I started building my garage 2 years ago and had to put it on hold. Now the dirt has been getting wet this summer and the weed are growing big. Do I need to dig down a foot or so and fill with structural fill or just scrape off the top and fill? Then compact it?
Under the slab
- Thread starter demaele
- Start date
G McKay
Well-known member
Are the forms up yet? Gravel in? I think we need a little more info here, please. Maybe even some pictures?
I do not have pictures but the exterior stem walls are in, waiting to pour the slab. The sub-soil is a mixture of clay/silt and does not compact very well. I have a source h3ere in Denver for class 1 structural fill for free, just need to pay for hauling. Also have a place to dump whatever I remove of the existing soil.
dewalt378g
Well-known member
- Joined
- Mar 17, 2012
- Messages
- 180
If you have any loam (topsoil), then that has to go. Clay soils can be problematic to build on. Don't pour your new slab on a wet high clay content subsoil. When the clay dries out and shrinks chances are the slab will settle unevenly and develop cracks. Get rid of as much clay as possible. Wait for a dry period (when the ground is most dry), fill in with your gravel/stone and run a plate compactor over the stone. Now you're ready for your wire/rebar and to pour the slab. Use some kind of a bond break or expansion joint to keep the slab from sticking to your foundation walls.
If you dig down and still have a high clay content there is a way of treating the soil with lime to somewhat stabilize it. I have never personally done this, but have heard of it as a solution for building slabs on problematic clay soils.
If you dig down and still have a high clay content there is a way of treating the soil with lime to somewhat stabilize it. I have never personally done this, but have heard of it as a solution for building slabs on problematic clay soils.
The basic rule is
"Nothing that may rot, and thus leave a void, under the slab."
When I worked for a plumbing contractor the did a lot of "big box" slabs the so called "site work" would include not only laying out all the under slab drain pipes but also tons of pea gravel to support them.
No between the slab and underlaying clay allowed but well draining pea gravel.
"Nothing that may rot, and thus leave a void, under the slab."
When I worked for a plumbing contractor the did a lot of "big box" slabs the so called "site work" would include not only laying out all the under slab drain pipes but also tons of pea gravel to support them.
No between the slab and underlaying clay allowed but well draining pea gravel.
Highbeam
Well-known member
Loam is not topsoil. Loam is just a grain size between clay and sand. Organics are what make loam (or any other soil) into what is often referred to as a topsoil.
You can have loamy sand and sandy loam. Nothing to do with topsoil.
dewalt378g
Well-known member
- Joined
- Mar 17, 2012
- Messages
- 180
Wow I am 0/2 today.... Learn something new every day...especially me...lol