Pressure treated shed

[ivanmacx]

We have just had a shed installed in our garden. I asked in advance whether the shed would be pressure treated and they told me it would. Now it's installed, there is no sign of any pressure treatment. It is made of tongue and groove cladding which is a normal timber colour on the inside and there are no stamps or markings on any of the timber. The outside has a green preservative stain, but it's clear that's been painted on.

The shed company tell me that the timber is pressure treated with a clear preservative, and they added a coat of preservative on the outside for extra protection. They say it is treated to EN 335 3.1 standard. They say that the cladding is marked on the ends of the boards so as not to deface the visible sides. They say the studwork is not pressure treated (which is fine).

I know this is possible, that pressure treatment can use a clear preservative these days. However, there are no markings on any of the board ends. It's possible that every exposed end is a cut end, but it seems like a big coincidence.

Two questions. Can anyone suggest a way that I can satisfy myself that the timber is actually pressure treated? Should I be able to see evidence of the clear preservative on the board ends? Is there any way to test it?

Secondly, is it normal for a shed to be treated to EN 335 3.1, which is for coated exterior timber. I would have expected 3.2, uncoated, because normally sheds are not painted. I think with 3.1 it means we have to re-proof it once a year, which is not what we wanted.

Any advice anyone can give would be very much appreciated.

 

[Notch7]

It seems there is only subtle difference between 3.1 and 3.2

There are two sub-classes in this use class:
• Use class 3.1 (UC 3.1) – where the wood or wood
based product will not remain wet for long periods;
water will not accumulate;
• Use class 3.2 (UC 3.2) – where the wood or wood
based product will remain wet for long periods
and water may accumulate.
In this environment the moisture content of solid wood
can be expected to be frequently above 20%, and thus it
will often be liable to attack by wood-destroying fungi.
Examples include external joinery, decking boards and
joists, cladding and fencing rails;

It mentions cladding under the 3.2 spec but cladding isnt likely to rrmain wet for long periods unlike deck boards.

I dont know how timber can be tested to see if its been treated or not

 

[ivanmacx]

Thanks. That's helpful. On the one hand I'm reassured because water is not likely to accumulate. On the other hand it seems that 3.2 is the recommended standard for cladding and there must be a reason for that.

Anyone else have any insight?