How can I fill the checks and cracks in the logs?
First, it is important to realize that the most worrisome checks are those on the upper curvature of the logs – making them the most prone to collecting moisture, fungi spores, dirt and other contamination. Larger checks on the lower curvature – while not prone to collecting moisture – can still lead to air infiltration into the house and provide entry access to flies and other insects. It is also important to realize that for approximately the first 1-2 years – especially if the logs are relatively green to begin with – that the initial checks will continue to open up as the logs dry out. If this continual “opening up” is likely to be severe – which could cause any caulk or chinking to fail – then it should be understood that some sealant repair may be needed after the logs have come into moisture equilibrium with the climate of the building site.
Applying a penetrating oil like the Outlast Q8 Log Oil that penetrates deep into the wood can help prevent some of the checking. No waiting time is needed between construction and staining with this product. Customers who have used the Outlast Q8 Log Oil have even commented that smaller cracks and checks in the logs have shrunk or even closed up after applying this product.
For checks that are about 1/4” and larger in width (which are large enough to accept round backer rod), they can be effectively sealed with such products as Log Builder caulking, or, for a more textured appearance, Log Jam Chinking. It is always best to perform the following steps when sealing checks with caulking or chinking (starting, of course, with appropriate weather!):
1) Make sure there is no standing water in the checks to begin with (otherwise, there is a great risk of rot and premature sealant failure. Either remove the standing water or let it evaporate away.
2) As part of the overall application of a wood preservative, like Timbor or the Outlast Q8 Log Oil, to the surface of the logs, extra wood preservative should be applied into the checks that are to be sealed with caulk or chinking – then allowed to dry/cure prior to sealing.
3) It is usually best to apply the log home stain that will be used over the general surface of the house to the inner lips of the checks to be caulked or chinked – if the stain is compatible with the caulk and chinking to be used. Such a stain can act as a primer for the caulk or chinking and can greatly improve adhesion, especially when the walls are subjected to very wet weather. [Note: If the inner “lips” of the checks are dirty or significantly weathered, then these “lips” (i.e., the surfaces of the check which will be in contact with the caulk or chinking) need to be cleaned, down to bare, “sound” wood – in order to insure good adhesion of the stain and/or the caulk or chinking. Such cleaning can be accomplished several ways (including power washing and hand-sanding), but cob-blasting with a Sashco Kernel is the fastest, easiest and surest way to do the cleaning.]
4) Install the appropriate round backer rod, to the proper depth. [Note: The depth of the sealant bead should be approximately 1/2 of the joint width. This guideline will dictate how deep to press the backer rod into the check.]
5) Apply the caulk or chinking into the check with good pressure, forcing the sealant into intimate contact with the inner lips of the check. Do not just passively lay the sealant into the check recesses, which will have a tendency to not let the caulk or chinking properly “wet out” the surface – leading to poor adhesion.
6) Then, using a putty knife, shaped piece of wood, or a finger, “tool” the bead to further force the sealant into intimate log contact. While tooling, scrape the excess sealant from the sharp edges of the check and remove any material that may have smeared over the surfaces of the adjoining logs with a wet rag or sponge.