GRP vs EPDM (Fibreglass vs Rubber)

[guttermaster]

Hi,
Just thought ild advise you to go G.R.P all the way . As long as BBA approved resins are used then cracking will not appear.Also you can get 20 ltrs to cure in 5 mins if you wish , so it aint as risky as you think.I been installing G.R.P roofs for over 10 years. plz dont hesitate to email me for any advice.

G.R.P Roofs last forever!
west

hi i own a small roofing buisness in glasgow
and iam very interested in learning how to do g.r.p would you know of any
course or training schemes in the application. Also if you know any suppliers to the trade.

 

[corrie]

If you have very low pitch you can ballast over the EPDM with quartz to reflect heat. There is a geotextile membrane goes between quartz and rubber to cushion. You will be hard pushed to burst Butyl or epdm ......it`s amazing stuff! Guttermaster : open another thread and I will answer....... as it is a slight Hi-Jack.

Alex

 

[vinty]

Well during to inclement weather the roofs are still undone.

I still haven't seen any compelling argument against GRP, and during hot sunny days I'd much rather have a light grey shiny surface rather than a black matt surface. In the winter it doesn't matter ofcourse.

My cats could get really nasty if they found a soft surface where their claws adhere to, and EPDM might well be such a surface (can't say for sure though)
I also have three soil pipe supports that will need to be screwed into the new surface. The GRP would create a sealed surface around the screwholes, not sure how the rubber would be like.

GRP is a type of plastic, all plastics degrade eventually and become brittle also is your roof going to be insulated as there can be issues with condensation on grp roofs. EPDM is vapour permeable i.e. it can breath also 1 billion sq ms of epdm have been laid worldwide from alaska to saudia arabia, i have certificates of competence in both systems.

 

[Mikepeters]

Poly Your ears (polyurea) the next big thing in roof repairs,.

Single application can be done to 20mm thick, dries in about 6-10 seconds, and can be walked on after 20 seconds. no joints, no sealing sticks to anything. any colour, shiny or rough surface minimum 100 year lifespan..... you pays for it, but it will outlast the rest of the house.
One problem, I havn't got a clue who does it fr the public...... but I know a man that does.

 

[vinty]

Hi,
Just thought ild advise you to go G.R.P all the way . As long as BBA approved resins are used then cracking will not appear.Also you can get 20 ltrs to cure in 5 mins if you wish , so it aint as risky as you think.I been installing G.R.P roofs for over 10 years. plz dont hesitate to email me for any advice.

G.R.P Roofs last forever!
west

hi i own a small roofing buisness in glasgow
and iam very interested in learning how to do g.r.p would you know of any
course or training schemes in the application. Also if you know any suppliers to the trade.

Try Polyroof, I did a one day course with them, they train you and supply materials.

 

[SurreyRoofingEstimator]

Well during to inclement weather the roofs are still undone.

I still haven't seen any compelling argument against GRP, and during hot sunny days I'd much rather have a light grey shiny surface rather than a black matt surface. In the winter it doesn't matter ofcourse.

My cats could get really nasty if they found a soft surface where their claws adhere to, and EPDM might well be such a surface (can't say for sure though)
I also have three soil pipe supports that will need to be screwed into the new surface. The GRP would create a sealed surface around the screwholes, not sure how the rubber would be like.

Not all EPDM's are black, we install Rhepanol which is a fleece backed membrane and extremely strong, it is grey in color (as is GRP) and is very UV resistant, as far as your cable boxes go, we'd just cover it with the Rhepanol (or the non-fleeced component).

 

[donttellhimpyke]

GRP/Fibreglass roofs are more expensive, look brilliant when new [doesn't last], become brittle and crack with age [don't believe the guarantees...our local installer was uninterested when the roof failed well under 10 years...and he hosts a page on his website slagging off EPDM], cost a fortune to remove when they leak, can't be recycled and end up in landfill to the detriment of our little planet.
EPDM/Rubber don't look anything special when installed but last for far longer than GRP and look the same all the way through their life. It's the ONLY flat roof material recommended by Greenpeace and we replaced the GRP roof with EPDM 8 years ago [which was longer than the old roof lasted] and never had a problem since. IT ALSO COST A LOT LESS !!!!

 

[roofer1234]

not sure if you have had this work done yet but just thought i would put my opnion across to you just in case you haven't.

to be honest every roofing material manufacturer will design what they say are fantastic new products all the time and they all say they are better than the rest and the best thing to happen to flat roofing since the year dot. but the fact remains that the best and still widely used in the commerial and domestic market are two of the oldest, mastic asphalt roofing and built up felt roofing. and still with all these wonder products almost all of the maufacturers still produce these two older systems. and as a pro i would only ever tell someone to stick to what history has shown us and that is that asphalt and felt last as there is still roofs all over the country that have been waterproofed in these materials that still do not have leaks and have been completed for over 30 years. so if i was you i would stick with the proven and not with the paul daniels magic materials.

 

[foxhole]

Whats the concern with a black roof? , it radiates more heat in direct sunlight than any other colour to keep the roof cool.

 

[JohnD]

Whats the concern with a black roof? , it radiates more heat in direct sunlight than any other colour to keep the roof cool.

 

[foxhole]

 

[JohnD]

a black roof ABSORBS the most heat in sunlight.

The sun is very hot.

On a sunny day it will absorb far more than it radiates. It will not keep cool on a sunny day.

 

[manich45]

I am a Building Engineer and Project Manager.I have used both systems and can say they are both excellent products.

However for a new build extension or dormer I would probably opt for the GRP,simply because it just seems that bit more substantial.But for repair or replacement of existing roofs EDPM everytime, due to the speed of installation and the fact that it can be mechanically fixed over existing felt using the screw down strips, then adhering the membrane to this,or a 5mm exterior ply can be overlaid and the membrane full adhered to this.This saves time and money and is not as dependant on weather conditions as the GRP.The EDPM can accomodate movement in a poor deck where as the GRP can not.

Another concern with GRP is the amplified noise of rainfall due to its very hard surface.This is not a problem with a new build "warm Roof" or roof incorporating 100mm or so of insulation which minimises noise,but with a replacement dormer roof which may have little or no insulation you could be in for some sleepless nights.

With regards to cracking of GRP this is 100% down to installation error,ie to much movement in the roof deck due to light joists,excessive centres or thin roof sheets,or the joints not being bandaged and only usually occurs on larger expanses and not your usual domestic roof.A common proble seems to be when contractors have tried to save money by using softwood edge trims instead of the fibreglass ones reccomended.The softwood warps and the GRP cracks.However this should not happen if the timber is secureley screwed before laminating.
I am 16 stone and have often stood on finished GRP roofs to inspect them with no problems

The EDPM wont be damaged by birds (unless you have an eagle problem) and if pierced by a a falling slate etc can be repaired in 15 mins.The GRP is obvioulsy more impact resistant,but a little bit fusier to repair.

Both products offer simmilar guarantees both should last a lifetime,however the EDPM comes in slightly cheaper.
Horses for courses!

 

[Xenon]

In reality, GRP and EPDM are both cheap nasty systems.

Are they used on any scale in the Commercial Market? No.

Do they have BBA crtification for zero falls ? No

Are any offered with cast iron insurance backed guarantees ? No.

Are any inspected at installation stage by manufacturers tech dept? No.

EPDM is predominately used in small areas of the domestic market, mainly because it can be installed by anyone with half a clue, and is cheap to buy.

GRP is wrong in roofing apps due to its inability to cope with thermal expansion, it had a spurt in the 80's, and split after about 6 months pretty much everywhere. Its dire.

 

[manich45]

As both systems offer infinately longer lifespan and guarantees than felt,in what way are they cheap and nasty,and off interest what do you prefer instead?
The reason that are not as widely used as felt is due to a fear of the unknown by a lot of tradesman,I used to be one of them.
Cheers