Treatment of a Log Cabin – Customer Questions

I always try to offer the best advice I can and sometimes, although I recommend our Timber Treatments I do also recommend others to give customers a choice for the treatment for their log cabin.

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Customer Email

A customer wrote to me following our email exchange:

“I really appreciate the extra detail as I certainly want to get things right – it’s very good of you to pass on your experience. I have tried to research this online but it’s surprisingly difficult to find good simple advice for a complete novice. A step by step guide “painting a shed for dummies” would probably clock up a lot of hits on your site! 😉

I have enough information to make my own decisions now and understand how important the base\DPM and ventilation are.”

My Response and Advice

I’m not going to write such a blog post as suggested for ‘dummies’. However, it might be useful for you if I copy my email to Mr M that prompted this reply. It does go on a bit but may help with further treatment questions and your understanding of it.

“I tend to advise the simplest option – three coats of something expensive. Don’t use ………. on it’s own, especially their shed treatment as it’s terrible for log cabins.

For the first few years of life of a log cabin, overkill is a good thing. The wood is kiln dried and I have a personal theory on this. It is because the straws that make up wood are still very open. The wood is not really dead as dead should be. It’s an artificial death that we’ve forced on the poor tree.

It’s this openness that absorbs and expels moisture from the air so quickly. Wood is basically made up of loads of straws (needed to suck up moisture from the ground) and it’s these straws we want to bung up. A good few coats of a good treatment does this and there’s never a problem.

Ideally timber should be air dried. Though if we did that, you would wait years for your log cabin / table / worktop / kitchen etc and no one wants that.

A cheap treatment won’t stop the transfer of this moisture. There isn’t enough thickness to it to stop the moisture flow. If you use something cheap she will expand and contract a lot in the first year.

Second and third year you will not see it as much, this is because I think the straws have collapsed slightly and / or bunged up. The wood is also more dead and starts to behave more like air dried timber with less movement.

Preserver is not necessary when a building is well ventilated. If a building is not treated at all but is still ventilated it will not come to harm either please see this old girl who has never been treated: https://www.tuin.co.uk/blog/maintenance/log-cabin-treatment-panic/ (some expected patterns of behaviour though)

Timber treatment and what is recommended by me, the producer, the treatment supplier all have different reasons.

From my point of view, I don’t want concerns after one year that the building has expanded / contracted and there are gaps or white bits showing. This is what wood does. It expands and contracts and if a customer understands this it is never a problem. Gaps only appear if restricted by a window or door frame holding it in place. Your cabin will move quite a bit over the first twelve months.

Sometimes though we see something different. This year we had a problem with one of our show buildings. When the Spring hit, one side contracted quicker than the other. This was due to only one coat of treatment being applied and the sun beaming very strongly on just one side, the other was in total shade. Moisture expels quicker on the shaded side when this happens. I knew what the problem was and sure enough, a week or two later, everything was equal and applied another coat. No more problems!

This is why we say 80 – 120 microns depth of coverage. It is what all the good and expensive treatments will give you. They all say 2 – 3 coats to make sure the depth is thick enough. This closes the straws, stopping uneven movements.”

I have since written a separate article about the depth of treatment and moisture content in wood worth reading.

“Next, we can move onto the producer. Both he and I know for certain that wood will never rot if allowed to ventilate. We do however have to account for the following:

• A dodgy base
• Water sitting at the base
• Foliage up against it
• Insects eating the wood
• Bird droppings, introducing fungi
• No damp proof membrane
• Etc.

This is why we will want a preservative. It stops and inhibits anything forming should one be a bit forgetful and not realise this. This stops a call in 5 years time.

Then we come to the paint / treatment manufacturer – They will be wanting to cover their butt. They will want overkill, belt and braces and will ask you for everything, the same as we should do. If anything happens they will want to ensure you did everything correctly. They also know that wood doesn’t rot if ventilated but also want to watch for the errant customer. When done correctly, no matter what you do to timber, it will always be fine. But, in poor ventilation and lots of moisture, treat more regularly.

If all of the above is understood, and the inherent nature of wood is understood such as expansion, contraction, cracking, splitting etc: https://www.tuin.co.uk/blog/common-problems/cracking-and-splitting-in-timber/ then a good quality treatment is enough, two to three coats applied the building will look good for several years before re-application (mine was using S—— years ago, all I do is pressure wash it yearly, it could do with a touch up but it’s still rot free) If though it is wet constantly then more considerations need to be made to guard against rot caused by damp or infestation.

My advice is good ventilation, a good base and a DPM is the most important thing to give a log cabin a good start in life.

From then on a good treatment of about 2 – 3 coats. Ideally something that does it all without under preservatives for ease. Something that looks good and you don’t have to re-do for a couple of years. (our treatments are very good by the way!) Remember what wood does naturally and enjoy it. Bear in mind though as well, one of the reasons why we buy a good treatment for a log cabin is the elasticity, the bloomin’ things move and this elasticity does help a lot especially in the joints over the first year and is very important, cheap treatments will not give you this.

I hope this has helped?”

Treatment Confusion

Not long after this discussion, I received an interesting question – “Why don’t you treat a log cabin before delivery as standard like they do with a shed?”

I’ve answered most questions I think in this blog. But yes, I haven’t yet answered this one.

The simple answer is ‘cos they’re tricky blighters and are not a shed.

A shed is easy, first we make a frame on a bench, pop some cladding on it 12mm thick, nail it on with a nail gun to create a panel. With all the nails in it it’s not going to go anywhere. We can then chuck it in a dip tank for a few minutes or if we’re a posh factory a spray booth and we’ve got a treated shed. Easy! We know as well that nothing is going to happen to it as it’s all really well held together.

A log cabin is slightly more tricky. It doesn’t have a frame, every single log interlocks into each other and we want those connections to be tight and remain tight over the years (Corner connections in log cabins). To do this we kiln dry the timber to a moisture content level commensurate with the country the cabin will be in, generally to around 14% for the UK. We then mill the logs in highly accurate computer controlled machines and out pops a log cabin.

If we then muck about with it the logs can all absorb moisture at different levels. This affects the milling and, subsequently, the installation as construction is so precise. Plus, you spend a lot of money on us providing you beautiful Spruce (Types of timber in log cabins) do you really want someone else to muck about with this? Isn’t it better to treat it how you want to?

We do though offer some treatment options:

• Tanalisation of log cabins

You will notice how long the lead time is, this is because we want to make sure everything dries properly and remains stable for an easy install.

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Please also see another post: Log Cabin Treatment Gone Wrong

More … I’ve recently been asked about our treatments:  This post relates entirely to the Tuin range of Log Cabin Treatments and clarifies what and how we recommend they are used if you choose to use our range.