Drainage problem on fibreglass roof

[leonlikestrees]

Hi all,

I've got a fibre glass roof on a single story extension. It has a parapet at one end, and originally no gutter on that side. I presume the idea was that the water would run off the parapet, onto the roof, and then into the gutter that runs on the side.

The problem is, water drains off the wrong side of the parapet, and runs down the wall. I put up a bit of guttering (pretty badly), to see if it would fix it, but it doesn't, as there is no overhang, and so it runs behind the gutter.

I can see two obvious fixes:

1/ create a barrier on the top of the parapet, so the water is pushed back onto the roof; or
2/ add an extra layer onto the parapet that sits away from the wall so the gutter can collect the water.

In both cases, I have no idea what materials to use, and how to fix. I thought a lead sheet might work for option two, draped over both sides, but that seems quite expensive. I would just screw some timber to the wall below the fibre glass to provide the "kick" needed to flow the water into the gutter.

Any suggestions (or options 3+??)

Untitled

• leonlikestrees
• 10 Feb 2015
• 1

 

[leonlikestrees]

obviously not floating anyones boat, this one

Having spoken to my father in law, he suggests coping stones along the top, which sounds sensible to me.

The cheaper idea I had was to silcone a PVC strip along the edge, just to stop the water run off.

Any of you experienced guys have an opinion on either option?

 

[freddiemercurystwin]

I don't really understand what's going on, got any better photos?

 

[leonlikestrees]

water gathers on top of the parapet , and drips over the side and goes behind the guttering.

You can see where the water goes, as it's black (more obvious if you enlarge the pic by clicking on it.)

THere's no overhang, so the gutter I've put up doesn't catch the water.

What I really need to do is to stop water running off that end of the house.

Leon

 

[Nige F]

Go with your siliconed plastic strip idea Just make sure you use neutral curing silicone - NOT the stuff that smells of vinegar - it won't stick !

 

[ree]

Where your parapet top butts up to the main house wall, damp penetration stains can be seen. This, presumably, means that the parapet cover material didn't lap up the wall and that there is no cover flashing in place.

What is the situation where the parapet upstand meets the wall "inside" the parapet? On the "outside" the fascia seems to have been extended too far - how is it sealed?

These details will have to be dealt with no matter what solution you come to ref the parapet discharge issues.

FWIW:
There are water(?) stains on the render. Perhaps they are surface splash stains?
Its non Regs to discharge a waste into a RWP.
The Tee in the RWP is perhaps becoming blocked?

 

[leonlikestrees]

Where your parapet top butts up to the main house wall, damp penetration stains can be seen. This, presumably, means that the parapet cover material didn't lap up the wall and that there is no cover flashing in place.

The fibre glass goes up the wall, and the render over the top. It doesn't seem to have taken very well, but I don't have any problems from that area at the moment, it just doesn't look great.

What is the situation where the parapet upstand meets the wall "inside" the parapet? On the "outside" the fascia seems to have been extended too far - how is it sealed?

On the inside, it's continued across that whole extension - it's a continuous fibreglass roof. Seems to work fine on that side, which is why I think pushing the water back over there will be fine.

Regarding the outside, it's not sealed, it just overlaps the render (actually, right at the end, it's even stuck into the render, although I've separated that as best as I can.

These details will have to be dealt with no matter what solution you come to ref the parapet discharge issues.

FWIW:
There are water(?) stains on the render. Perhaps they are surface splash stains?

water definitely runs over the top - I can see it in heavy rain.

Its non Regs to discharge a waste into a RWP.
The Tee in the RWP is perhaps becoming blocked?

that's been there since before I moved in. I don't think there's any problem there. The reason I started investigating this is that I have a damp problem specifically on the outside corner of that extension.