Ask the Remodeler: Fixing a sliding glass door that isn’t plumb

Renovation expert Mark Philben also tackles a reader's question about damage in a vacation home. Get more expert advice at realestate.boston.com.

The track for this reader’s sliding door is sagging. Handout

June 23, 2021

Q. During a major renovation 10 years ago, our contractor removed a decades-old aluminum sliding door and replaced it with a much heavier double-paned slider. But instead of mounting the new door solidly on the basement’s concrete slab, he installed it with about half of the sill, including the track, hanging over the edge. The consequence quickly became apparent: The support has failed, the track is sagging, and the slider won’t close properly. The contractor’s fix was to fabricate a wooden support by nailing 2-by-10-inch pressure-treated boards to the concrete under the sill. That has worked — until now. The bottom sits snug to the frame, but the top is a half-inch shy of full closure. What is the best remedy?

S.C., Andover

A. Unfortunately, I think the door needs to be removed and reinstalled. It sounds as if the threshold may have bent and the frame has moved. The door frame needs to be re-squared and temporarily held until it is reinstalled using lateral braces. Then you can take the bracing off and reinstall the trim and finish as needed.

Q. My wife and I have a summer house that is not winterized and must be drained and left unheated over the winter. For the second time in five years, paint in one room of the house has peeled. It was far worse the first time; it affected nearly the entire ceiling. This time it was limited to wall areas above the windows close to the ceiling. The wall surface is lathe and plaster. On the outside, the porch roof meets the house wall at just about the same place as where the paint is peeling inside. There is no insulation in the walls. I don’t want to repaint each time this happens. I know it must be moisture-related, but I don’t know how to prevent it. Any suggestions?

SCOOTER

A. Often this is caused by poorly insulated areas losing heat in the winter and the resulting condensation causing interior paint failure. However, that is probably not the case here, as you shut everything down for the winter. I suggest looking at where the roof connects to the house directly over the problem area. Any place a roof connects to the house can be a leak point. The flashing, roofing, and siding need to be installed properly and in conjunction with one another. While up there, check the main roof above that spot to make sure something isn’t starting farther up.

Mark Philben is the project development manager at Charlie Allen Renovations in Cambridge. Send your questions to [email protected]. Questions are subject to editing. Subscribe to our free real estate newsletter at pages.email.bostonglobe.com/AddressSignUp. Follow us on Facebook, LinkedIn, Instagram, and Twitter @globehomes.