In addition to their elegance and definitive look, full scribe (stacked) log walls can provide great thermal mass value and fire rating. However due to the natural properties of wood (slow evaporation of moisture from the wood cells), they are subject to a predictable amount of shrinkage in diameter or “settling” over time as each log in the wall slowly dries out and compresses from the weight above. Logs will not shrink much end-to-end, only in diameter. Typically log builders allow for 6% total shrinkage, or 3/4″ per foot of total wall height. This can vary slightly in different moisture index areas or with different species of wood, but can always easily add up to several inches of total shrinkage in a full-scribe log wall.
For example, a full-scribe log wall that is 9′ high may settle up to 4 to 6 inches over a period of several years, while vertical posts, conventionally framed walls, kitchen cabinets, or anything else structurally tied to the scribed walls will not want to shrink at all. If settling allowances are not properly planned for, resistances to the shrinkage can compromise the integrity of the home and lead to devastating consequences. Those who want the look of natural logs in their home without any settling should consider post and beam or timber frame construction instead, or one of the many hybrids such as fusion style, log décor , or even piece en piece .
No allowance for settling at the top of the post prohibits the top log from settling with the rest of the wall.
This is nothing to worry about, however, as all settling issues can easily be avoided by properly designing and communicating settling details to the log builder and contractor. Details should be looked at on a project-by-project basis, and can range from strategic placement of structural settling jacks on vertical posts, to specifying aesthetically pleasing decorative trim around frame walls, windows, and doors to cover up necessary settling spaces:
Typical settling detail for an interior post or wall underneath a log beam.
Once all applicable details are in place and properly constructed, all that’s left is minor maintenance and settling jack adjustments every few months to ensure the home is settling evenly throughout. Many log builders will be able to offer a maintenance plan to keep the home level until the log walls reach their equilibrium moisture content (EMC), which will vary based on the climate in which the home is built. This maintenance is necessary to maintain the value of the home as well as give log home owners peace of mind.
Cut-away view of a typical window settling detail.
If you would like any more information on log settling or the details we provide, please don’t hesitate to contact us !