Why is this roofing membrane breaking down?
- Thread starter Safety First
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Is the pic not showing
?
No, it's showing. I just can't make out what I'm looking at...? Is the membrane fabric (breathable) type?
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Have you any idea of the type/brand of the membrane? It doesn't look like the breathable stuff I was using 10 years ago. What is stored in the loft?
Yes it's the breathable type. I will try to find the name. Nothing odd stored in the loft....
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Anything unusual external? Flues/vents/heat/UV light getting at it etc? Or perhaps condensation under the tiles is dripping off and carry something from the tile to the membrane. Could also be manufacturing fault
Can you show a close up of the membrane? Has it split all the way though? I recall the last time I peeled breathable apart it was a sandwich of what looked like two nonwoven fibre layers with a latexy kind of layer in the middle, whereas yours looks like just a latexy bit that is splitting, possibly bonded to a nonwoven on the side we can't see . If it were mine I wouldn't be hugely concerned as beyond catching condensation I don't consider roof membranes to be particularly necessary. If a roof leak is causing this then it's the tiles that shouldn't leak, not the membrane's job to carry it
Can you show a close up of the membrane? Has it split all the way though? I recall the last time I peeled breathable apart it was a sandwich of what looked like two nonwoven fibre layers with a latexy kind of layer in the middle, whereas yours looks like just a latexy bit that is splitting, possibly bonded to a nonwoven on the side we can't see . If it were mine I wouldn't be hugely concerned as beyond catching condensation I don't consider roof membranes to be particularly necessary. If a roof leak is causing this then it's the tiles that shouldn't leak, not the membrane's job to carry it
I am so grateful. . Thank you
My dad offered similar; that the tiles, if stable and intact do the work and the membrane is a more minor backstop.
I imagine it will still shed water...
Spot on also re the construction...The material is made of gossamer thin layers. These are coming apart. The one layer that is crazing is most easily seen in the pics, which are admittedly crap. I did think it was obvious what was on show, barring the brand.
My wife makes amazing bread. By eye, she could tell you, "not enough salt", "too much water" etc.
I'd hoped it might be a telltale presentation someone could spot.
Sure it will become clear in time...
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The brand is normally visible on the other side of the membrane, I'm sure rolled that way deliberately so as to advertise during the time that the membrane is on but the tiles not 
I've also often mused that membranes make leaks harder to fix, because the place where you see it dripping though can be a great distance from where it's breaching the tiles. Lost count of the number of times I've been digging around with a cable scout and drain cam taped to it, trying to follow a leak path up a membrane to get a roughly roughly on where it's coming in
I've also often mused that membranes make leaks harder to fix, because the place where you see it dripping though can be a great distance from where it's breaching the tiles. Lost count of the number of times I've been digging around with a cable scout and drain cam taped to it, trying to follow a leak path up a membrane to get a roughly roughly on where it's coming in
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