How to Choose the Right Log Home Sealant

Caulks and specialty log home sealants are used to keep air, water, and insects from getting into your home.

The most important decision you will make is choosing the right sealant for your log or timber home.

Many sealing problems are attributed to the caulking material itself, and most often the proper sealant was not used for the job. It's easy to run to the local big-box home improvement store and pick up some all-purpose caulking, but therein lies the problem. 

There are six types of caulks: butyl, oil-based, ethylene vinyl acetate, urethane, silicone, and acrylic/latex. All are designed to do a specific job, and none are suitable for every application.

Caulking vs. Sealants

The most frequent mistake made by log home owners is choosing a silicone caulk. Silicone-based caulks are excellent for many applications, but they do not work well on wood. Silicones are formulated for use on non-porous surfaces like metal, plastic, or glass. However, wood is porous, and silicones do not adhere to either damp or dry wood. In addition, silicone caulk is difficult to tool and clean up and does not accept a stain or paint.

Presently, the most widely used products are acrylic/latex sealants. Although they are suitable for a wide variety of applications, their quality depends on the specific formulation and manufacturer. And that is where Perma-Chink Systems comes in. The deficiency in these caulks is they are not designed specifically for log and timber homes. 

log home sealants

Premium acrylic/latex sealants such as Perma-Chink, Energy Seal, Check Mate2, and Woodsman are manufactured from high-quality components to perform specific tasks. They are more expensive than a tube of general-purpose caulk, but they are formulated for excellent appearance, high performance, and ease of application. These sealants are made to be long-lasting and durable for the ultimate in wood care for decades.

Apply New Sealant Over Old Caulking? – NO!

An application of new sealant over old, failed caulk is rarely a good idea, even if it looks like the caulk still adheres to the wood. It may take a little more time, but old caulk should be removed for several reasons. If the caulk no longer adheres to the wood, it may be because moisture got under the caulk creating decay. Old caulk must be removed to properly treat and seal the wood substrate.

Newly applied sealant can only work if it is applied to a clean, sound wood surface or a compatible stain. So, if you want to use the old caulking as a backing material, you can apply a new sealant over the surfaces to adhere to a clean wood surface beyond where the old caulking reached. Otherwise, you should remove the old stuff.

Removing Old Caulk Between Logs

The right tools can make the removal process easy. Remember the old church key used to punch a hole into soda or beer cans? It is a handy tool to scrape out old caulk. Hook knives also work well. If the old caulk is silicone-based, you can usually remove it with your fingers. Always inspect failed caulk areas for evidence of moisture. If the wood is damp, these areas should be properly treated before a new sealant is applied.

Sooner or Later? When is the Best Time to Seal Your Log Home?

If you are doing other work, a decision to make early in the process is when to apply your sealants. This decision might have some bearing on which sealant to use. One consideration is that some sealants take a stain much better than others.

Smooth-surfaced sealants like Check Mate 2 do not stain as well as textured sealants like Energy Seal. If you are planning to apply sealants to your log walls first and then stain afterward, Energy Seal is your best choice.

Usually, the best time to seal logs is after the Lifeline stain has been applied. The log surfaces are fresh and clean and whichever Perma-Chink Systems sealant you select will adhere to wood surfaces stained with Lifeline. If you are going to use a topcoat like Lifeline Advance for exteriors or Lifeline Acrylic for interiors, we suggest that the topcoat be applied after the Energy Seal. This gives the most even appearance over the entire wall. However, if you want to hide the sealant and want a seamless appearance, apply Energy Seal before you stain.

log home wall chinking

Now let us look at various caulking applications around a log home and select the right product for each job.

Sealing Door and Window Frames

When sealing around window and door frames you have several options.

For either new or older log homes, we recommend Energy Seal since it has outstanding elongation and adhesion. This means that as your home settles and shifts, Energy Seal stretches to maintain its bond to the wood. It is available in 12 different colors and since it is textured, it will take the color of the stain.

On chink-style homes many people want the sealant to match their chinking. If that is the case, Perma-Chink can be used to seal around window and door frames, too.

Checks and Small Gaps in Logs, Log Corners and Log Ends

Upward-facing cracks and checks in logs should be filled with Check Mate 2.

Otherwise, they collect water that can lead to decay and insect damage. You need not worry about checks on the bottom half of round logs unless they penetrate through the log wall. Choose a color that is closest to the color of the stained logs. If checks are more than ¼ inch wide, stuff a length of backer rod into the check to about 1/4 to 3/8 inch below the surface before filling it with Check Mate 2. The Check-Kit has both backer rod and convenient applicator tubes. For more instructions on how to seal checks in logs and log siding click here

Sealant Application

One of the most common mistakes made when sealing logs is to fill deep gaps or checks with the sealant material. Quality sealants are made to stretch and elongate with the movement of the joinery. When a sealant is applied too thickly, it loses its ability to stretch and may separate from the wood.

A good rule of thumb is that the thickness of the sealant should be approximately 1/2 the width of the gap you are trying to fill. However, sealant joints never need to be more than 3/8 inches thick. So, how do you fill a large gap?

If you are trying to fill a void behind a window frame, for example, Log Gap Cap foam is the product to use. You can also put backer rod into gaps. See step-by-step instructions here.

The space left after the installation of the backing material is called the "caulking well." This well should be approximately 1/4 to 3/8 inch in depth, regardless of the width. This space is what you fill with sealant. Some sealant applications have geometries that do not allow for these “textbook” conditions. But, whenever possible, adhere to these specifications for the highest performance seal.

For filling in large voids or gaps, urethane foams are an excellent choice. However, many foam systems have a high expansion ratio which forces foam out of the void you are filling. It is difficult to remove. If you are unsure about your backing material, check with Perma-Chink Systems before using it.

Tips On Applying Perma-Chink and Energy Seal

Some people think that Perma-Chink and Energy Seal is just like any other caulking product on the market, so they apply and finish it with the same methods. Typically, silicone caulking can be smoothed just by running a damp finger along the bead of caulking. Using that method with Perma-Chink or Energy Seal will net you disastrous results. To get a smooth, clean finish, spray the sealant liberally with water then tool it with a metal spatula or similar. It's counter-intuitive to apply water to smooth it, but it's the best way. Unlike smooth caulking, the texture in Perma-Chink and Energy Seal needs more water to maintain a smooth finish. And it'll be much, much easier.


Remember, hot air that gets into your home in the summer and cold air in the winter increases your energy bills. Water penetration can cause decay and insect nesting. One of the best ways to keep insects out of your log walls is to eliminate the openings where they get in. Properly selected and applied sealants are among the best materials for protecting your home. Use the right sealant for the job for years of protection and comfort.

Call 1-800-548-3554 to request a copy of the "Log Home Sealant Application Guide" for more detailed information, or click here.

Last modified on Friday, 02 June 2023 16:26