Why do wooden doors expand?

Wednesday March 17 2021

Monitor your doors regularly to rule out expansion. PHOTO/tony mushoborozi

By Desire Mbabaali

A few months after being installed, my wooden doors started expanding more than the door frame. The doors could no longer close, and were pulling away from the design folds, exposing unpolished wood.


According to Emmanuel Kigozi, a carpenter, the cause of expansion of wooden doors is water. He mentions two possibilities: “First of all, if one buys a door but the wood from which it was made did not dry properly during the manufacturing process, it is likely to expand,” he says.

This is because wood swells or grows bigger when it has a lot of moisture and shrinks when it is dry.

The other possibility, he says, is that by the time the door was installed, it could have been dry, but it took in a lot of moisture as time went by.  So, it started swelling disabling itself from fitting into the door frame.

When asked what causes the moisture to get into the wood, Charles Luyima, a carpenter does not differ from Kigozi and shares two major reasons.


To start with, weather has a big role to play in all this. When it is cold and rainy, (especially for a prolonged time) there tends to be a lot of moisture in the air and wooden doors are likely to absorb it.

The same can also happen if someone’s house is in a wet place, with moisture locked in the walls and floor, or if the door is in a place that exposes it to water such as the bathroom or outdoors. In such moist conditions, if the door was not painted and/or has a crack that exposes it to moisture, then swelling can be expected.


To mitigate these challenges, Cliff Muwanga, a carpenter, says one needs to ascertain what the cause is and then solve it.

“If it is about the weather or wet conditions in your location, there is little you can do, but paint the doors to make them more resilient to moisture.”

Alternatively, doors can be replaced with doors of stronger wood such as mahogany that is more resilient.

“If the door was installed before fully drying, you need to wait for it to dry before calling a carpenter to reduce it to fit into the frame and repaint it on the sides to prevent moisture absorption,” Muwanga advises.


Kigozi tips that when buying wooden doors, one needs to ensure that it is thoroughly dry to avoid any cases of swelling after it has been installed.

Buying from a trusted furniture mart or having your carpenter help you choose a door can be helpful.

Buy doors of resilient wood like mahogany, especially if it is to be installed in moisture prone areas like the front door.

Avoid spilling water directly onto the wooden door as much as possible. For maintenance and cleaning, only use a slightly damp cloth instead of wetting. Often vanish when colour pales to make it more resilient to moisture.