How to Fix Rotted Wood with Epoxy - This Old House- how to seal rotted wood ,In this video, This Old House general contractor Tom Silva saves a rotting window with a two-part epoxy filler. Steps: 1. Use trim router or rotary cut-out tool fitted with a V-shaped bit to grind out all the rotted wood. Stop when you reach sound, solid wood. 2. Use aHow to Fix Rotten Wood on a Roof | Hunker23/8/2018· Pull up the felt paper underneath the shingles. Working your way up the roof, expose all of the rotted wood. Leave the next course of shingles intact by carefully removing the second set of four nails. During a reroof, start at the peak of the roof and remove all shingles, prying them up with a pitchfork, working your way down the roof.