Plywood Moisture Question

[joesxm3]

I just had the two skylights replaced in my bathroom. One over the shower and one next to it in the standing area.

The skylights were a close fit and installed with the Velux mounting kit so there are no issues with moisture coming in or getting into the attic, but there is a three inch gap showing some attic rafter and roof decking plywood.

I plan to simply get some 1x3 wood, cut and nail to the rafter and caulk the edges and put a good coat of paint on it to seal it.

My worry is that the edge of the roof decking plywood is exposed at the moment. I imagine that left like this for a long time the shower moisture would infiltrate into the layers of the plywood and delaminate it.

How much time can I get away leaving it like this without risking damage?

Is there some temporary measure I can do to protect it like painting the edge of the plywood with something to seal it until I do the more elaborate finish work?

 

[Gryphon]

I wouldn't worry about leaving it exposed for a few days, just try not to splash any water on it & don't take any hot showers to avoid steam.

You might think about using vinyl trim rather than painted wood. That's what I used to cover over a gap between the fiberglass shower enclosure & the drywall above it in my bath.

 

[pb4uski]

+1 No worries as long as bathroom is well ventilated and has a bathroom fan. From what you wrote I assume that the 3" gap is along the new skylight on the bathroom ceiling? Do you have a picture?

I do like the idea of vinyl trim instead of painted wood. Vinyl is final!

 

[joesxm3]

I will try to climb up and get pictures tomorrow. Long shot not enough and my bum knees are shot after crawling around in the attic pulling back insulation.

 

[JoeWras]

This is just humidity. Don't worry about it. If it were rain or direct water, we'd have a different conversation.

While this is going on, just take a little extra action. Run the fan for 1/2 hour or so. Maybe even run a fan in the bathroom to stir up the air.

 

[DrRoy]

If you are worried, a little varnish or something like that would seal it.

 

[Ronstar]

Maybe put on some Thompson’s Water Seal

 

[pjigar]

How much time can I get away leaving it like this without risking damage?

Every rain shower will have an impact. OSB deteriorate 10 times faster than the real plywood.

Is there some temporary measure I can do to protect it like painting the edge of the plywood with something to seal it until I do the more elaborate finish work?

Paint the edge with tight bond III glue. It is waterproof, sandal, paintable.

 

[joesxm3]

I ordered some Gorilla waterproof wood glue to seal the p!stood edges. That should buy me some time to figure out how to best do the finish work.

 

[calmloki]

You have concern about the roof decking plywood? Calmate. Notice the roofing jobs when you are out and about. All those roof sheathing lower edges are unsealed and exposed to ambient moisture. You are going to have the exposed plywood hidden by sheetrock, right? No worries.

 

[joesxm3]

Just worried about the time before I get around to covering it up. Busy taking care of parents and hard to get out to home depot.

 

[joesxm3]

Here are some pictures.

The larger stained section is sheet rock and was where the previous skylight reached down to. The 2-3 inch gap is what I plan to simply cut a 1x3 board to fit and nail to the 2x6 lumber behind.

The new window seems a bit larger than the old one. To do a professional restoration one might want to remove the sheet rock and replace with a larger piece. However, there is a double 2 inch board framing the window hole and that comes too far into the hole to be able to put a full new piece of sheet rock and have it line up with the groove in the window frame.

 

[Palmtree]

I thnk you should be fine but instead of wood & paint, I would recommend buying white PVC trim. It cuts and nails as easy as wood but you don't have to paint it. It's waterproof and it will never rot. Pefect for your project area.

 

[joesxm3]

Does it come in a nice 1x3x? Square format?

 

[Walt34]

Does it come in a nice 1x3x? Square format?

Sure does, I used some on my garage trim, replacing some rotted wood. I happened to buy it at Lowes but I think this is the same stuff:

https://www.homedepot.com/p/Trim-Bo...tual-719-in-x-2-5-in-x-96-in-424600/202085979

For unknown reasons Lowes' site is behaving badly for me today.

 

[Gryphon]

Sure does, I used some on my garage trim, replacing some rotted wood. I happened to buy it at Lowes but I think this is the same stuff:

https://www.homedepot.com/p/Trim-Bo...tual-719-in-x-2-5-in-x-96-in-424600/202085979

For unknown reasons Lowes' site is behaving badly for me today.

That's pre-painted pine. I was thinking more of this kind of stuff:

https://www.menards.com/main/doors-...ngs-e1e/5846371/p-1841405560629697-c-9561.htm

There are other options in the 3-4 inch range that have fancier molding profiles, this is as close as I could get to plain 1x3.

 

[Walt34]

That's pre-painted pine. I was thinking more of this kind of stuff:

Ack, you're right. I searched for PVC trim and didn't fully read the result. I know they have it though, I've seen it in the store.

 

[Music Lover]

I've seen new home sheathing and flooring exposed to the weather for several weeks to a couple months with no ill effects. And that was sheathing directly exposed to the weather. In your case it's inside an enclosed space, it will be fine.

 

[JoeWras]

I like the idea of PVC trim too.