Proper way to pour a basement slab?

mebke33August 28, 2012

We are trying to decide on a sub for flatwork in our ranch style home with a walk-out basement. We have several differing opinions on how the the basement slab should be poured. One states that the slab should be in direct contact with the footings. The second states that the slab should float on a bed of gravel and not directly contact the footings. Is there a standard technique or is this just individual preference? Does anyone have any experiences, either good or bad, for either technique? Thanks.

Thank you for reporting this comment. Undo
lzerarc

my answer? it sort of depends on your climate. If you are at all in a heating climate, I would say both are not ideal. Incorrect? not really, just not ideal. However of the 2 options, I would side more with the gravel then the contact with the footer as it helps to give you a capillary break. If you are in a heating climate, there should be 1.5-2" of foam under the slab, and preferrably between the slab and the footer for a thermal break.

    Bookmark   August 28, 2012 at 11:57PM
Thank you for reporting this comment. Undo
virgilcarter

I'd say that a lot depends on the extent to which you have a water and saturated soils issue. Theoretically, if no water can get past the foundation walls the slab will never have any movement.

On the other hand if water gets under the slab it's going to move with the expansion and contraction of the soil when it is wet and dry.

Whatever you decide, be sure you have good drainage away from the foundations and basement slab. If moisture is an issue in your area, include a sump drain and pump. This will require a slotted space between foundation walls and floor slab.

The other comments about temperature are also important to consider.

Good luck1

    Bookmark   September 12, 2012 at 11:18PM
Sign Up to comment
More Discussions
Frank Betz Kensington Park - opinions and any pictures please!
In the Air Force, thinking about building the Kensington...
dnasmith14
Floor Plan/Kitchen Help - Please :)
I cross-posted this here in Kitchens as well. Please...
kymberie
It's February 2015- How is your build going?
January was a surprisingly active month! I admire all...
mushcreek
Spray Foam in Roof Rafters - Not Sure if it will Help
So my builder wants to spray foam all the rafters in...
TonySak
Add second story balcony before framing starts
My house's basement foundation will be poured sometimes...
houses14
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™