My first major project – Fix damage from leaking window

[davidharris]

Hello all,
I have decided to tackle my first major repair project and I need some help and hopefully some encouragement. The kitchen window in our ’96 Coachmen C-class started to leak and water was pooling up on the counter top. I decided I would endeavor to fix this correctly and started find out how bad it had become.
I started probing around the window and the whole wooden frame was rotted. I have removed the counter top, stove, and all cabinetry below the window. I have removed the wallpaper and as much of the rotted plywood as I can at this point. Obviously, I am going to have to remove the window and replace the wooden frame. There is also quite a bit of delamination of the fiberglass on the outside and I suspect the outer layer of plywood is also rotted. The fiberglass itself seems to be in good shape so I am hesitant to do any work from the outside.
Should I remove the foam core and replace the plywood on the outside? Or, can I just replace the wooden window frame and install a new piece of plywood on the inside? I would like to fix this correctly but I am afraid to start cutting into the foam core or the fiberglass.

Here are the pictures:
http://s1268.photobucket.com/user/drummerdharris/library/RV%20Repair

Many thanks in advance!
David

[DaHose]

I sealed my windows with butyl tape. You can have some extra insurance by sealing around the outer edge with some ProFlex or Dap Alex sealant from Home Depot.

Jose

[msgross]

I plan on using PL premium adhesive from Lowes/Home Depot. Get a small caulking gun and a few tubes. You can also buy the small metal plates with holes (check decking section of Lowes) to hold the wood frame together. If you use pressure treated then get decking screws made for PT wood. I would worry about the foam being glued, just cut new foam the exact size and it will stick into the cavity. You can use a touch of the same adhesive. I would replace the wood, glue it to the outside fiberglass and lean a piece of plywood against the outside with weight to make sure it sticks, then finish the inside.

[davidharris]

The water damage extends about 4 to 6 inches above the window and the wood is solid above that. The damage below the window is significantly worse than above so I don't think it was the roof. The delamination on the outside is only below the window.

I have removed the interior plywood, the foam core, and the loose plywood not stuck to the fiberglass below the window and some above the window. I am close to start cutting replacement wood and foam.

What is the best adhesive for the plywood to fiberglass and then to the foam and the internal plywood?

As for the window seal I am thinking about eternabond's putty but I know it can be a mess.

David

[msgross]

Is it rotted above the window as well? If so then it was your roof leaking. I'm doing the same repair right now and had to remove the fiberglass on the outside. Mine was rotted down to the lower sill of the wall. Since i'm doing the roof and all it was easier to go this route for me. The outer skin of the outside plywood will stay stuck to the fiberglass. Need more outside pics of yours to assess the scale of the delamination.

The window was originally installed with butyl tape under the lip of the flange. You could either do that or get some good quality window sealant at the box store. I'd finish it off with RV sealant on the outer edge of the frame.

[k9-keno]

What would everyone use to seal the outside of windows?? Black outside window silicone???

[davidharris]

Great idea bumpy. I can use the git-rot epoxy at the edges of the areas I am not replacing for additional strength.

[Bumpyroad]

don't forget to get some "get rot" I think to soak the boards you have to leave in there.
bumpy

[davidharris]

Thanks Bumpy. I know I can get the majority of bad wood out from the inside. I expected to find studs behind the plywood but it looks like one big piece of foam core with plywood on either side.

[midnightsadie]

bumpyroad has some good Idea,s if it was mine I would not cut the outside. good luck do it right and it,ll look great.

[Bumpyroad]

If you can get fully to the inside and remove all of the rotten wood that was laminated to the fiberglass sheeting, I think I would leave the outside alone and glue panels to the inside. clamping the pieces together would be a problem, a large C clamp thru the window would anchor some of it. If you cut up the outside fiberglass sheeting, unless you replace the entire side or very large section, it will end up looking like a tacked together mess, JMHO.
a board could be nailed to the floor in the cabinet to push out against the bottom and somebody here parked next to a building and pushed against the outside wall to glue things back together.
good luck, and keep us posted.
bumpy