Exterior grade chipboard?

[colin]

I've just had a flat roof on an outbuilding extended and re-felted and can see that part of the fascia (?) has been constructed using chipboard. The chipboard goes under the felt and then extends downwards by around 8 inches to the gutter with this bottom section being exposed to the elements. I've know idea if the chipboard is an exterior grade or not.

Chipboard itself isn't an issue since the section is out of sight at the rear of the outbuilding, however I did wonder whether chipboard (even if it is an external grade) is a suitable material for something that is constantly and directly exposed to the weather?

Thanks!

Colin

[John]

Will not make any difference in your situation

Could be the answer as to why it's done in chipboard!

No it is not suitable, unless totally covered in a waterproof barrier, i.e. felt and bitumin etc. The exposed chipboard will expand in the first rainfall and fall to pieces before Xmas. Speak to the builders/roofers and get it done properly.

HTH

John

[colin]

Many thanks John. I've contacted the roofer and its apparently OSB (Stirling) board rather than chipboard. Said roofer suggests that this is OK once painted?

Colin

[George]

Did you tell him you cant get behind it to paint it? lol This will rot in time.

[TMC]

Sterling board is used by every glazing co to board up broken windows and windows on empty buildings to prevent them being broken.

It looks pretty tacky once it gets old but does not fall to bits in the wet

Tony

Would last at least as well as softwood & paints up ok