Underboarding our Winter Garden Roof

[ToughButterCup]

Part of our roof is outside the heated envelope: open to the fresh air in other words. Have a look at this image. The Durisol wraps the heated envelope: the steels the Winter Garden.

 

 

Here's a different route view of the same thing.

 

The area on the left is the winter garden. And while there is a window on the plan, we are now not going to have that window: just a plain roof. (Too much solar gain and too much of a Right Royal pain in the Botticelli.) The strange hatching on the roof indicates  solar PV -being fitted tomorrow. Woohoo Hoo.

 

Now that we have decided to fit tiles the left hand area of the roof, it occurs to me that the underneath of the tiles will need to be boarded. otherwise the tiles will just be blown off their battens because the wind catches that corner of the house quite a lot.

 

Question. What with? OSB3? Marine ply? WBP? Plasterboard, Caba Board?

 

Any ideas ?

 

 

[PeterW]

I'd use Cement board or something similar

[Ferdinand]

May be an obvious question, but why not enlarge the solar array?

[Russell griffiths]

I’d have a look at the new exterior grade boards by a company called medite smartply. 

[ToughButterCup]

14 minutes ago, Ferdinand said:

[...] why not enlarge the solar array?

 

because that would suffer from the same problem: being lifted UP by the hooley caused by the Wind Trap underneath it . That's what I have renamed the Winter Garden - time spent standing talking to people in the Winter Garden area - I've noticed it's a bit more drafty there than elsewhere.

[Mr Punter]

Magnesium oxide board (MGO board) might be good.  It will stiffen up the roof a fair bit too.  Water and fire proof.

[ToughButterCup]

Will 9mm / 11mm do do you think? Rafters are at 400 centers....

I'm thinking OSB3 would do as well

[Mr Punter]

11mm feels much stiffer and the price difference is v. small.  If you OSB it may be prone to mould.  Some of the MGO can be left without even painting the underside.