The Rot Doctor


Subject: Another Log House
Date: Wed, 05 Aug 1998

I have read your responses to queries about log rot and insect damage repairs. I have the same problem in my log home and would like some clarification. The epoxy/wood flour mixture you refer to-can you explain what specifically you mean?

It is a mixture to putty consistency of our Layup & Laminating Resin and wood flour or sawdust. In the case of a log home, sawdust would be just fine and cheaper than buying wood flour (note: wood flour is very fine sawdust from finish-sanding wood). Our L&L Resin has a longer pot life and cure time than the normal petroleum-based epoxies, which is why it is desireable for this application.

Is this the material that will show on the outside of the logs after they are treated with CPES?

It can, if it is used to close drill holes, fill cracks, etc. An epoxy filler is always to be desired, since it will bond with the epoxy impregnated wood. You could even add dye to try to get close to a color match. Once hard, it is VERY difficult to sand smooth, and it will not take exterior stains in the same way wood will. An alternative to closing the drill holes with the resin/sawdust, is wood bungs that have been coated with the CPES. The CPES will protect them from rot.

If people have hollow logs, we always recommend that they saw away the face of the log, treat the interior, fill it, and then replace the treated face-piece. It keeps the natural look.

And what about concrete? I like that idea, but again what will that look like on the outside of the logs?

We are ambivalent about concrete. People have reported using it to fill logs, because it is inexpensive. Its drawback is that it tends to attract moisture, but on the other hand the wood around it is CPES-impregnated and will never rot. It is also commonly used in old wood boat bilges without bad effect. Our boat, in fact, has about 1/2 ton of it in the stern.

The people who use it put it under the face piece, so the concrete isn't visible.

The way I understand it, I need to:
1. Drill and treat logs with CPES

Yes. However, the drill-and-inject method assumes that most of the interior wood is still there, even though rotten. This then becomes the "framework" for the CPES, which infuses it and then hardens. You can tell what's going on in the log when you drill. As long as you keep pulling wood, okay (it should be reasonably dry), but if you hit large gaps then you need to think about fillers and if the gaps are large, sawing the face off the log.

2. Fill large gaps with epoxy/woodflour (or concrete) mixture?


3. Finish with UV protectant/waterproofer


Thanks for your help.

You have the basic procedure down correctly. I hope my notes above are of some help. As far as we know, the CPES is the only product available that will truly penetrate and harden large masses of bad wood, and work its way to the bad-wood/good-wood interface, which is where the rot fungi are.

Let us know if we can be of further help.