Timber is a natural material and as such is not as stable as a man made structure – there are times when perfectly machined wall logs bend or twist after manufacture, usually as a result of changing moisture content within the timber itself.
Using these logs in the wall construction is not a problem, it just needs a little more care during construction. Wall thicknesses of 34mm and above will have sufficient weight to encourage the tongue and groove joint into the designed position without the requirement to use screws.
So what happens when the logs don’t behave themselves and additional forces are required to assist ?
In all but the very worst cases, using screws to fix the logs in place should be avoided. Using these fixings results in a permanent positioning, ah good, I hear you cry ! But what happens when the English sun makes a guest appearance and reduces the moisture content in the log and it shrinks. Worst case scenario is that the tongue and groove joint will open up – I have seen bad cases where you can actually see light between the logs – this is not good.
A method I use with regular success employs a soft faced mallet to apply appropriate hammer blows to the wall :
Once the wall is a third in total height tap the side of the wall with the hammer, in doing so it encourage the logs to settle in place. The weight of logs above will hold everything in place.
Work your way around the walls both inside and out, you’ll be surprised how successful this method is.
Carry out the same action when the wall is two thirs built and then on full completion.
A good way of telling how successful this has been is to look at the joints along their to make sure they are all even.
Take a look at the end of the logs where they join with their perpendicular neighbour. Are the tongue and groove joints looking snug ? If not, then using the soft faced mallet tap / hit as required to encourage the logs to locate more snugly.
Start at log number 2 at the bottom and work your way up the wall, you will be surprised how much space is created. Once you have completed one line of logs do the same on the ends at right angles, again starting at the bottom and working up.
Putting the above into action will ensure your walls are built well and without the need to screw together – your walls will be able to live and breath and give many years of good service !