EDPM or Torch on Flat

[Jeffb]

Hi what would recommend, I have a 8.6x6.3 flat roof fall 6.3m direction. Having spoken to various installers and suppliers most professionals are recommending Torch on felt as the best product. They say EDPM can become unstuck delaminate wrinkle etc due to expansion and contraction it’s more of a diy product? 
Does anyone have any experience of these problems with EDPM . I was considering the Thicker Firestone product . 
any thoughts or experiences much appreciated.

thanks Jeff 

[Russdl]

I can’t speak for the longevity of EPDM but I can vouch for its DIY-ability, recently did our garage roof 7m x 7m at the front and 5m wide at the back. Apart from getting the EPDM up on the roof, it was heavy, the rest was child’s play. 
 

The supplier of my EPDM recommended it was laid on OSB and not plywood, telling me that plywood delamination could be an issue, so ours is stuck on OSB. Maybe that’s the delamination issue you’re being told about?

 

I’m sure someone on here has longer exposure to EPDM to inform further. 

[elite]

Felt is cheaper, but has a shorter life expectancy.

 

I would be considering EPDM or GRP - I have EPDM on the renovation extention (replaced leaky felt roof) and on the garden room.

 

5 years on with the garden room and no delamination or wrinkles, only two years on the renovation but no issues when I was up there a couple of months ago. Garden room was onto OSB (cheaper than ply), Renovation was onto existing deck (ply).

 

The nice thing about rubber is that there are no joins (assuming a simple roof and you can get it big enough), and it can expand and contract

[Alan Ambrose]

I like epdm a lot after using it on my shed roof. I think sticking it down is a bit of an art (like getting sticky back plastic down without any air bubbles) and I wasn’t that convinced by the glue that came from the same supplier - it looked suspiciously like PVA. The odd air bubble isn’t going to make any difference to the watertightness.

 

My bit was 6x4m - so half the size. We could manage fairly easily with two guys. You might want more bodies (a) to get it up there and (b) to manhandle it into the right spot / orientation.

Edited July 12 by Alan Ambrose

[Marvin]

Hi @Jeffb

 

All good info above. I choose EDPM every time, however the neighbours GRP is also a good product (But I have never installed GRP)

 

I used EDPM. 5m by 12m. on OSB.

 

Put it on myself. One piece plus bits, and the PVA type glue.  Fixed a few of these over the years. Definitely excellent for sheds but you have to use the contact adhesive on pitched roofs and vertical surfaces.

 

I have used https://www.rubba-seal.co.uk/ for all my EDPM. There are others.

 

Good luck

 

Marvin

 

 

[Jeffb]

Thanks for the replies , has anyone got an EDPM roof that’s over 10years old ? 
 

[Onoff]

How about Desmopol?

 

I love the idea you can periodically just paint more on. 

[Alan Ambrose]

@Marvin Put it on myself. 5m by 12m.

 

Bloody hell - how did you do that? Impressed. 135kg by my reckoning.

[Tetrarch]

On 11/07/2024 at 23:14, Jeffb said:

Hi what would recommend, I have a 8.6x6.3 flat roof fall 6.3m direction. Having spoken to various installers and suppliers most professionals are recommending Torch on felt as the best product. They say EDPM can become unstuck delaminate wrinkle etc due to expansion and contraction it’s more of a diy product? 
Does anyone have any experience of these problems with EDPM . I was considering the Thicker Firestone product . 
any thoughts or experiences much appreciated.

thanks Jeff 

 

I am a huge EPDM fanboy. I absolutely recognise your situation.  I installed my own EPDM loose lay rubber roof in my previous house in 2003 and sold it in 2021. It's still there and I never experienced a single issue. I have insisted on EPDM for our new extension and am delighted with it installed, but, my god, did I have problems finding an installer. Every installer wants to put in the thing that they do and finding a genuine EPDM specialist is very difficult.

 

I don't want felt - it DOES crack eventually and it DOES leak eventually and it does need replacing. In my opinion it's a liability I don't need. 

 

I also hate GRP. I had a small GRP roof put over an external fireplace and it barely lasted two years before cracking and losing it's waterproofing abilities. 

 

I have no direct experience of the polymer paint stuff, a repair done with this in a commercial property that I help with has also failed, though this was 5 years after the repair

 

I used the thicker Firestone EPDM in my new extension and it is very much tougher than the normal stuff. I'm planning on a green roof at some point, so the thicker membrane seemed like the way to go.  Here's a pic of the finished EPDM

 

Good luck and regards

Tet

[Alan Ambrose]

>>> has anyone got an EDPM roof that’s over 10years old ? 

 

The general guarantee is 20 years if that helps. I've wondered whether the sun might eventually do mine in - it gets awful hot on there in summer. Mine's been there 5 years already and the last time I was up there it looked as good as new.

 

>>> I used the thicker Firestone EPDM

 

the 1.5mm stuff?

[Tetrarch]

7 minutes ago, Alan Ambrose said:

>>> has anyone got an EDPM roof that’s over 10years old ? 

 

The general guarantee is 20 years if that helps. I've wondered whether the sun might eventually do mine in - it gets awful hot on there in summer. Mine's been there 5 years already and the last time I was up there it looked as good as new.

 

>>> I used the thicker Firestone EPDM

 

the 1.5mm stuff?

 

Yessir

UV Study here from Australia (where they get quite a lot!) :

https://www.swiftsupplies.com.au/news-tips-and-guides/uv-resistant-rubber-guide/

 

Regards

 

Tet

[scottishjohn]

6 hours ago, Tetrarch said:

I also hate GRP. I had a small GRP roof put over an external fireplace and it barely lasted two years before cracking and losing it's waterproofing abilities. 

grp will out last any other choice 

if it failed it was simply badly laid  

main reason for grp not working is damp under it 

to do it right you must use new osb below it and don,t let it get wet bfore apllying grp matting and resin

 

[joe90]

7 hours ago, Tetrarch said:

I also hate GRP. I had a small GRP roof put over an external fireplace and it barely lasted two years before cracking and losing it's waterproofing abilities. 

Then that was not laid properly, I have fitted GRP roofing over many years and not one call back. If it’s good enough for boats, what's not to like 🤷‍♂️

[Marvin]

18 hours ago, Alan Ambrose said:

@Marvin Put it on myself. 5m by 12m.

 

Bloody hell - how did you do that? Impressed. 135kg by my reckoning.

Unrolled EDPM. Half up first, 2nd half up after. converted garage flat roof...

Edited July 13 by Marvin