Camo Your Cracks

By Robert G. Kenel, Sashco, Inc

Checking is a natural occurrence that occurs in wood as it dries and acclimates to the surrounding atmospheric conditions. There are some things that can help reduce the effect of checking. Radial checking is the most common. That’s when the log shrinks as moisture is removed. To give you a better idea of how that looks. Picture the growth rings of the tree as a length of rope. It breaks as the wood dries. Know think the length of rope, it will shrink in length and get shorter. The longer the rope the more it more it will shrink. As these checks occur some will be bigger and others smaller as the logs reach specific gravity (G). You can see more in the ICC 400 Log Standards section 302.
Those checks can be seen exterior and interior, horizontal and vertical. While some see them as part of the log, others find them very displeasing. Besides the appearance there are some things that need to be addressed when checks are on the exterior of a structure. Foremost, upward facing checks are like gutters, collecting water in all its forms. This water becomes trapped and is absorbed in the wood fibers. It then starts to decay the wood internally where it can not be seen. Even if the logs look fine on the exterior, stain and sealers are doing their job. The hidden damages can cause expensive log replacement

Bigger checks of 1" or more I like to cut out a taper in the check. Using a small saw, I use a small electric chain saw. In which I cut tapers within the check making sure to go all the way to the very ends of the check. This is important as you can not caulk or seal those small ends properly. I do this for two reasons. One, to make a space for the wooden wedge I cut to fit the check. Two to cut out all the splinters to create a good fit for the backer strips required before caulking. On the job site I will use a 2X and circular saw set at angle to cut the wooden wedge. These I like to make a bit bigger so they extend beyond the log. That way I can grind off to fit. I fill the checks with either powder or liquid borates using a squeeze bottle. Like from a dish soap of ketchup bottle. I use glue to adhere the wedges. A good all weather adhesive I use is UltraTech 0770 ADA by Loctite. After the wedge dries is fully dried, grinded down and sanded. I can then match the stain and finish as needed.

For checks that do not need wood, proceed with the same method but use backer strips that fit the check. They come in many sizes. The use of backer is very important as it creates that all important two point adhesion that bonds much better and allows the product to stretch properly. If backer is not used product could pull from the wood and there is no mid point of expansion to stretch. Follow the curves of the check with the saw and backer. Again, don’t forget the borates. A proper backer in inserted in the check is 1/4'” – 3/8” below the surface of the face of the log. This gives a depth that will hold a good amount of caulk, but not wasting by using to much. Tool using water mixed with a little dish soap. You can use a small brush with hair or foam. Wipe any excess off with a rag wiping in the same direction each time. I like using caulk designed for applications I am doing. Textured products like Conceal have grits that make it much less noticeable when dry. Other caulks are very smooth, and wood is not so much. Colors change as they dry so always do a test area first. Stain can also be applied over these areas after proper curing.

Reprinted from 2019 GLLCA newsletter.