Wood Filler for Repairing Rotting House Support Beams

Is Filler the Right Choice?

• First, you must determine the extent of the damage to the support beam. Wood rot is not always visible on the surface. Gently knock the beam with a hammer. If you hear a hollow thump in several locations, it is an indication that the wood is rotten through the core and must be replaced. If the support beam is visibly rotten but only in a portion of the beam, wood filler can be used.

Preparing the Support Beam

• All of the rotten wood in the support beam must be removed. Failing to do this will result in future rot. This process will also help you determine the extent of the damage to the wood. Once all of the rotten wood is removed, the beam should be completely dried out. Then apply an epoxy sealant to protect the interior wood from future rot. This sealant must be allowed to dry completely, usually for at least 24 hours before the filler can be used.

Using the Filler

• Wood filler for this purpose comes in a liquid form that is sprayed into the cleaned out area of the beam. Care must be taken to ensure that the filler gets into all of the newly cleaned out areas so that the beam will be structurally sound. In some cases, it may take two or more applications to entirely fill in all of the areas. It is better to take your time and do this project right to ensure structural stability.

Protect Against Future Damage

• Once the filler has cured and is completely dry, sealing the exterior is a vital step. This will help prevent future wood rot in the rest of the beam and protect the filler. If the support beams are in a basement and out of sight, a clear epoxy sealant can be used. If the beams are visible, a regular latex paint can be used to cover over the filler and seal the wood of the beam.