The Rot Doctor


Subject: repairs on a log cabin
Date: Wed, 19 Apr 2000

Dr. Rot
I do not believe there is any rot in the logs, because they seem quite solid. We would like to fill in the cracks. There is an 18 inch eve, and the logs don't seem to get wet at all. Thank you in advance for any help you can give us.

Hi Janis,

Okay. I'm happy that there are no signs of rot. It's fixable, but a hassle.

First, what you want to do here is protect the wood inside the cracks, so that moisture getting inside cannot be absorbed by the wood, which in turn creates an environment that fungi and bacteria find attractive. To do this, you just need to apply CPES (Clear Penetrating Epoxy Sealer) to the INSIDE of the cracks. This can be done with a brush, a turkey baster or a syringe -- or a combination of these application units. The CPES is put in and allowed to be absorbed by the wood, and you will want to keep putting it in as long as the wood will readily absorb it. If the CPES keeps disappearing into the wood, then that means it is finding open areas and these are precisely the areas you are trying to protect. How much CPES you would require is not predictable, because it depends on the number, depth, and absorbency of the cracks. You might start with a 2-gallon unit and see how far it goes. The wood should be reasonably dry during the application process.

You can apply CPES effectively on log surfaces as well, but you should be aware that after the CPES has been applied the log will no longer accept a stain in the same way that untreated portion of logs will. This is a problem for some people. The CPES itself will color wood to about the same degree as a coat of clear varnish -- slightly darken it and highlight the grain.

After the CPES application, the wood inside the cracks is pretty well protected, and the protection is more or less permanent. You could basically walk away from the project with a high degree of confidence.

However, if you wish to fill those cracks, then we'd suggest using a mixture of our Layup & Laminating Resin and coarse sawdust. The resin is mixed and the sawdust is added until you have a spreadable paste which can be knifed into the cracks. It will bond with the CPES-treated wood and form a permanent, basically waterproof fill. It is also VERY strong. You might want to use some masking tape on the crack edges to make the spreading process easier. After you mix and add the sawdust you'll have about 30-45 minutes (depending on the temperature) to work with the paste -- so, you only mix what you think you will use in that period of time.

Come on back if you have additional questions, or we can be of help in any way.