above, you need an engineer as what you are doing is outside the prescriptive codes.
 
jar546 said:
Lots of questions. Let's start with the load bearing capacity of the soil you will be building on. What is it? Did you have soil testing done for load bearing capacity at the level of frost depth? Are you near a body of water where you may need pilings? How about the flood plain elevation? What flood zone are you in? What is the snow load of you area as you have to include that into the loads imposed on your piers?
There is a reason I am asking these questions. The codes are not here to make things difficult for you, they are here to make sure your home does not sink into the ground or get blown over or have cracking on the walls every time the wind blows. It is about safety for you or the next chump that buys your house in the future.
As stated by Mark K above, you need an engineer as what you are doing is outside the prescriptive codes.
Click to expand...

Golly Jeff, all he really wanted to know is how to remove the form boards.
 
TonyTheTiger said:
Just trying to get opinions. Code says 4 inch wide concrete below frost line all the way around for a one story, but that doesn't seem like enough to me. Plus the piers would disturb less soil.

I also have a construction question. How do you get the forms off the footers once the concrete is set?
Click to expand...


Not into concrete

Form release??


Or a big hammer?

https://www.homedepot.com/p/Kleen-K...orrosion-Coating-Spray-Bottle-30820/206965027


https://www.homedepot.com/p/11-1-2-lb-Compo-Cast-Soft-Face-Sledge-Hammer-57-554/203757918
 
R602.10.9 Braced wall panel support. Braced wall panel
support shall be provided as follows:
1. Cantilevered floor joists complying with Section
R502.3.3 shall be permitted to support braced wall
panels.
2. Raised floor system post or pier foundations supporting
braced wall panels shall be designed in
accordance with accepted engineering practice.
 
3000 lb per sq ft. Not in flood plain. Ground was dry at 3 ft. (Frost line is 30 inches). I don't know how to calculate weight of house, but it's small at 16x40. I would guess less than 50 tons. So in theory that would be 33.33 sq ft of pier so. 2x2 I would need 9 of them. Round it up to 10. 4 on each long side and 3 on each short side. Well within code span for doubled 2x10 too.

I guess it wasn't as hard as I thought...
 
tmurray said:
I'm not sure what the question even is. I mean there is form board oil that helps, but other than that, jump in the trench with hammers and pry bars...
Click to expand...

So that would mean a much wider trench than actually needed. I think I'd rather do the piers. I can auger the holes.
 
steveray said:
R602.10.9 Braced wall panel support. Braced wall panel
support shall be provided as follows:
1. Cantilevered floor joists complying with Section
R502.3.3 shall be permitted to support braced wall
panels.
2. Raised floor system post or pier foundations supporting
braced wall panels shall be designed in
accordance with accepted engineering practice.
Click to expand...

The piers won't be the ONLY thing supporting the walls, they'll just be the only part that extends to below the frost line.

I was planning on pouring the piers to 4" above ground level, then preparing the center part (compacted gravel with vapor barrier on top) and pouring a 4" slab (leaving openings for utilities). From there it will be enough block to make an adequate sized crawl space all the way around, and he house on top. Each pier will have a steel anchor embedded in it.
 
A recipe for disaster. A 4" slab on grade resting on piers?? No building official should issue a permit for this idea.

Don't believe that you can protect him from what he "knows" will work.
 
Mark K said:
A recipe for disaster. A 4" slab on grade resting on piers?? No building official should issue a permit for this idea.

Don't believe that you can protect him from what he "knows" will work.
Click to expand...

Part of me believes we are just getting trolled because this design is so bad. You know what. Let him build it without engineering if there is no code enforcement and see what happens.
 
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jar546 said:
Part of me believes we are just getting trolled because this design is so bad. You know what. Let him build it without engineering if there is no code enforcement and see what happens.
Click to expand...
I got the same feeling when he asked how to remove form boards. In another thread he's shooting for R-70 attic insulation.
 
TonyTheTiger said:
So that would mean a much wider trench than actually needed. I think I'd rather do the piers. I can auger the holes.
Click to expand...
It's probably cheaper to build on a code prescriptive frost wall than to build a engineered slab on engineered piers.

The reason that the code has prescriptive ways to do things is that is the typical construction technique in the field. It is the typical construction technique in the field because it is the cheapest.
 
Seriously? A 16'x40' residential structure with a total of six piers and the beams are double 2x10's?

Stop designing and hire a professional before someone gets hurt.
 
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