fixing shed roof

andrewf75

Hi all,

My flat (slight slope) felted shed roof is leaking. Some of the timber seems to be sagging so I guess this needs to be replaced first, its only one or two planks. Question is should I re-felt it or would coroline sheets last longer? Can they be used on only a slight slope?

Cheers!

Head_The_Ball

I know nothing about Coroline.

Have you considered EPDM?

I used it to replace a rotting felt roof.

It is about three times the price of felt but it lasts more or less for ever.

Have a look at that and compare it to Coroline.

andrewf75

Thanks, yes that could be an option. I have an extension with it on the roof so I know the stuff.

savemoney

Coroline is a begger to cut but can be done if done slowly and with some support. Have you thought of using Cromapol excellent product for repairing leaks, I even use it for various other solutions like preventing rotting on the allotment on gravel boards. You probably need to fix the sagging though. You can get 5Kg tin for around £26-£27 on ebay.

I use Coroline on my lean too attached to shed at allotment for a greenhouse. The shed roof I replaced with EPDM but had I known how good Cromapol was I would have used it on felt roof

andrewf75

Thanks, sounds like EPDM is the way to go. The cromapol sounds good, but would clearly only be a temporary repair
Looks like a piece of EPDM will be around 50 quid

datostar

I've seen marine ply nailed over an old saggy felted roof to provide a good base for EPDM. Sorts out unevenness and sagging too. Any damp will dry out from the inside in time.

seatbeltnoob

I would highly recommend EPDM. I have it on my hand built shed. I chose a very gentle pitch so that I can maximise the interior volume. Had pent sheds in the past where the height on the sides were very low. People go for pent sheds because they look good. But an apex with the minimal-est pitch is ideal. I went for 1:6, but if I were to do it again I would have gone for 1:20 - just enough for rain to run down.


I got EPDM for very very cheap from gumtree. Excess from someone elses job. It is quite expensive to buy brand new.

andrewf75

datostar wrote: »

I've seen marine ply nailed over an old saggy felted roof to provide a good base for EPDM. Sorts out unevenness and sagging too. Any damp will dry out from the inside in time.

does it need a plywood base? or can I glue it to the existing roof battens (after replacing the rotten ones)?

datostar

andrewf75 wrote: »

does it need a plywood base? or can I glue it to the existing roof battens (after replacing the rotten ones)?

A plywood base would be the ideal, but given EPDM's longevity and intrinsic waterproof nature you should be able to get away with the cheaper chipboard type boards instead. I'm visualising your roof battens as something like a house loft without flooring, i.e. sticking up at intervals. I think you'd be better with some kind of continuous surface for the EPDM.

EssexExile

I used 9mm OSB (sterling board) about 10 years ago & the roof is still as good as new.

andrewf75

datostar wrote: »

A plywood base would be the ideal, but given EPDM's longevity and intrinsic waterproof nature you should be able to get away with the cheaper chipboard type boards instead. I'm visualising your roof battens as something like a house loft without flooring, i.e. sticking up at intervals. I think you'd be better with some kind of continuous surface for the EPDM.

it is roughly 10cm wide boards fitted against each other - so separate pieces but it is a continous surface if you see what I mean! Maybe should have taken some pics first
Most of it is in good nick just need to replace one or two where the water has pooled and leaked in through the felt.