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Why Your Log Home is Moving (And How to Manage Shrinkage)
If you are a new log home owner, you might hear your house "groan" at night. You might notice a door sticking that used to close perfectly. You might see a new crack (check) appear in a wall log.
Don't panic. Your house isn't falling down. It's just getting comfortable.
Log homes are dynamic structures. Unlike a stick-built home which is static, a log home is constantly interacting with its environment. As the massive timbers dry out and acclimate to your local humidity, they shrink. This process is called "Settling."
Here is the science behind why it happens, and the protocol to manage it without stress.
The Science: Radial vs. Longitudinal Shrinkage
Wood is like a bundle of straws.
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Longitudinal (Length): Wood does not shrink much along its length. A 10-foot log will stay 10 feet long.
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Radial (Diameter): Wood shrinks significantly in thickness. As moisture leaves the cells, the log gets thinner.
The Math of Settling:
Since your walls are stacked horizontally, every millimeter of radial shrinkage adds up.
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The Reality: A standard 9-foot log wall can lose between 1 to 4 inches of height in the first 3 years, depending on whether the logs were "green" or kiln-dried.
The "Equilibrium" Goal
Your logs will continue to shrink until they reach Equilibrium Moisture Content (EMC). This is the point where the moisture in the wood matches the humidity of your climate.
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In humid Florida, logs settle less.
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In arid Arizona, logs settle more.
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Note: Central heating acts like a kiln. The first winter you run your furnace is when you will see the most movement.
The Preventative Design Checklist
If you are still in the building phase, ensuring your builder installs these features will save you headaches later. If you are already living in the home, check that these are functioning correctly.
The Sealant Strategy (Elasticity is King)
This is where Weatherall comes in.
As logs shrink, the gaps between them change shape. A rigid mortar or cheap caulk will snap under this pressure, creating air leaks.
You need a sealant that acts like a rubber band.
1. The Gaps Between Logs
Use Triple Stretch Chinking. This product is engineered for Hyper-Elasticity.
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How it works: It creates a strong chemical bond to the wood fibers. As the log shrinks away, Triple Stretch elongates to bridge the gap without tearing.
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The Fix: Inspect your chinking every Fall during the first 3 years. If you see separation due to extreme settling, simply cut out the bad section and apply a fresh bead.
2. The "Checks" (Cracks in the Log)
As logs dry, the tension causes them to crack. This is normal.
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Hairline Checks: Ignore them. They are cosmetic.
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Up-Facing Checks: If a crack on the top of a log is wider than 1/4 inch, it can catch rain. Insert a Backer Rod and seal it with Textured Caulk. This keeps water out while allowing the log to continue moving.
3 Rules for the "Settling Years"
1. Don't Fasten Rigid Items to Walls
Avoid attaching tall rigid items (like tall bookcases or shower glass) directly to a log wall without a slip bracket. If the wall shrinks 2 inches, the item will bow or break.
2. Monitor the Roof Valley
If your home has complex rooflines, settling can cause "valleys" (where two roofs meet) to shift. Keep an eye on flashing to ensure it stays watertight.
3. Be Patient
Settling is most aggressive in the first 2-3 years. After that, the movement slows down significantly. However, because wood absorbs humidity, your home will always "breathe" slightly with the seasons. This is why you always need flexible chinking, not rigid mortar.
Frequently Asked Questions
Will my kiln-dried logs still shrink?
Yes. Kiln-drying removes most of the water, but not all of it. Even a kiln-dried home can settle 1-2 inches as it acclimates to your specific climate.
Is a "check" (crack) a structural defect?
Almost never. Checks are a natural release of tension as wood dries. Unless the crack goes all the way through the log (which is rare), it is purely cosmetic. Just seal the up-facing ones to keep water out.
Your home is alive.
Don't fight the movement; manage it. With the right structural adjustments and elastic sealants, your log home will settle into a tight, energy-efficient fortress.
