The Rot Doctor


Subject: barn beam repair
Date: Mon, 19 Apr 1999

I am looking for a material to fill a rotten barn beam. My construction company has been contracted to reinforce a barn beam in a local historical building. Upon inspection of the site we found another beam in the barn that is in need of repair. it is approx. 8" x 8" and almost hollowed out from the top in. We need some sort of strong filler material that can be applied 6" to 7" in thickness. To completely repair the beam an estimated 5 gals of material is required. If you have a product which may work in the circumstance please notify us by E-Mail. Thank You.

Dave E.


My suggestion, based on similar projects, would be to first treated all rotted and adjacent areas with CPES (Clear Penetrating Epoxy Sealer). To us, this is an absolute, no matter what your second step might be (filler or wood replacement). CPES greatly restricts the rot problem, and restores strength and structure to any remaining rotted wood. If you don't treat with the CPES then you will always face the risk of the rot returning under the new wood or fill. This has been the approach taken for years by the people responsible for repairing and preserving the San Juan Baptista Mission and Hearst Castle in California.

CPES is a penetrating epoxy, about the consistency of diesel fuel, mixes 1:1 and can be either sprayed (with the nozzle/tube pick-up type of sprayer, periodically cleaned with epoxy solvent) or bushed into place with large throw-away brushes. The wood should be allowed to absorb all it possibly can. About 5-7 days are then required for carrier solvent evaporation and epoxy cure.

For subsequent fill you have a choice of two products, either of which are epoxy based, extremely strong, and bond at the molecular level with the CPES-treated wood. Our Epoxy Filler cures hard in 24 hours, and reaches full cure strength in about a week. It dr6ies off white and can be sanded. An alternative, if appearance is an issue, is to mix sawdust with our Layup & Laminating Resin and slow-pour or fill it into place. This dries VERY hard, is difficult to sand, but comes closer to retaining the look or the original wood. Both the filler and the resin are formulated to be slow-curing (allowing you plenty of time to get the material in place) and to bond at the molecular level with the CPES-treated wood.

All materials are in stock and we ship the same day as ordered. Get back to me if you have further questions.