What felt / membrane to use?

[sh4d0w]

I am pricing up to buy the gear to do my conny roof but the different types of felts and membranes avail is now a minefield.

Can anyone please give me some advice?

I am building a lean to roof to replace this one,
View attachment 92905

will be a timber and lightweight tile roof and maybe some Velux.

Thanks

 

[chappers]

are you sure the glazed frontage will be able to take the weight of what you are proposing.

 

[^woody^]

Yes that's a lot of weight for those flimsy frames

 

[sh4d0w]

I have got new frames and doors, the doors are being moved over, i have 4 steel posts in the frame spacers with a 100mm knockin between each frame for the steel. roof will be made of lightweight tiles @ 3.2KG per M2. Plenty strong enough

 

[^woody^]

An have you allowed for the bracing of the roof (ie it tries to push outwards) and wind and snow loading?

What tiles are 3.2kgs m2?

 

[chappers]

As long as your confident, in answer to your question, if your talking breathable membranes, then for a standard roof they're pretty much of a muchness,
But for membranes in general depends on how you plan to insulate your roof

 

[sh4d0w]

Thanks Chappers:
So from outside in;

Decra Lightweight tiles (3.2KG per m2)
38x50mm Laths
a form of breathable membrane - looking at https://www.roofingsuperstore.co.uk/product/uv15-breathable-pitched-roofing-felt.html
6x2 Rafters
100MM Celotex between
40 or 50MM Celotex fixed to the rafters in full sheets sealed with foil tape to form my VCL
12.5mm plasterboard
skim.

 

[chappers]

Sounds about right, do you really need 38mm battens, is that specified by Decra ?

 

[datarebal]

klober permo forte

 

[chappers]

That's my favourite too, especially if the roof is going to be left untiled or slated for a while, good tough stuff