Vapor barrier repair

[graycarpenter]

I started out by replacing my shower in my 5 year old home. I found out through this site and John Bridges' site that the base was not set well and there was no vapor barrier installed. I determined this after I had totally tore out the shower including the tile walls.

I also came to the conclusion that the builder did not install a vapor barrier behind the green board. I am now ready to reinstall the base using a cement sand mix to set it in.

When I started to put back the insulation I realized that the builder put it in with the vapor side to the outside. Not good in Virginia. I check other places in the bathroom and realized it is wrong side out everywhere I can see it.

I called the building inspector and I asked why that would be since the rest of the home that I have looked at has the vapor barrier installed correctly. He said that they require the builder to put unfaced insulation in the bath areas because with they want to make sure there was not two barriers, one behind the backer board and one on the insulation He said they do not move the insulation once installed and the builder just turned it around so he wouldn't know that it is not unfaced. (I guess the builder didn't want to waste time.

Now what to do. The building inspector said that the faced insulation would have to be pulled out with the facing and the cavity filled. He recommended getting a contractor to blow insulation back in. I'm wondering about foam insulation. Would it work to take the old insulation out through a hole at the wall between each stud and then fill the cavity with foam insulation?

I have a second bathroom and it may have the same problem. I will open the wall above the bathtup/shower and check the insulation there. I won't be able to tell if there is another vapor barrier installed but I guess I can bet there is none because the master bathroom shower had none.

Sorry this is so long but I felt I had to give all the details I could think of. The foam is available from Tiger Foam and be put in by myself.

[jadnashua]

The location of a vapor barrier depends somewhat on the primary hvac usage. Where people run the a/c most of the year, they put the vapor barrier towards the outside of the building, where heating is the primary use, it is put towards the inside of the building. You could be in one of those 'tween' locations - it could go either way. The goal with the barrier is to prevent the condensation point to occur in the middle of the wall, or to prevent the prevailing heavy moisture from being there.

Foam makes a great insulation - fills voids, helps in air infiltration issues, goes around pipes and wires. Blown in cellulose is better than fiberglass since it is less likely to support air currents, but needs to have a proper moisture barrier - think soggy newspaper - it would take forever to dry out if it got wet. Blown in fiberglass can end up denser than the batts and fits around pipes and wires, too.

The moisture around a bathroom is somewhat troubling, since it is both conditioned and a major source of moisture itself. So, all of that being said, you could leave the insullation, but reinstall it. Once you pull it out, take a razor knife and put slits in it, then you can reinstall it. Others may have some thoughts...

[graycarpenter]

After I posted the thread I called the local building inspector. He said they require unfaced insulation here in Virginia in the bath area because they don't want to have a double vapor barrier. I think they assume that the builder will put a vapor barrier behind the backer board which they did not. Since they placed the insulation in with the kraft face out they assumed that it was unfaced. He said they don't move the insulation to see if it is indeed unfaced they just assume that the builder if following the local code.

Quite a bit of assumptions. I'm going to try to get it fixed by using my building warranty which warrents insulation meets local codes. Wish me good luck.

Thanks for the information on the foam. I'm just leary because of the past problems with foam insulation where I think building were condemed.