flat roof advice

[nearthemark]

Hi,

I'm building a summerhouse, the roof will be 12x16ft with a slope of 2 degrees (1 in 30), 18mm OSB.

Would be grateful for advice, cannot decide between felt, fibreglass, one of those products that you paint on, or a kit from Screwfix with a single membrane. The latter option seems most foolproof! I'm fairly competent diyer but never done a roof before.

Thanks,


Mark

 

[delmel]

Rubber is the way to go

 

[Notch7]

I agree, for for epdm.

avoid felt - felted flat roofs are for professionals only

GRP is messy and can be ruined if it’s a wet day

 

[Tetrarch]

Huge EPDM fan. Super easy to lay and lasts for decades

Regards

Tet

 

[geraldthehamster]

EPDM all the way

 

[nearthemark]

Thank you so much for the replies, I've found EPDM on eBay.

On another note, the roof will be 6 boards, so none will be completely enclosed, so I still need a 3mm gap between them or can they go against each other? I'd like them to be touching so there's not a gap for the rubber.

Thanks again for the advice,


Mark

 

[geraldthehamster]

You don't need a gap.

Have a look of the videos here, on how to do this

https://www.rubber4roofs.co.uk/epdm-training-centre/search

 

[nearthemark]

thank you

 

[Rod Simms]

The system is the least important aspect of any flat roof. Correct installation is most important. Most roof failures in the first few years are due to poor workmanship rather than material choice. As you are installing yourself I would go with a liquid system as these are easier to install and most have significantly more elasticity in them than GRP. If you install on a good day you should have no problems. Just prime the roof and follow the instructions. Liquid also makes complex details easier.

Best Wishes Rod

 

[oldbutnotdead]

If you've got a simple roof (no skylights, no chimneys, no odd little returns) then EPDM is the best way to go. GRP is very good for complex shapes but you can get into thermal noise and as said above, a rain shower at the wrong time can be very expensive.