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Forming Foootings

StephNow

Registered User
Joined
Oct 20, 2009
Messages
75
Location
Home of Larry Holmes
Do footings have to be formed?

I have in most cases required footings to be formed; recently I was questioned regarding the requirement because another inspector said that footings don't need to be formed.

What are your thoughts?
 
We require them to be formed. How will they install foundation drain at the proper location without forming?

docgj
 
109.3.1 Footing and foundation inspection.

Footing and foundation inspections shall be made after excavations for footings are complete and any required reinforcing steel is in place. For concrete foundations, any required forms shall be in place prior to inspection.

What makes it a required form I am not sure for foundations. My thought would be depending on the soils you have. For engineered pad footings if the sizes are not kept consistant by forms then there may be possible differential settlements between the pads.
 
How does one install the foundation drain below the top of the footing with a "trench pour"?

docgj
 
TT,

That will work. Just seems like a lot more work then forming it to begin with.

docgj
 
The soil can be used as forms as long as the loose soil will not slough into the concrete. When concrete is cast directly against the soil the IBC and I would assume the IRC requires a greater concrete cover.

I would not worry about the slight differences in footing size resulting in differential settlement. There are so many more significant issues.

Formed footings below grade would be required when required for waterproofing and where needed to maintain profile necessary to install other featurtes such as drainage. If there is a design professional involved he has a say in the discussion.
 
Guess it would depend on the soil in your area.

Here it's 12" deep and no forms needed. Other contractors will use forms. And a lot are simple mono footing (12' deep) with a 6" board on top of the ground for outbuilding buildings (sheds/garages).

Always with a clean trench.
 
All of our footings for SFD are inspected by 3rd party. We receive a report from the engineer before foundation and projection which we do inspect. Weird huh.
 
funny how we think structural engineers necessarily know more about footings than building inspectors do... I happen to have a relationship with the best lab/structural inspectors in the area.
 
Peach,

We have a lot shrink/swell clay soil and the county just doesn't want the liability. All footings here have to be engineered design, continuous and third party inspected unless it is a deck, small addition or detached structure.
 
A foundation drain just has to be below the slab or crawl space. It doesn't have to be below the bottom of the footing.

Footings don't necessarily have to be formed in shrink-swell soils as long as the soil is stiff enough to stand before and during the pour. Having the footings below the level of seasonal moisture change is the critical thing.

Minor differences of a couple inches in footing width don't cause differential settlement under typical light residential loads.
 
Contractors always form them here; we have sandy soil so a trench wouldn't work.

Footings have to be level-- I suppose it's possible, but can you really get a level footing (across the width as well as the length) in a trench pour? Do they screed it?
 
I've seen rebars pounded into the ground used as reference points.

Several years ago I built a garage and tried it, except I used 1/2" round plastic plant stakes instead of rebar, because I was too lazy to buy a long rebar and cut it into pieces. The concrete was thick enough to bend the stakes as it flowed into the trench, so the top of the footing elevation varied by 2 - 3"! I had a lot of fun making up the difference in only 4 courses of block. That garage was quite an educational experience. I found that it's a whole lot easier to draw buuildings than to build them.
 
Almost always soil here. Depth here is 18", not 12" as the CBC calls for due to the frostline. I check trench for depth, reinforcement, and cleanliness before pour.

Sue, in sunny CA
 
I've only seen one building here that had formed footings..... it was a Mormon Temple and the contractor was a good ol' boy from Utah who insisted that the footings be formed, it looked nice and clean!
 
formed footings are fine... getting the forms back out is sometimes problematic. And you've removed more soil than necessary.
 
peach said:
formed footings are fine... getting the forms back out is sometimes problematic. And you've removed more soil than necessary.
We've used gyp board at times for trench footings when the excavation hasn't been nice and clean, using dirt and rocks on the outside of it to keep the concrete from getting distorted, always with the top of the footing being wood. The nice thing with the gyp. board is you can leave it in place when done...............
 
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