Why Most Treatments Don’t Work on Log Cabins!
We get over 5,000 visitors a year to our Log Cabin Problem blog page and in 2023, after the hottest summer on record, the number of visitors to this page exceeded a staggering 7,000.
Why are so many people having issues with their log cabin? It’s down to three combining factors. Some of the most diverse weather patterns in the Northern hemisphere, extreme highs and lows of atmospheric humidity, and the wrong type of log cabin treatment used. When I say the wrong type, I’m referring to log cabin treatments labelled as microporous.
Throughout the UK we’re subjected to extreme weather conditions on an almost daily basis. The phrase ‘four seasons in one day’ could easily describe a typical day’s weather pattern, throughout any of the seasons. Frost, rain, sunshine, wind, rain, more rain, some sunshine thrown in now and again, more rain, hailstorms. Sound familiar? All of these are constantly chipping away at our log cabins, trying to damage the surface cells of the timber, and expose any weak points to gain entry to our cabin. None more so than the end grain which behaves like millions of drinking straws readily transferring water and moisture inside the cabin.
As the air cools the moisture level in the atmosphere increases and when the air gets warmer the atmospheric moisture level decreases. This is perhaps one of the most important points to remember when dealing with timber because the moisture level inside all timber wants to be the same as the moisture level in the atmosphere. This is technically known as the moisture equilibrium content of timber. When the atmospheric moisture level increases so does the moisture level in timber resulting in the cell walls of the timber increasing in size, which in turn causes the timber to expand. The opposite is true when the atmospheric moisture level decreases, so does the moisture in the cell walls of timber, causing it to contract.
Putting this into context, during the winter and early spring of 2022 a 100mm wide piece of timber would have had a moisture content of 30%. In August 2022 moisture levels had fallen so much that the moisture content of that same piece of timber would have dropped to 6%. Timber decreases in size by 1mm for ever 4% decrease in its humidity level. That’s a contraction in size of 6mm. This might not sound very much but a log cabin wall consisting of 20 logs at 100mm per log will decrease in size by a staggering 120mm or 12cm.
In order to prevent the timber from losing, or gaining too much over a short period of time requires the application of a suitable treatment to stabilise this moisture content equilibrium, and this is where the problem lies. Virtually all exterior wood treatments are generic and not specifically made for the high demands of a log cabin with its ‘free floating’ wall design. The logs of a log cabin aren’t nailed to a timber framework like a shed, so have full freedom of movement which leads to several movement related complaints if the correct treatment isn’t applied.
Most modern treatments contain just one weatherproofing ingredient which is usually some type of resin or silicone. Whilst resin and silicone are both waterproof, they’re not moisture proof. You’ll see many resin and silicone orientated treatments described as microporous or breathable. This means the treatment allows moisture to pass freely through it and given how moisture affects the movement of timber, that’s a recipe for disaster! Micro porosity doesn’t benefit the timber. Timber doesn’t need to ‘breathe’. This micro porosity is designed to prevent these resin and silicone only treatments from blistering when moisture gets trapped behind them. The only benefit microporous treatment has is when it’s applied to the cladding of a house allowing steam from showers and cooking vessels to escape during the winter, when the windows and doors are kept closed.
Secondly, resin and silicone cure hard and due to their porosity allow the timber to expand and contract. This movement causes micro tears in the resin and silicone allowing more moisture to enter the timber, increasing the movement and increasing the micro tears. This causes an increase in movement related issues and as the micro tears become wider and more numerous, water ingress will follow.
Thirdly, resin only treatments don’t prevent rainwater from entering the end grain of timber, and this is the primary cause of leaking in the corner of a log cabin. Resin dries hard, a process known as curing. The resin is absorbed into the end grain and cures. Due to its porous nature the timber can still expand and when it does a gap is formed between the hard resin and the cell wall of the end grain. Rainwater is absorbed into the end grain and freely passed through this gap, leaking into the log cabin’s interior.
If you’re interested in learning more about moisture and its effects on timber take a look at our blog post on wood and moisture
Now that we’ve explored the reasons why a log cabin needs a high-performance treatment to stabilise timber movement, and why almost all exterior wood treatments are unsuitable log cabin treatments, let’s take a look at why Timmersol’s Log cabin & Decking Treatment does stabilise the movement of timber.
Why Timmersol Log Cabin & Decking Treatment Should be Your First Choice
As mentioned above virtually all exterior wood treatments contain only one weatherproofing ingredient which is usually some form of resin. Timmersol Log Cabin & Decking Treatment contains three powerful moisture limiting ingredients; Linseed oil, wax, and a blend of resins which form better resistance to weathering than one stand alone resin and are prevented from micro tearing because the wax and oil stabilise timber movement. These ingredients are encapsulated in a solvent liquid carrier, allowing each coat to meld with the previous coat, resulting in a very low build finish. The solvent breaks the oil and wax down to its lowest molecular form, which can then pass easily into the surface cells of the timber.
Once the wax and oil are embedded into the timber’s cells they avoid degradation from the sun’s harmful UV rays, providing moisture protection for up to five years before a maintenance coat is needed. Finally, the blend of resins provides a protective layer over the surface of the timber, locking in the added UV protectors, and any pigment in one of the coloured treatments. This gives Timmersol Log Cabin & Decking Treatment it’s unique nano porous, triple barrier system.
As already mentioned, the solvent in additional coats will reactivate the ingredients of previous coats allowing the wax and oil to further penetrate the cells of the timber. The more coats applied the deeper these ingredients penetrate the cells of the timber. Three coats are the recommended quantity for full penetration of the timber’s surface cells.
Better Protection Equals Less Waste
It stands to reason that a well-protected product will last a lot longer than a poorly protected one. It’s a terrible waste to see an exterior timber product dilapidated and rotting when, with the right care and attention, it could have lasted a lifetime. Wood is such a versatile and beautiful product, and to some extent, softwood is renewable but as the demand for timber increases, so does the speed at which the tree is grown and harvested. This dramatically reduces the quality of the timber, producing timber that is knotty and has more faults than slower grown timber. The result – more waste at the sawmill.