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Tips on repairing wood rot

Patches can be used to fix some damage. But often the homeowner must buy a new frame.

Q. My question is about a door frame with water damage. I have tried to repair it three times now, using “fake” wood in two instances and cement the last time. The new rotten wood is above and around the cement. Thinking that water/moisture might be coming in through the vinyl siding, I filled the open space last summer just above the door frame. I am at a loss as to where the moisture is coming from, affecting the left and right side of the door frame. I have been in this house for four springs and summers now, and it looks like the cracking of the wood occurs sometime during or after the winter. My first two attempts at fixing this looked OK during the summer and fall. Last year, I just covered it up with tape. I am at loss on how to proceed at this point. Heating is achieved through forced hot water baseboards. The ones closest to the door frame are some distance away from the wood frame, and there are no signs of leakage.



A. I looked at your pictures, and the door jamb is long past useful service. It’s time for a new and improved door. Next time put some dead-light safety-glass panels over the sidelights. You will gain added energy savings as well as protect your sidelight jamb from the elements.

For future reference: In my experience, wood filler, putty, and Bondo simply do not work for long in this situation. When I have rotted wood, I always cut out the damage and install a wood or Dutchman patch. Dutchman patches are known primarily in carpentry, furniture-making, and masonry. A Dutchman is a piece of wood or stone used to repair a larger piece, shaped such that it fills a void.

When performing a Dutchman repair, I like to use western red cedar or mahogany for the patch and seat it in marine epoxy. Both wood species have inherent insect- and rot-resistant qualities. I reached out to one of my painter friends, Bill Cooper from William F. Cooper Painting in Concord. Like me, Bill thinks that most wood-repair systems eventually fail if they are in areas that get wet (usually the reason why there is rot in the first place).


According to Bill, the trick is to cut back at one to two inches more than the soft or rotted wood so the epoxy has solid wood on which to adhere. One thing to consider is what type of wood you are trying to save. A lot of it is not worth saving and should simply be replaced with a rot-resistant wood like red cedar, Spanish cedar, or mahogany. Bill warns against using Bondo: It is a polyester resin and does not hold up as well as the marine epoxy systems. Done right, there will be zero evidence a repair was made once it is painted.

Rob Robillard is a general contractor, carpenter, editor of AConcordCarpenter.com, and principal of a carpentry and renovation business. Send your questions to homerepair@globe.com or tweet them to @globeaddress or @robertrobillard.