GRP Roof Help Please

Hello,

We have recently had a new Garden Room made and the builders have used a GRP Roof. The roof is 4.5m across and they used a 30mm furring strip. The water does not drain. When we pointed that out they went up and poured a load more resin on where the water was pooling which simply moved the puddles and subsequently have then done the same again. Now they are simply saying it is not an issue and won't leak so have done their job and want payment.

I would be interested to know some of the experts on here's views please.

I have attached some pictures.

Thanks for your time.

The same resins and topcoats that go into your GRP Roof (albeit slightly adapted) have been used in the marine industry for over 40 years to make boats, yachts and lots of other things that float, so to have water on a GRP Roof, while not ideal is not usually an issue if the roof and the system have been installed correctly.

Whilst not ideal It won't do any harm at all. As the poster above said your roof is made from the same material as bath tubs and boats, so it will be fine. Also, it looks like that is as much puddling as you will ever get as if it gets any deeper it will drain off the roof anyway.

Your builders have cocked up. The fall on a 'flat' roof should be no less than 1:80, so your 4500 roof should have had firring strips of 60-odd mm.
Presumably the room was small enough to not require building regs, which in this case is a shame.
If builder designed the roof then he should take it off and redo it- he won't want to because the roofing sheets will not be reusable and it'll take some hours.
The above posters are correct- long as the grp has been applied properly it won't leak. It will be a nuisance when wind blows the water off the roof, if there are any pinholes or defects in the topcoat then frost damage will accelerate their failure (if water didn't pond it won't be there to freeze), the ponding will make the subsequent leak worse.
Invite your builder to correct his mistake. Properly. If he declines then get a price for doing the roof with the proper fall and take that sum off what you owe him.
It'll be a chunk of change- its important you gather all documentation to do with the job now in case he decides to go legal.

Thank you all for your responses on this matter. Yes the building is a touch under 30sqm so small enough regs were not required which in hindsight is a real shame. The builder did both design and fit the roof so I have reverted to him and await his thoughts.