Dry rot in wood isn't something that any of us want to find, but it certainly does happen. Dry rot occurrs when wood has lost all or most of its moisture. When that happens, the wood becomes brittle and will crumble. Dry rot can also be caused by termite damage, as the termites will eat away at the pulp of the wood, causing it to die. Dry rot becomes dangerous when it is part of a load bearing structure, such as a wall or floor. You can repair dry rot in these structures. The following article will show you how to do so on a floor, but the method explained can be used elsewhere as well.
TIP: Because dry rot often happens when homes have high moisture problems, it's a good idea to check the house for fungus, mold and similar problems while you're dealing with the dry rot.
Step 1 - Clean the Dry Rot
One key issue dry rotted wood is the fact that it can spread over time. If the rot spreads, then the wood can completely rot and crumble. It will not have a chance at being saved. In order to properly repair a floor board that has spots of dry rot, it is necessary to remove the rotten wood from inside and around the site. Many people will say to cut it out and replace the plank, but all that work can be avoided if it is possible to save the wood.
Use a vacuum with an extension wand. Remove the brush so that you have straight suction with no interference. Insert the nozzle inside the area and suck up loose bits of wood. When you are satisfied, you can use the chisel and hammer to gently tap away the surrounding area. Dry rot will leave the wood very weak, so it should not take much force to remove the pieces. Once they are removed, use the vacuum again to remove any debris.
Step 2 - Fill the Hole
Once the area is clean, you can fill the hole. Wood putty is difficult to apply correctly because of the tube in which it is packaged. Other wood putty can be found in tubs, which are also difficult to use when trying to fill a void left by dry rot.
The simple solution is to use a pastry bag fitted with a plain plastic tip. Fill the pastry bag with the wood putty and twist the top so that the putty pools near the tip. Insert the tip inside the hole and gently squeeze the pastry bag. Doing so is the easiest and quickest way to fill dry rotted wood. You will be able to maneuver the putty in a way that is impossible with a bucket or tube. You want to overfill the hole so that you also seal the top edges.
Step 3 - Finishing
You do not want a mound of wood putty on your floor, so you will need to make it flush with the surrounding area. Wait for the wood putty to cure completely. Attach the sandpaper to a sander and gently apply pressure as you sand down the wood putty.