Upstate NY. My mother is in her 80's with a 1940's ranch home. 28' x 38' on a block foundation. A 10' x 12' addition was added in 1962. Under the entire house is an 18 inch crawl space. The addition never had heat because dad never got to it. The roof was built wrong to start with. A shed type roof meeting a 5/12 pitch at midpoint on the pitch is the worst design. Over the years the roof leaked badly at the junction. The water ruined the roof and interior. Finally after pestering from my brother and I, mom hired (she can well afford it) a contractor in 1990 to redo the roof. He installed a rubber type roof with asphalt shingles over that and the leaking stopped. No leaks since. In 1991 mom had me put in new wood paneling which went fine. That was installed with nails and glue over wall board.

However, the roof repair was too late. 25+ years of water had done its damage. The former lack of gutters forced the 10' wide foundation to move in 3 feet at mid point. The above wood structure of the same wall had rotted almost away. The ceiling had started to fall with serious mildew. The windows were falling out. The south side wall was in great shape so we left that as is. The north wall was good except where it joins the main house and the "L" is. I rebuilt that section.

Recently, myself and brother took mom in her wheel chair into that room. We showed her that I could push a finger right thru the wall to the outside. The sills were totally gone. Dry&wet rot were everywhere. But the floor was still in great shape. My brother then pushed on her window frame and it fell out. So we convinced her to use some of her stashed away money (she has enough) to have us boys fix it.

First came the distruction which is way more fun than construction. The roof drains off the 10' west facing part. We checked codes and found it was legal to install a 10' beam instead of block foundation. So we used five 2" x 10" PT lumber to build an 10"x 10" x 10' beam which sits on the side wall foundation. They were still great as if new & hadn't moved at all. It was easier than rebuilding the block foundation. Then we built a new wall using PT lumber, insulation, some wiring, gutters, installed new vinyl windows, sheetrock on the new wall & ceiling. Over the sheetrock we put some real nice looking quality wood paneling. Added finishing touches. Finally we spent our money on enough plants to fill the entire room so it looks like a jungle with grow lights. Mom was so happy.

NOW THE PROBLEM.....It is now 15 days later and the paneling has gotten wavy. We used adhesive and nailed every 12". The waves come away from the sheetrock 6" in places and run horizontal. The entire paneling has these waves. It appears that wherever there is no glue or nail it waved. My first thought was that because the old wall board was of that old paperboard type with no gypsum, somehow it was the problem. But the paneling waved away from the new sheetrock too. My brother thought it may be because the room has no heat and we had some 31 degree nights recently. I told him that can't be it because the old paneling held to the wall fine for 18 years w/o waving. But he is going to crawl under and put ducts in anyway. Better himthan me.

Obviously moisture is making the new paneling pull away. What do we do about it? Put in a vapor barrier of the clear plastic sheet type? Why happen now and not the old paneling? My solution idea is if we roll adhesive on 100% of the wall will that hold? My brothers solution is to remove the paneling and put on horizontal wood strips to nail to every 3". I think it would still wave between the strips. Could it be that the old paperboard has stored so much moisture over the years that we will need to take that off? If so then why did it wave on the new sheetrock too? And why did the old paneling not get waves?

I think the old walls were in such bad shape the moisture vented outside thru the walls. Now that all is sealed correctly moisture stays inside????? What do we do??? I think the easiest solution is rolling on adhesive on 100% of the wall.