Pressure Treated or Tanalised Log Cabin

Pressure Treated or Tanalised Log Cabin

The garden industry uses these two terms a lot. Similarly, timber often describes itself as ‘tanalised’ or ‘pressure treated’. Options are given with our log cabins for them to be tanalised, others give them options of pressure treatment.


The two terms used are describing exactly the same timber treatment:

  • Tanalised is actually a trademark, as is ‘Tanalith E’ which you will see sometimes. These brands have been around since the 1940’s.
  • Pressure treatment is the process carried out using ‘Tanalith E’ or similar.


The treatment process is carried out by placing the timber in a big tank. The door is shut and a vacuum is created inside it. Then the pressure treatment fluid is allowed to enter and is forced in the wood under the pressure. It penetrates to a depth of a few millimeters.

Pressure Treatment process using 'tanalith' or similar
Pressure Treatment process using ‘tanalith’ or similar


The main ingredient is copper with other chemicals added. Copper is excellent for protection against rot and insects. The other chemicals (Biocides) protect against other rot that the copper can’t such as ‘brown rot fungi’. These substances are not harmful at all and can be used around animals and children. Fish may be sensitive to it.

Rot Proofing of Timber 

It does exactly what it says and protects the timber from rot really well, internally they say about 60 years and externally about 30 years against any form of rot. It’s pretty good stuff!

Limitations with Log Cabins

For the treatment of rot there is no real limitations, it works and works really well. The main problem with pressure treatment of our log cabins is:

  • It is NOT a weatherproof treatment

You can of course not bother treating it, the cabin is not going to rot, well, not for thirty years or so but because it is not a weatherproof treatment you can expect the logs to absorb water which will result in rings and marks just like your coffee table at home with a hot mug of hot chocolate.

  •  It will discolour, it fades to a honey brown and eventually to a silvery grey.

Overtime it will discolour. We can pressure treat/tanalise your log cabin in green or brown but the same appearance will result. Normally over about five years.

Green Pressure Treatment

Green Pressure Treated Log Cabin
Green Pressure Treated Log Cabin featuring the Sten Log Cabin

Brown Tanalised Pressure Treatment

Brown pressure treated log cabin
Brown pressure treated log cabin Featuring the Halvar Log Cabin

There isn’t a great deal between them but both will end up looking the same in a few years.

  • All of the wood comes treated.

And this may be a problem for you. When the logs are put into the vacuum tank there is no way to cover one side, all of it gets treated so what you see on the outside is what you see on the inside.

Life Expectancy

You might be asking what the results are for all that extra effort…

In general, pressure-treated timber is designed to resist decay and insect damage, making it more durable than untreated wood. However, it’s not immune to eventual decay over time, especially in certain conditions.

As a good rule of thumb, this type of timber has a typical lifespan of 15-20 as opposed to the usual 10. However, regular treatment can prolong your cabin’s lifespan significantly. Read more in our Treatment Advice Blog.


If Holland read what I’m about to say I may well get ‘questioned’ on it, but, I really hate pressure treated log cabins. I try and steer my customers away from it.

In my mind as it’s not weather proofed you will still have to give your cabin a proper treatment, preferably with something expensive so you rarely have to repeat it. If you want it to stay looking good you have to treat it.

Most people love the bright airiness of the cabin, do you really want to be staring at green or brown walls and ceiling, we go out of our way to source white wood over red wood so you have exactly that, an almost white interior, to spoil it with tanalisation just isn’t on really.

However, with that being said, other customers I will positively encourage such as this one:

Tanalised Log Cabin Garage
Tanalised Log Cabin Garage

Now here is a prime example when tanalisation / pressure treatment is excellent, it has a damp car stuck in it, it’s open to the elements internally. Rot treatment makes sense! Here’s another one when I strongly recommend it:

Highly recommended to pressure treat this log cabin
Highly recommended to pressure treat this log cabin

Another prime example, I’d suggest to this customer to pressure treat the log cabin.  It’s constantly open to the elements internally and externally.  It makes sense.

All my other cabins, hmm, I don’t think it’s necessary, you’ve got to treat it anyway so why not put the money you would have spent on tanalisation into your treatment such as Sadolin, Sikkens or our excellent range of log cabin Paints and Log Cabin Stains designed for smooth planed pine wall logs.

Overall, I think it’s a bit like marmite, love it or hate it ….. up to you!

This entry was posted in Cabin Building Materials and tagged , , , , , by Richard. Bookmark the permalink.

About Richard

Meet Richard, a dedicated professional with a rich history at Tuin, contributing 25 years of experience within the garden timber industry. With an expertise in garden buildings. From design, manufacturing and installation for a range of timber buildings. Sheds to log cabins and all the way up to timber framed houses. In his time he had worked with experts all over europe, and also included his own personal experience of installing and testing Garden Buildings from a range of companies, models and sizes. You will find a majority of his blogs to include expert installation advice for your Log Cabin. Information on how timber reacts to different environments and the best way to preserve your garden buildings.

One thought on “Pressure Treated or Tanalised Log Cabin

  1. I would advise getting some sort of guarantee for the treatments as I have had ‘Pressure’ treated decking rot in under five years. NOT I HASEN TO ADD FROM THIS VERY REPUTABLE COMPANY.

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