MrMartin

I need some advice .... I have just had a new roof put on with slate tiles. It looks good, But..... I see that the tiling battens used are clear in colour, i.e.natural wood colour, yet all the other tiling battens used in other roofs in my village are either blue or green ish in colour. I take the colouration to mean that they have been treated with a wood preservative. Whilst the battens used by my contractor are stamped with BS5534 I suspect that they have not been treated with any wood preservative. Looking on the NHBC Standards website it is not clear to me whether treating treating battens with a preservative is mandatory or a recommended code of practice. Furthermore the building specification written by my surveyor, it states that the battens must be to BS5534 and treated. Can anybody cast some professional opinions on this please? Thanks