Sloping Ceiling Insulation

[thebadger7]

Hi folks

Looking for advice on best way of insulating a sloping ceiling (See pic). It's going to be my office so want it to be warm as possible.

It already has 35mm of woodfibre sarking board above rafters (with counter battens above for ventillation). I've got some sheepswool so I may as well use that under rafters.
Rafters only 75mm deep though. Thinking I should add some 25mm battens below rafters to get a bit more in. Could counter batten to get more depth. Final layer will be woodwool boards, and Cornerstone insulating render.

Does this sound sensible, so we'd have
- 35mm woodfibre
- 100mm sheepswool
- Cornerstone Insulating render (not sure on depth for ceiling part)

If I'm putting in battens under rafters, would it make sense to go perpendicular to add a bit of support, or just follow rafters?

Thanks!

Luke

 

[Stevers]

When I looked into insulating my man cave with a view it being a heated workshop if required, it was a real wake up call when I calculated how much heat would be lost and where, especially the aircrete 'insulating' blocks that I'd used not being that effective!
It would be worth looking at the R values and so heat loss through other elements of the space especially those large windows, but also the solid walls and door to the outside if there is one, before getting too carried away on the roof.