What to do After Borate Treatments

The following are guidelines to follow after performing a borate treatment to your log home.

Shell-Guard® RTU

Washing – Never wash down a wall within five days of application. It’s really best to wait at least seven days. In practice, there are very few occasions when a wall treated with Shell-Guard RTU needs to be washed at all. As long as the first coat of finish can be applied within seven days of application, there is no need to wash it down. If, for some reason, there is a delay in applying the first coat of finish or discolorations or white residue is present, then washing with water or Log Wash™ may be appropriate but under no circumstance should the wall be washed less than five days after the Shell-Guard RTU was applied. Too much of the active borate will be washed away.

Staining – An application of Shell-Guard RTU almost always dries enough to stain the wall the day after it was applied. There is rarely a need to wait more than one to two days after a Shell-Guard RTU application to apply the first coat of finish. Occasionally early morning dew may make the wall a bit damp to the touch, but once the sun comes out and the wall dries, the finish may be applied without affecting adhesion. If, for some reason, application of the first coat of finish is delayed for several weeks or even months, that’s okay. Once the borate gets into the wood it is very difficult to remove, even if it gets rained on for several months. In this case even pressure washing won’t remove enough of the borate to matter.


Washing – Never wash down a wall within three days of application. Again, it’s best to wait at least seven days but in typical weather conditions most all of the water accompanying the borate will have dried within three days, and once the water dries, the penetration of the borate into the wood ceases.

If white deposits are present on the surface, a light misting with just water should be tried first and if, when the surface dries, they are still evident, then try washing the wall down.

Staining – Like Shell-Guard RTU, there is rarely an occasion that an Armor-Guard® treatment is not dry enough to stain the very next day.

Shell-Guard Concentrate

Washing – The use of Shell-Guard Concentrate has created much of the confusion relating to washing borate treated walls. If Shell-Guard Concentrate is used, it must be allowed to dry at least two weeks then washed down with Log Wash before staining. The two week wait and washing is not optional, it’s mandatory. We used to say that if it was dry to the touch, it was ready for staining, but we found that it could appear dry one day and be damp enough the next morning to create stain adhesion problems.

The other thing we’ve found is that there are some types of molds that thrive on the glycols contained in the Shell-Guard Concentrate. If the treated surface is not thoroughly cleaned of these mold spores, there is a chance that mold spots can develop under the finish.

Remember that although borates are great for eliminating and preventing wood decay fungi, they are not effective in killing or averting all types of surface molds.

Staining – The first coat of finish should never be applied over a Shell-Guard Concentrate treatment without first washing down the wall with a Log Wash solution. One of the glycol components in Shell-Guard Concentrate tends to stay on the surface and can create adhesion issues with the stain, or even Perma-Chink® or Energy Seal™ for that matter. Just remember to allow at least two weeks after the Shell-Guard Concentrate application before washing the surface.