how wide and deep should my concrete foundations be ?

Answer 1

I am going to assume a general house as the type of structure you are building and I am going to say for the fact of saying that it is 2 stories with a footprint of 32x48 just to answer this question.

Concrete Poured should meet code. Thickness is 16 inches min. As far as for down to dig and set your footer that will depend on local code and the frost line depth in one area is different in another here in Kentucky it's 18inches so the answer would be 16inches wide and set 18inches deep with a thickness of 6 inches. Then you have the choice to place blocks on top of the footer or pour in place a solid foundation. I always use solid foundations and lots of re-bar and wire mesh. I like to have more then enough then not enough. Plus if you skimp you may be inviting in cracks and breaks which allow water in if the water table is high or you have build in a poor drainage area or other reason.

ALSO I buy(this is key) all concrete I use with fiber added and a PSI of 4000 plus to make sure of no future issues.

Answer 2

Concrete Foundation Depth

Answer 3

The rule of thumb is to keep your thumb away from a hammer.

With that being said this is the way we have always laid out our footers when I was working with the concrete crew.

12" x 24" you first have to excavate to virgin soil this depends on where you live. But this is a standard on matter were you live.

The best advise that you can be given for the info that you want is to contact your local building department and ask the inspector of buildings what the minimum requirement is for a footer. Be prepared to answer additional questions before you get your desired answer though, such as what type of building do you plan to build, whom is the contractor you plan to use, have you had the lot perc tested yet?, etc. etc. etc.

Perc test = the amount of time for water to be absorbed into the soil.

One other piece of advise I will give you is this, make sure whom ever you have pour your concrete, they use the proper concrete mixtures IE., footer mix for footers, foundation mix for the foundation, and floor mix for the floor.
The footer mix is usually at a strength of 1800 lbs.
The foundation mix is usually at a rate of 2400 lbs.
The floor mix usually starts at a rate of 2400 lbs and up depending upon what you intend to install in this structure

One more thing to remember I do not care who tells you that if you add a fiber mesh to the mix it will not crack, they are full of DUDU concrete will crack regardless of how much fiber mesh or wire mesh or rebar is installed prior to the placement of the concrete.

ALL COCRETE WILL CRACK. PERIOD. END OF STORY...

Answer 4

this depends upon the frost line in your area. a house foundation is generally 8 " wide. the footer (which the foundation walls sit on) is generally 8" deep and 16" wide. but this all depends on the weight of the building that will be placed upon the foundation. an architect is your best bet for the proper dimensions.

Answer 5

Your foundation should be at least 18" deep, and be 8" wider than your foundation wall. If you have an 8" foundation, you should have 4" on each side at the footing. So for a 8" foundation, the footing width would be 16".

Answer 6

The size of the foundations are governed by the sub-strait that you intend to build upon, your architect should give you a guide but a lot depends on what you come across when you are digging them out, with any luck you will be building on solid ground that is more substantial.

Answer 7

building inspector states it should be 900mm deep and 600mm in width but you dont have to fill to this depth with concrete if you want you can use some blockwork to reach the height, just ask your bricklayer what can you lose he will be laying on your foundation so he might say fill to depths with concrete as it will be easier for him.

Answer 8

3 times the width of the wall you are building and a 6inch start then 1inch for each foot of height is a good foundation

Answer 9

There is only one person who can answer that for you, your local builing inspector or your local building department. Codes are different everywhere, depending on everything including the inspectors mood.

Answer 10

Check the building/permit office at your city hall.