Chinking is the mortar-like material between the horizontal joints of log homes. Chinking enhances a log home’s appearance and creates a weatherproof structure, preventing air, moisture and insects from infiltrating into the home. Chinking also adds insulation. Basic homemade chinking is cost effective and offers the same if not better stability and durability as commercial chinking materials.
Logs separate from their chinking or caulking, for a variety of reasons, including log shrinkage (and the expansion of the wood during wet periods), differential movement resulting from uneven snow loading and the freezing of moisture that has penetrated the existing chinking.
When properly applied, chinking drastically improves a home’s energy efficiency by reducing heat loss where the logs meet. In fact, chinking can boost the R-value (a measure of heat transfer) of a chink joint to almost the R-value at the log’s center.
Natural Log Cabin Chinking Recipe
There are many commercial chinking materials available, most of which use a variety of chemicals and sometimes concrete. The recipe below is a time proven classic natural recipe, is cheap to make and friendly to the planet.
2 parts clay (a clay rich soil with over 30% clay will suffice)
1 part sifted wood ashes
1/2 part salt
Add water to mix to desired consitency
How to make Chinking
Prepare a chinking mixture and combine ingredients in a bucket or tub. Add enough moisture to make a heavy paste that will form a ball when squeezed. Chipped straw, moss or sawdust are sometimes added to do-it-yourself chinking recipes.
Log chinking is also a design element of your home, often contrasting with the color of the logs. To color chinking material, use a different colored clay or natural color pigments available from home building supply or arts and crafts stores. Follow package direction to achieve the desired density of color. (Keep a record of how much pigments you added to be able to duplicate the color.)
How to Chink
First remove any loose and cracked old mortar. Fill open cracks and crevices in the logs by stuffing them with torn strips of rags, dried forest moss, small stones or small pieces of wood. You can use lengths of rope, or straw, even dried grass(hay) has been used traditionally. You use anything that will fill up the volume of a split or crack in a log. Choose materials to fit the gaps. Push the filler material into the gap with a screwdriver or putty knife. You will cover the filler material with chinking, so don’t worry about appearances.
Scoop out some chinking from the bucket into a small container and use a metal or plastic spatula to apply. Press the chinking well into the seams to insure proper bonding. Chinking needs to be applied about 1/4 to 1/2 inch (6 to 12mm) thick. Too thin and there is not enough to adhere properly to the logs and you may see tears or rips in the chinking, too thick and the chinking is wasted and will take too long to cure. Cleanup any spills from your logs with a little soap and water immediately to prevent staining your logs. You can keep your unused chinking in airtight containers if you protect the chinking from freezing.