Finishing a wood exterior door.

Dana asked 10 years ago

We have a knotty alder front door. It is south facing w/ a short overhang which does not do much to protect it. We are replacing it for the 3rd time due to cracks (thank goodness we’re not paying for it). The door is probably sealed with a urethane resin or something similar. We really don’t want to get a fiberglass door so we are trying one more time w/ wood. Do you think if it is finished with a marine/spar finish, it will be less likely to crack in 6 months? I would like this door to last a very long time. Any suggestion are most appreciated.

1 Answers
JT Creations, LLC answered.

A southern exposure will always result in a door which shrinks thereby showing cracks. But then so will a northern, eastern and a western exposure. Neither the exposure nor the door manufacturer is to blame. The door is assembled from boards of random widths and glued. As the moisture leaves the wood, the wood shrinks. Now you can see cracks through the door. One solution is to purchase a door with tongue-and-groove boards so the light will not be visible through the door as quickly. If you use a wood door you will inevitably have cracks visible. No amount of varnish will stop them.