Wood takes on and gives up moisture as the air around it changes, and it swells and shrinks when it does. That movement can warp, crack or split a wood garage door, especially if the finish has worn thin. Keep every surface sealed, inspect the door every 12 to 18 months and stop using it if it rubs or binds.
Why wood moves
The USDA Forest Products Laboratory explains that wood changes size as its moisture content changes. Below a point called the fiber saturation point, wood swells as it gains moisture and shrinks as it loses it. The handbook adds that this shrinking and swelling can result in warping, checking and splitting.
Wood in service also follows the air around it. Its moisture content is a function of both the relative humidity and the temperature of the surrounding air, and the changes are gradual. Seasonal swings move the whole door, while daily swings mostly affect the surface.
Why the grain matters
The handbook says tangential shrinkage, across the growth rings, is about twice as great as radial shrinkage. A panel cut one way moves more than a panel cut another way, and a long door section is not uniform. That is one reason one panel can bow while its neighbor stays flat.
Coatings help but do not stop the movement. The handbook says moisture content changes can be retarded, but not prevented, by protective coatings such as varnish, lacquer or paint. A sound finish slows the swings. A worn one lets them run.
Signs your wood door is moving
- Gaps opening at panel joints, or a seam that was tight now showing light
- A bowed or cupped panel that no longer sits flat with the sections beside it
- Hairline cracks along the grain, or splitting near the hinges
- A door that rubs the track or the weatherstripping in one season and not another
- Peeling or dry-looking finish, especially on the sunny side and the bottom section
Warping and your hardware
A warped section can twist the door in the track and add load to the springs, cables and opener. Pull the red release handle, do not keep running the opener, and do not adjust any spring or cable. See garage door repair.
Loose hardware is a related sign. DASMA says that if any hardware appears loose on a wood door, a trained door systems technician should inspect the attachment points, because the screws hold in the wood itself.
Upkeep that slows the damage
DASMA says to inspect, maintain and clean wood doors every 12 to 18 months, or as the manufacturer specifies, and to look for fading, peeling, chipping and buildup. Fill, caulk, sand and recoat areas where the wood has shrunk or expanded.
Finish all six sides of each section before installation, so no bare wood takes up moisture. The bottom section wicks up water and typically receives the most moisture, so keep its finish and its seal in good order. Clopay suggests repainting its wood doors every 1 to 2 years, and your own door maker's care sheet sets the schedule for yours.
Repair a section or replace the door?
A single warped or cracked section on an otherwise sound door can sometimes be replaced or repaired, if the model is still available. A door with several bowed panels, soft wood or a worn-out finish costs more to chase than to replace. Real wood doors are quoted in an approved range of $3,500 to $9,000 and up, and a quote should list the wood, the finish and the hardware. See new garage doors, including wood-look composite doors that move less.
Who to call
Emil Garage Doors repairs garage doors, springs, cables and openers and installs new doors in Texas, including San Antonio, Waco and Dallas. Send photos of the gaps, bows or cracks with your details and we book the soonest visit.
Questions people ask
Does heat warp a wood garage door?
Wood moves with moisture and temperature. According to the Forest Products Laboratory, the swelling and shrinking can cause warping, checking and splitting. A sound finish slows it.
How often should I inspect a wood garage door?
DASMA says every 12 to 18 months, or as the manufacturer specifies.
Can I keep using a warped garage door?
If it rubs, binds or hangs crooked, no. Disconnect the opener with the release handle and call a technician, because it can strain the springs and cables.
Is a wood-look composite door a better choice in a hot climate?
It can move less than real wood, but ask for the maker's care sheet and warranty for the exact model before you choose.
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Sources
- USDA Forest Products Laboratory: Wood Handbook, Chapter 4, Moisture relations and physical properties of wood (dimensional stability, warping)
- DASMA: How to inspect and maintain wood garage doors (inspection interval, finish, bottom section)
- Clopay: How to restore faded garage doors (UV fading, wax, wood repainting)