I bought a new house last August and now I'm in the process of developing the basement.

A few walls were already in when I bought the house, the walls under the staircase. You can clearly see they were put in first, with a plastic vapour barrier under it, and then concrete floor was poured around it.

But the builder has also furred the concrete walls. I have a townhouse so the front and back outside walls are insulated and have a vapour barrier.

But the 2 party wall are just framed, but I don't see that there is any plastic under the bottom plate, between the concrete and the wood. The wood looks like regular framing, not pressure treated. They are nailed to the concrete.

I am a bit worried that the outside walls also don't have a vapour barrier between the concrete and the bottom plate.

Should I be worried?

  • I don't know that the vapor barrier between the concrete and wall are as much of a concern as having a standard stud on the concrete is. In the municipality I live in, you must have a treated board where it will touch concrete. If you could provide pics of the situation, it could help better understand your scenario. – Edwardt May 25 '15 at 13:18
  • I took out 3 pieces today. First picture shows it's done on the wall under the staircase, the rest are random spots through the outside walls. imgur.com/a/o1P3F – Roger Far May 29 '15 at 2:52

If you are inside your home's warranty period, now is the time to check with your local building authority to see if pressure treated lumber is required for plates in contact with concrete. There's a good chance the answer is yes.

If the builder has to come back and fix, its pretty straightforward to change a plate.

  • I will check yeah, but it's not really straight forward. I already build new walls, put down a floor etc. Also the wall goes around pretty much completely, so they would have to rip it out and rebuild it most likely! Which can be hard because there is electricity already in it... – Roger Far May 25 '15 at 14:17

Turns out that there is a vapour barrier UNDER the slab, which so far has held up fine.

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