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Why Do Wood Doors Swell?

If your wood door appears a bit bigger than it used to be, particularly during humid seasons, it probably is. Local window replacement company Renewal by Andersen® of Long Island shares a close look at what makes wood doors swell, and how to prevent it.

Why Do Wood Doors Swell?

Wood fibers are naturally porous and can absorb large amounts of moisture, and tend to expand and contract dramatically from exposure to heat and cold. This is why wood needs to be treated before it can be used for building, and why wood stain or waterproofing has to be reapplied periodically. As wood doors expand, they push against the frame, which makes them difficult to open and close.

Some recommend removing the sash from the frame and sanding or planing the edges, but there’s a very small margin for error. Take off too much and you might end up with a large gap that would allow air leaks. Most manufacturers prohibit making such adjustments to doors and windows, as it might void the warranty.

Door Maintenance

Regular maintenance can help prevent moisture absorption and warping. Door maintenance differs depending on the door type, and what materials they’re made of. Painted wood doors will need to be scraped and primed before a new coat of paint can be applied. The process is a bit different with stained wood doors, since “bald” spots (areas where protective coatings have been worn off) are hard to spot. One way you can test for such spots is by misting the door surface using a water sprayer. The coating is good if the water forms beads. You will need a recoat if the wood absorbs the water.

Frenchwood® Patio Doors

Renewal by Andersen offers Frenchwood® patio doors, made with natural wood. We only use properly-treated wood to ensure stability and minimal warping. Our traditional French doors are protected by a factory-applied urethane base finish, while our hinged Frenchwood patio doors feature a composite exterior reinforced by glass fiber. Also, our Frenchwood gliding patio doors are protected by a rigid vinyl sheathing. These features help reduce swelling by protecting the doors from moisture absorption and temperature extremes.

Renewal by Andersen of Long Island is your leading provider of specialty windows. Give us a call at (631) 843-1713 or fill out our contact form. We serve customers in Huntington and nearby areas.


"I was very impressed with Renewal by Andersen. They showed up in time and we received several follow up phone calls as the installation was being done as well as the sales representative stopping by to check in on the installation. The delivery/ installer was very professional. I would highly recommend Renewal By Andersen."

February, 18

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