A log cabin will settle down immediately after it is built – it doesn’t matter how hard you hit the logs as you are building it (for instance, one log may bow down a millimetre or two, but the next log on top may bow in the opposite direction – suddenly you cabin is 3 or 4mm higher). The weight of the roof bearing down on the cabin walls is enough to start straightening these “imperfections” out, but this take a little bit of time of course. It is easily possible for a cabin to settle down 50mm in the first few weeks – we have built very tall cabins that have settled 100mm! The taller the cabin, the more it will settle down (because it is made with more logs and therefore more joints between the logs which need to “mould” into each other). It is also a fact that the thicker the wall logs, the longer it will take to settle down (they are stronger and so will resist this compression phase for longer).
So that’s the initial settlement phase of a log cabin, but there is also the seasonal change as well…..
SUMMER – as the air temperature and moisture content decrease, this will be reflected in the wall logs. Depending on the exact use of the timber, it is classed as “normal” for external use at 19%. When timber loses moisture, it shrinks – in extreme cases, ie heatwaves, external timber can reach below 5% moisture content, meaning that a typical 135mm high log could reduce down to 132mm. This doesn’t sound like much, but if a cabin is 15 logs high, it means the cabin can be 45mm shorter than it’s equilibrium status (during Spring and Autumn)!
WINTER – conversely, timber swells when it gains moisture content (who remembers the old style wooden kitchen doors jamming up in the Winter???). This is where using a good quality timber treatment/paint comes in – it will stop too much rain getting to the timber face and stop too much being absorbed which would cause the logs to swell (and if left unprotected long term, going rotten of course). Nonetheless, the moisture content of the logs will rises during Winter, meaning the cabin could be as much as 20mm taller than it’s yearly average.
So that is the background to this article – log cabins move up and down!
This then leads on to a helpful hint when painting cabins (usually in the first few days after installation and before any of the settlement / movement has happened) – Most people would paint around the window and door trims / architraves……But what happens when the cabin walls move?…….
Winter – the walls swell up, leaving potentially unpainted wood showing above the frame.
Summer – the walls shrink, leaving unpainted areas below the architrave “haunches”.
There is of course a very simple solution that most people don’t think of – unscrew the top trim from the frame before painting, and then replace when the cabin is painted, it’s as simple as that! It doesn’t matter what time of year it is (ie the timber moisture content, and so the height of the cabin) – the cabin will still move up and down (as it should do) but there won’t be any unpainted timber showing.
The more all-encompassing way to paint a cabin is to paint it before the windows and doors have been fitted – which means that all of the logs are covered all round, even the parts that can never be seen. Ensuring a longer cabin lifespan.
The best option is one that not many other companies offer (but we do!) – factory painting. Not only are all logs (including the tongues, grooves and all notches), windows, doors, fascia boards painted all round (twice) but you get a much better finish because the paint (or stain) is sprayed on, so there are no brush marks at all.