We did a renovation about 5 years ago, and installed wood doors for our front and side doors. We’ve noticed what looks like dirt on them, but it won’t wipe clean, so I’m afraid it’s mold and going to get worse with time. What can we do to fix this? What caused it in the first place?
The finish has weathered off the horizontal, probably because the grain is trapping moisture as opposed to the verticals. This is only speculation because the wood pins indicate a more high end fabrication style.
The entire door is showing weathering from top to bottom but the base is the most affected.
I would not be surprised, given the construction, that the individual pieces were stained and then assembled and a final clear coat applied afterwards.
You should consider stripping, lightly sanding and refinishing the entire door to maintain a uniform appearance. Use a UV stable polyurethane for your final finishing coats.
Failing that, the stops and horizontal should be re-finished. A Dremel (multi) tool with a sanding surface will help you with the curves on the stop. Tape off the verticals with duct tape to preserve the verticals. You will have to test the surface with several stains to find the match that will not be too obvious. Finish with UV stable polyurethane.
The door(s) are subject to weathering. Consider adding some overhead protection over the affected openings.
