Chinking & Sealing

Sealants – Log Home Chinking

Chinking Basics

When logs are first cut, they are very wet. As they dry out, the logs shrink in diameter. The majority of the movement takes place in the first 12 to 18 months. However, seasonal moisture variations can cause smaller but continuing cycles of shrinking and expanding.

For years, chinking material did not adhere to the logs and did not have the ability to stretch and follow the movement of the logs as they expanded and contracted. Mortar chinking lasted longer than mud or cow dung, but it quickly cracked or separated from the logs. Then, in 1981 Perma-Chink Systems invented the first pure acrylic polymer-based synthetic chinking.

The advantages of this revolutionary polymer based chinking material are many:

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Adheres very tightly to the logs (even when they are wet)

Is an elastomeric allowing it to stretch and contract with the logs without breaking or separating


Colored and textured to look just like conventional mortar chinking


Available in several different colors


Easy to apply and can be troweled to just about any thickness or width

Lasts for the life of the structure
Very little maintenance, periodic cleaning

Thick vs. Thin Chinking

Different log building styles lend themselves to different chinking appearances. Square logs with dovetail corners have a dovetail that interlocks the logs at the corners. As a result of this geometry, the chinking gap between logs can be 3 to 4 inches wide. Some square logs, however, have chinking gaps 6 to 8 inches and more.

Round logs with saddle notch corners typically have one full log sit directly on top of another, yielding a gap of 1.5 to 2 inches. Milled log houses are designed with a tongue and groove system (or cope system) that utilizes interior gasket material to seal the space between logs. This design can require a thin ½ to ¾ inch added chinking to seal any gaps.


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Applying the Chinking

If you are planning on chinking a house that already has chinking, do not place the new over the old. The old must be removed before applying a new chinking. A clean surface allows for optimal adhesion of the new chinking. In all designs, gaps require a backing of some type to apply Perma-Chink over. For reclaimed logs or logs with an irregular chink joint, scribed foam bead board is used for backing – Perma-Chink is then applied over the backing. In other applications, beaded foam insulation or specifically designed backer rods are placed in the gap before a 3/8-inch layer of Perma-Chink is applied over the backing.

Chinking material is troweled smooth and pressed tightly to the upper and lower logs. The goal is to have a consistent layer of chinking, then the required layer of Perma-Chink is applied over the backing. The white backing material is applied first, then the Perma-Chink is applied over the backing at a depth of 3/8” thickness. The applied chinking is then troweled to achieve a smooth surface, paying particular attention to pushing it tight against the upper and lower logs. The goal is to have a consistent layer of chinking that, when cured, is a minimum of 1/4 inch thick.

We’ll travel anywhere in the U.S.
to do chinking.

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