How can I protect the soleplate when framing basement walls?

Question

I plan on finishing my basement and I have a specific question about framing the walls and protecting the soleplate.

I plan on framing and setting up the walls BEFORE laying the subfloor, but that means I need to protect the soleplate from moisture. I plan on sealing the entire basement (thankfully it's fairly new and there are no cracks in the floor), but when I anchor the soleplate to the floor, it will obviously break this seal and potentially allow moisture to seep up around the fastener.

Should I do any of the following?

1. Put caulk/glue under the soleplate where I know I'll be anchoring it
2. Use washers or some other inorganic spacer to elevate the soleplate off of the concrete
3. Use a pressure treated soleplate

I would rather not lay dricore first and then frame on top of it as that makes the dricore much harder to remove if there is ever a flooding issue. I'd also prefer the walls to be more stable than if they were anchored to dricore subflooring.

Answer 1

Any framing that directly contacts concrete should be pressure treated. So option 3. Sealing is an optimistic concept at best, .vs. ensuring that there is proper drainage outside the basement, but you could certainly put construction adhesive on the bottom of the soleplate, it won't hurt.

Answer 2

You can't really stop leaks in concrete from sealing from the inside. Products like DryCor and epoxy seals are temporary solutions to water leakage problems, at best.

So if you have seepage issues, just do not finish the basement, as you will not want to rely on sealant as your only line of defense.

If it's just natural moisture that you are concerned about, then I don't think you need to over-think the penetration of a few nails into the concrete.

But you do not want untreated wood in contact with the concrete, so you're right about that.

Using pressure treated lumber will prevent rot, but not prevent it from wicking up moisture. So that's only half-solution. What you really want to do is create a break between the concrete and the wood. Two options off the top of my head:

• Rubber window flashing on the floor, wood floor plate nailed on top

• (my preference) 1/4" EPX foam, metal floor plate nailed on top.

I prefer using metal framing for basements for a number of reasons that I outline here.

Answer 3

You want water to escape, not sit. Ideally, you want a series of things:

1. Have a place for moisture in the basement to go. A sump hole with an optional sump pump at the lowest part of the basement is ideal.
2. Use a pressure treated sole plate on these interior walls.
3. Periodically, create breaks in the sole plate a few inches wide so in a worst case scenario the water can escape. You will put a continuous non-treated bottom plate on top of the treated sole plate upon which you will build your wall.
4. Bring the drywall or wall sheeting material down to the untreated bottom plate, but not over the sole plate.

After the wall is framed and sheeted, put baseboard over the gap between the sheeting and the floor. A few spacers there are okay. But don't seal it.