Borate Treatments for Log Structures
Let’s talk for a bit about borate treatments for your log home. If you’ve never heard of them, you are probably asking “why would I want it?”. Well, do you hate the thought of termites of all kinds eating at your house? How about carpenter ants, old house borer beetles, powder beetles, and post beetles? Finally, how about brown rot, white rot, mold, mildew, and other wood decaying fungi? I didn’t think so. You know, borates can and do kill all the above insects and organisms. Sound a little more interesting now? Let’s get started.
What is borate? Disodium Octaborate Tetrahydrate, or DOT (no not THAT DOT, this one really works!), is a borate salt compound that is formed from a union of boric acid and borax. This is the most common form of borate used in log home treatments. Various name brands of water-based borate solutions are available, such as Armor-Guard, Tim-bor, Penetrate, Board Guard, and others. There are also several glycol-based solutions, such as Bora-Care and Shell Guard. These borate applications are generally used in crawl spaces and attics..
How do borates work? Borates are toxic to both insects and fungus species. One way the borate works is that it disrupts the enzyme system of the insect and destroys the micro flora in the stomach of the insect, thus disallowing food digestion. Borates also affect the enzyme system of fungi. Finally, the active ingredient is a contact toxicant to fungus.
How do I apply it? First of all, it’s important to realize that the borate needs to soak into the wood as far as possible. There can be no stain or other finish on the wood when the borate is applied. The best ways to prep for borate is to media blast the wood, making it even more porous. Every borate manufacturer has different methods of application and a special focus on what their product will do. Let’s look at them as groups, and not brand names.
Second, there are water-based solutions. You’ll buy these as a powder in some size pail. So many scoops to the gallon, and again, you are spray applying these onto the wood surfaces you want to protect. Protection is good near the surface, about a quarter inch or so. A hard rain will wash it off, which is why you need to coat the wood soon after with a stain/sealer.
Third, there are borate rods. Cobra Rods and Impel Rods are the most popular. These rods are made for high-risk areas of your house, such as log ends, that get a lot of splashing water on them, or protrude out past the overhang. A hole is drilled, the rod inserted, and a plug tapped into place. If the log gets wet, the borate will diffuse into the surrounding wood, protecting it from rot.
Finally, taking into account that many borate treatments are applied specifically for the purpose of the protection of log homes, which will require a sealing stain treatment anyway to lock in the borate. There are a few companies working on a penetrating oil based application of borate, which will allow other ingredients such as base color pigments to be introduced deep into the wood as a conditioning step, after which a positive curing top coat is applied to “lock in” the borate.
While borate solutions are very good for pretreatments before staining the logs on your house, they only help prevent mold and mildew from forming UNDER the stain layer. They do NOTHING about mold or mildew on the surface of the stain. Only a periodic cleaning will remove that mold or mildew, and borate treatments should never be viewed or presented to a consumer by a restoration contractor as a way to avoid regular maintenance.
West Coast Restoration LLC
Bill Finley, Principal
757 Cedar Creek Lane
Bellingham WA. 98229-1900