The Rot Doctor


Subject: What about wood and brick?
Date: Tue, 02 Nov 1999

We have just had a significant amount of termite damage repaired. One of the rooms is a patio that was converted into a sun room and there are several places where wood comes in contact with bricks or concrete. One example is where the plate contacts the foundation. Much of this wood was not replaced; but, was reinforced with new wood. I plan to go back over the contractors work and treat the wood as you suggested to another inquirer. Do you have any additional suggestions for the areas where the masonry and concrete contact the wood? The brick is soft Mexican brick.

Your plan is a good one, because the chances are the termites will return and you want to create an environment that they do not find attractive. I'm sure you know this.

CPES (Clear Penetrating Epoxy Sealer) will migrate a long way in and around wood joints and crevices. The key is to keep applying it as long as the particular location will absorb it. It is crucial that you allow it to soak into all joints, cracks, wood end-grain, for this is where the insects like to start. The CPES will easily penetrate between the wood and the brick, and will to some extent soak into the brick surface and harden it as well.

If you use a borate, as you suggest you will, then be sure to use the pure disodium octaborate tetrahydrate, which is sold as Tim Bor or by Sashco as Penetreat (in 25 lb buckets). You just mix with warm water as per instructions and spray on the wood. After the borate treatment, allow at least a week and preferably two weeks for the wood to dry before applying the CPES. Don't use the borates that are mixed with glycols. The glycols will inhibit the penetration of the CPES and, in our opinion, do little else that is good for the wood.

Be cautious is using CPES in enclosed environments. Cross ventilation with a fan is desirable, and unless there is free flow of open air then we suggest you wear a mask with filters capable of filtering organic solvents. Vinyl gloves are useful as well.

I also plan to replace some of the lower redwood siding. It is 3/4" thick and I plan to borate it and "paint" it with Clear Penetrating Epoxy Sealer (CPES) on both sides before installing. My goal is to eliminate as much moisture as possible; because, the termites need it to survive.

One good coating of the CPES here is all that is needed. Actually, a coating on the end grain areas inside surfaces of the planks is where it is most needed. Again, allow a couple of weeks after the application of the borate solution before the application of the CPES. CPES will "color" the redwood to about the same extent as a coat of flat varnish, i.e., darken it slightly and highlight the grain. I mention this just in case exterior appearance is a factor. As suggested above, you could eliminate this problem by just applying the CPES to the inside of the siding and the end-grain areas. The termites will never attack the wood directly from the exterior. They will want to work in between the boards, and this will be protected.

This our second bout with termites. Any recommendations or suggestions would be sincerely appreciated.

Thank you,
Jim C.


Your plan is sound and calculated to reduce to the lowest level the chance of termite infestation these areas. The CPES will actually lock in the borates, which under normal circumstances will over time leach away with moisture.

Come back if you have additional questions and we'll do everything we can to be helpful.