So im getting ready to spend cash on the protective layer of my plat roof.

So, its about 30mtr2, 150 upstand in the middle for the roof lantern and it will have a build in trough running around two lengths so not completely flat.

The roof is south facing. 

I was looking originally at GRP but there may be issues of cracking with hot cold cycling.

EPDM but not sure if it the upstand and inbuild trough would be to fiddly.

PU? easy enough to paint on but not sure on toughness or guarantee.

Any tips, preferences or pit falls anyone?

 

Regards,

Warren.

GRP properly done will last 40 years.

We have just had our old corrugated asbestos roof repaired with a polyurethane, not rained yet so cannot comment on it at all.

23 minutes ago, SteamyTea said:

GRP properly done will last 40 years.

 

Having patched up GRP boats and cars, it strikes me that it could be more successfully repaired than the other options as well?

1 hour ago, Radian said:

Having patched up GRP boats and cars, it strikes me that it could be more successfully repaired than the other options as well?

Is can, but these new PU resins are marvels of chemistry and can be applied in the wet.

I want to play with them, but missed the guy when he did the roof.

For me, having done GRP and rubber. Without a doubt it would be EPDM.

A decent installer will have no issues detailing the lantern and box gutters ( I'm assuming that's what you were describing) EPDM can sit in water with no detriment and can easily be patched if it gets damaged.

10 minutes ago, Jenki said:

Without a doubt it would be EPDM

After several year, can you safely stand a small scaffold tower, or ladder on EPDM?

Edited January 26, 20233 yr by SteamyTea

2 minutes ago, SteamyTea said:

After several year, can you safely stand a small scaffold tower, or ladder on EPDM?

Just protect the roof from any sharp edges and no worries. 

2 minutes ago, Jenki said:

Just protect the roof from any sharp edges and no worries. 

That is what we would do, but others, in the future...

1 minute ago, SteamyTea said:

That is what we would do, but others, in the future...

As an installer, bring it on😉

I visited a small developer friend of mine today and he was shocked when I said I was considering a grp roof. He swears blind by epdm saying that he’s had grp rooves twist and buckle and crack. Then I looked up and saw that his food lantern was clad in chipboard and I got distracted. 

Personally I would/have used several times EPDM. (we have our ASHP on it). 

 

Unfortunately/fortunately I will not be around to see if it lasts 50 years (5 so far), but if there's a problem with it, I'm sure I'll whinge.

 

Reading this with interest. I've used GRP in the past and was planning it again for my balcony. Is EPDM DIYable? Our roof was fleece lined PVC and after watching the guys do it, would not attempt it myself.

1 hour ago, Conor said:

Reading this with interest. I've used GRP in the past and was planning it again for my balcony. Is EPDM DIYable? Our roof was fleece lined PVC and after watching the guys do it, would not attempt it myself.

DIY able?  a competent hands on person should be ok and if you've done GRP -well,  then this will be a walk in the park .  there is some very good guides @ EPDM tutorials. a lot of the info in that lot is what they use on the course.

I've done quite a few EDPM roofs for myself in the past. The basic flat ones are a doddle. Add any upstands or penetrations and it gets a bit more complicated. I've not had a leak yet.

I have a fibreglass cover on an area of flat roof with upstands, and it is fine after 6 years.

But a big 400m2 roof we had done failed at joints (too big to absorb differential movement?), very expensively as the roofer had disappeared.

I therefore favour flexible sheeting with guaranteed seals.

For DIY I fancy the stuff that comes in tins  simply paints on and becomes a single flexible layer. But there seems less of it about so perhaps there are issues.

7 minutes ago, saveasteading said:

But a big 400m2 roof we had done failed at joints (too big to absorb differential movement

Could be a problem for any material.

There are flexible polyester resins, and with a suitable orientated weave, expansion joints could be made.

I am willing to work as your consultant about all stuff GRP.

Car patches to  building oligarchs' yachts?

2 minutes ago, saveasteading said:

Car patches to  building oligarchs' yachts?

Almost

Kayaks to Lord Weinstock country residence.

We’re using Alwitra Evalon V

alutrix followed by resitrix no brainer.