What this covers
- House slabs on grade
- Footings and piers
- Slabs poured around plumbing
- Work from the builder’s plans
The soil comes first
Soil under a slab is not the same across Tim’s area. Using USDA soil survey data, we sampled every town he covers. Woodlake’s soils are mostly rated high for shrink-swell. Visalia and Hanford are mostly low. See the soil table on each town page.
USDA’s California soil interpretations say that when shrink-swell is moderate or worse, shrinking and swelling can damage buildings, roads and other structures. Foundation design for your lot comes from the plans and the local permit.
Vapor retarders under interior slabs
NRMCA says vapor retarders are frequently specified under interior slabs where floors will be covered with carpet, tile, wood or other moisture-sensitive flooring. It recommends materials meeting ASTM E1745 at a minimum of 10 mils thick.
The same guide warns that a retarder directly under the slab increases bleeding and the risk of cracking, so finishing has to wait until bleed water is gone.
Recent foundations work
Where Tim pours foundations
Questions people ask
Do you pour house foundations?
Yes. House foundations and slabs are on Tim’s service list.
Does the soil in my town matter?
Yes. USDA soil data shows very different shrink-swell ratings across Tim’s area. Each town page has a soil table.
Should there be plastic under my slab?
NRMCA says vapor retarders are frequently specified under interior slabs that will get moisture-sensitive flooring, at a minimum of 10 mils meeting ASTM E1745. Your plans govern.