Roof waterproofing

[fozzie52]

Hello,

I've been having a saga with this roof which has been leaking. It's a lean-to extension. I found a hole in the membrane, which is nice, id just like some guidance how to beat close it up now please.

First off, does my cover-up look alright?
Should I put a bead of something along the top edge of the fabric where it meets the wall?
Should the fabric not sort of "tuck in" into the wall a bit so water drips onto it and not further down the wall?
Any other waterproofing tips?

I've bought a waterproofing plasticiser for the mortar. When the pros did it it came away from the wall though.

Thanks.

 

[Deluks]

Looks like a nightmare to flash, surely water will run down between the cobbles if they extend down the wall?
Mortar alone won't guarantee it to be watertight either.
Is there a chase for flashing the full length of the roof?
Stepped flashing would be a good idea lolat the internal corner, like on a chimney stack on a rooftop.

 

[fozzie52]

Looks like a nightmare to flash, surely water will run down between the cobbles if they extend down the wall?
Mortar alone won't guarantee it to be watertight either.
Is there a chase for flashing the full length of the roof?
Stepped flashing would be a good idea lolat the internal corner, like on a chimney stack on a rooftop.

Yeah, I guess I just thought there'd be something more substantial to stop water running down the wall, but clearly not because it's been leaking the whole way along nearly. I'm just not sure the best way to proceed now...

 

[robinbanks]

The blue/black fabric you're referring to is not the waterproof layer for the roof. Just checking because you're talking like you want to embed it as you would a flashing because it will always have water reaching it and be responsible for discharging it - it's not its design intent

The wall design as is will indeed be awkward to flash, but absent any desire to rebuild part of it to incorporate a flashing, or pointing it up so the depth of irregularity is less, a deep and consistent cut into which a flashing can be tucked would perhaps be best

 

[fozzie52]

But water will run down the fabric right? Because for one thing there's big gaps between these tiles, and tiles broken in 2, which I wasn't worried about because I thought this fabric would sort the rest out. Is that not the case?

 

[Deluks]

If that were the case we would just all clad our roofs in broken tiles.
Whilst you are doing the flashing, replace any defective tiles.

Yes the fabric is designed to save you, until you can carry out repairs. Think of it like a spare tyre.

 

[Deluks]

I'm presuming that behind those stones is more brick?
It might be an idea to carefully remove a band of the stones back to this, and cut a proper chase.

 

[fozzie52]

I'm presuming that behind those stones is more brick?
It might be an idea to carefully remove a band of the stones back to this, and cut a proper chase.

I don't think so, it's a very old house. In other places I've pulled the plaster out from inside and there's flint behind.

 

[Alastairreid]

The gutter hook above that corner has corroded and collapsed make sure the gutter is still draining properly.
The roof above that corner needs looked at.

 

[fozzie52]

The gutter hook above that corner has corroded and collapsed make sure the gutter is still draining properly.

Yeah i noticed that. The gutter has been cemented in though. Going nowhere.

The roof above that corner needs looked at.

Oh no. In what manner? Yeah that is a hole under the lead But anything else?

 

[robinbanks]

Yes the fabric is designed to save you.

But also, makes it a lot harder to a) know you have a leak and b) pinpoint where the fault is, as by the time water appears inside, dripping through eg a nail hole, it has potentially tracked far from eg where it breached the tile layer

But anything else?

Looks a bit ropey there:

 

[23vc]

The headlap on those tiles looks absolutely tiny if I’m seeing the pic right