If the caulk has lost some of its adhesion, it may have allowed moisture to seep in under it, possibly creating decay. The old caulk must be removed to properly treat and seal the area, so it does not happen again.
The old caulk may have deteriorated due to age, decomposition, or the wrong type of caulk being used. We often find that silicone caulks were used to seal wood joinery or checks. Although silicone caulk does a good job sealing glass and tile, it does not adhere well to porous materials like wood and deteriorates rather quickly when exposed to direct sunlight.
Butyl rubber caulks and oil-based caulks may out-gas, creating blisters in freshly applied Energy Seal, Woodsman, or Check Mate 2. Inexpensive hardware store caulks harden with time and will pull away from adhesion point surfaces. No matter what type of caulking was previously used, if it is not removed, the adhesion of Energy Seal, Woodsman or Check Mate 2 to the wood will only be as good as what’s left in the old caulk.
All sealants manufactured by Perma-Chink Systems are formulated to have excellent adhesion to wood and other building materials. They contain high-quality acrylic resins to insure that they do not lose adhesion, color, or elasticity when exposed to the elements for decades.
There are some tools that can help make old caulk removal easier. Hawk-billed or linoleum knives are great tools for scraping off old caulk. If the old caulk is silicone-based, it can usually be peeled off by just pulling on it with your fingers or needle-nosed pliers.
Check caulked areas that have failed for evidence of moisture. If the wood has been damp for an extended period, these areas should be treated with a borate and allowed to dry before Energy Seal, Woodsman, or Check Mate 2 is applied.
Energy Seal, Woodsman, and Check Mate 2 work best when applied to bare wood or over stains or topcoats manufactured by Perma Chink Systems, Inc. If it is applied over an existing old caulk, you run the risk of adhesion failure and your time and money will have been wasted.
Note: Please remember that Energy Seal, Woodsman, and Check Mate 2 should always be used in conjunction with Backer Rod wherever possible.