Soft, rotten or severely damaged wood can be repaired with a combination of a penetrating liquid epoxy and a good wood filler.
Step 1: Before making any repairs to rotten wood, identify the cause of the wood rot and repair it. Repairing damaged wood without first addressing the aggravating factor will only result in the need for additional repairs in the future.
Rotten wood is often the result of improper water drainage. Check gutters, drip edge and other water diverting devices to assure they are working properly. Exterior window ledges should slope away from the house to allow for proper drainage. Downspouts should direct water away from the home. Trees, shrubs and other vegetation should be a minimum of 12 inches away from the home to allow for proper air circulation and to discourage insect infestation.
Step 2: Once the aggravating factors have been addressed, allow wood to dry completely before proceeding with any repairs.
Step 3: Clean away any loose wood and debris from damaged area. Trim back small irregular sections. When using liquid epoxy for repairs, drill several angled 1/8-inch shallow holes into the wood, but not through the wood for added penetration. The holes will function as small reservoirs for the liquid epoxy to gather in.
Step 4: For the best long-term results, choose a high-quality, two-part liquid epoxy such as Abatron’s Liquid Wood. Minwax Wood Hardener is a good alternative for less damaged areas. When using two-part products, follow the manufacturer’s instructions thoroughly, mixing up only as much epoxy as needed for the immediate project.
Step 5: Brush or pour the liquid epoxy onto the rotted wood. Allow the epoxy to puddle in the shallow holes. Saturate the wood completely and then allow it to dry.
Step 6: Once the liquid epoxy has cured and the rotted wood is hardened, fill the remaining gaps with a high-quality, two-part epoxy filler, such as Abatron’s Wood Epox.
Step 7: Wearing latex or vinyl gloves, mix equal parts of the epoxy components together until the product is a uniform color. Epoxy putties dry quickly, so mix small amounts at a time to avoid waste. Use your hands to work putty into small sections at a time, shaping the putty to resemble the missing wood sections as closely as possible. Once dried, epoxy putty can be sanded, drilled and finished just like real wood.