Expert: Jamie Yocono - 9/21/2008

Question
Hello, Please let us know if we made a mistake.
One year ago we put in a custom wood window in our bathroom.
The window is located directly over the sink so it will have to survive the normal splashing of washing ones face.
Also there is a typical shower inside of the bath. The one side of the window is in the bath shower area. The trim was done in mdf. Everything was primed with oil primer and 2 coats of oil base semi gloss.
One year later the mdf trim is swelling.
Can you give me your opinion on this. many thanks ron

Answer
Hi Ron,

MDF probably wasn't the best choice of material for trim in a bathroom. See, MDF is sort of like a dry sponge. Moisture will eventually enter it, and when that happens, it will swell up, which is what you're seeing. Even with the best efforts of sealing it, moisture can still enter it. That's what is causing the problem.

I think the good news is that the window itself wasn't made of MDF, only the trim. My best suggestion would be to live with it as long as you can. Then - you'll eventually want to pull it off and put up some solid wood trim.

Of course, you'll want to take the same precautions as before - primer and good paint. Wood should "behave" much better than MDF.

In the bigger picture, I think your predicament isn't the worst thing I've heard about. I get questions from people with all sorts of nightmare situations - cabinets falling off the walls, or wood splitting in the middle of a tabletop. Or worse. Your trim problem seems confined to that one window, and just a few hours of work and a few dollars will solve the problem. You might even ask at the lumberyard about plastic casing. Normally, I don't go for "fake" wood products, but plastic trim would be extremely stable in your bathroom, and would be a perfectly acceptable solution to your moisture problem.

Good luck, write back if you have any more questions.

Jamie Yocono
Wood It Is! Custom Cabinetry
Las Vegas, NV
www.wooditis.com