Sill Seal Wall Framing On Concrete Slab

Exterior wall on slab must be out on the edge.

Sill seal wall framing on concrete slab.

Pressure treated on concrete slab for an exterior wall hi folks i have a concrete slab on my car port that i want to frame off into a garage. The slab is thin and has a crack from previous settling. Several companies manufacture products specifically to seal moisture proof sill plates that come in contact with concrete slabs and foundations. This prevents water from leaking under the bottom of the wall to the inside of the building.

The sill plate is treated to act as a barrier keeping out termites and other critters and keeps moisture from getting under the wall framing and causing water damage. The sill plate transitions between the foundation and the wood framing of the walls. Apply a bead of caulk along the inside perimeter where the sill plate meets the concrete slab if desired for additional. An exterior wall must be placed on the outside edge of the slab so the exterior siding laps down and over the edge of the slab.

When building a new structure it is critical to securely fasten items to the foundation or slab of concrete with the use of a sill plate. Most houses in america get foam sill seal laid on top of the foundation. This plastic foam product primarily works as a capillary break between the concrete and the framing. Flashing a wall sill plate on slab on grade if you want to see if there is a vapor barrier under the slab put some plastic sheeting down over it and see what you get for condensation.

As the weight of the framing crushes the foam slightly it also sort of works as an air seal but it is not a perfect seal by any measure because the top of the concrete is never perfectly smooth. Consider a wood shed floor treated lumber joists and plywood. How do you waterproof or seal a sill plate on a concrete slab as well as the wall sheeting that attaches to it. I was considering pouring a very small footer on the slab and tying it to the new concrete with all thread bolts and rebar.

The sill sealers are generally made from compressible polyethylene foam that you install between the foundation and the sill plate creating a air tight membrane that also helps to keep the sill. The sill plate is also what you attach your framed walls to.