Flat roof - felt or something else?

Mark M · 29 Jan 2020 at 15:33

I need to raise the flat roof over my utility room to insulate it, buidling inspector has cleared it based on the additional height which allows sufficient airflow apparently. What options do I have for the roof? I know there are newer types of roof or is felt still the option of choice?

Many thanks.

SeatIbiza · 29 Jan 2020 at 16:22

EDPM is the better stuff - it's rubberised. More pricey though but 20 year guarantees often...

Mark M · 30 Jan 2020 at 12:34

Thanks, the EPDM does look like the better solution and a few things Ive read about it suggests it stands up better to extreme weather conditions which could be good as its on the south side of the house so gets the sun virtually all day. Now to try and find a local fitter that knows what they are talking about...

hood1971 · 30 Jan 2020 at 13:07

Had EPDM put in a few years ago and been great. It is better value than felt as should last a lot longer.

hornetstinger · 30 Jan 2020 at 13:10

Whilst getting it done get it angled slightly to reduce standing water

xb8browney · 30 Jan 2020 at 13:17

We had EPDM done aswell, more expensive than felt but will last longer.

fastwunz · 30 Jan 2020 at 15:17

Hateful things flat roofs - I wouldn’t felt it - spend the cash and put EDPM on it

LACKERKNACKER · 30 Jan 2020 at 20:30

Any roof covering is only as good as the person installing it, EDPM is no exception. It’s good as it can be laid in one piece, but some installers struggle when the roof is nothing more than a flat slab, fitting around roof details can prove a challenge to some, I speak from the perspective of someone who had bad experiences with EDPM installers.

Our architect suggested a product called Sarnafil by a manufacturer called Sika. More expensive than EPDM but appears far more substantial than EPDM, good guarantee.

https://gbr.sarnafil.sika.com

As mentioned above, we had a real nightmare with our roof and EPDM, mainly due to the sub contractors used by our main contractor, but quality wise the sarnafil looks so much better, at one point we were considering a felt solution , which we could get a 20 yr insurance backed guarantee, but we couldn’t stop associating a shed roof and felt!

ANDARIAL · 31 Jan 2020 at 09:30

Fibreglas is another option
Not as good as EDPM (pretty close imho ) but lots better than Felt

Mark M · 31 Jan 2020 at 09:32

Looks like EPDM is the way to go. Its a fairly standard rectangular flat roof and assume there isnt anything too complex from an installation point of view.

Usher · 31 Jan 2020 at 09:44

We had one fitted on a flat roof using heavy duty Butyl Rubber in 1983, the same type that is used for lining man made lakes, the joins were vulcanised. It's still perfectly watertight and estimated to last for decades