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Breathable membrane problem

Discussion in 'Roofing and Guttering' started by Ronob, 23 Jan 2019.

  1. Ronob

    Ronob

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    just been up in the loft, house is a 1920’s semi, and noticed that the existing membrane between the tiles and roof joist (rafters) is worn and torn in several places, some quite badly.

    Is there anything I can do besides have the tiles off the roof and relay the whole roof? - I don’t have a big budget for that!
     
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  3. noseall

    noseall

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    Is the roof leaking? What sort of tiles do you have on the roof?
     
  4. Notch7

    Notch7

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    Is it torn underfelt rather than breather membrane?
     
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  5. Ronob

    Ronob

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    Roof shows no sign of leaking, come to think of it, not sure if it’s membrane or felt, it’s old and where it’s torn it has the appearance of a black paper, maybe a pitch paper?? With the possibility of some kind of woven thin thread - couldn’t be certain of that (I need to put a light up there!).

    As for the type of title, I really don’t know, they are flat with a slight rough texture to then as if coated in sand. They are not the wavy sort - that’s the best I can do
     
  6. Ronob

    Ronob

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    Just looked at a builders merchant website and the tiles look more closely like the Redland plain concrete tile.
     
  7. wwwebber

    wwwebber

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    My house has no membrane whatsover and has no leaks. I have no plans to put a membrane in either. If you have no leaks then a torn membrane is not an issue.
     
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  8. datarebal

    datarebal

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    As above but add the felt isnt there to keep the rain out.

    Sounds like sisalkraft underlay. probably concrete plain tile
     
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  9. ^woody^

    ^woody^

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    What tiles are covering it? That makes the difference.
     
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  11. ^woody^

    ^woody^

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    That's odd. Why is it designed to waterproof - waterproof material laid in a way to be waterproof?
     
  12. datarebal

    datarebal

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    name a waterproof underlay, where it states waterproof on the wrapper...
     
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  13. Ronob

    Ronob

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    Yeah, I went to a builders merchants today and asked about underlay, they also asked if I had a leak because, they said, underlay isn’t for waterproofing, it is basically draft-proofing! And condensation reducing.

    Anyway, he had the suggestion that I buy a large sheet of polystyrene and cut it to size (width between rafters) and shove that in, which will add insulation - any thoughts on that?
     
  14. Mw Roofline

    Mw Roofline

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    I think that redland spirtech is fully waterproof but about £200 a flippin roll.
     
  15. datarebal

    datarebal

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    for how long?
     
  16. Notch7

    Notch7

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    Since a roof has loads of tile battens nailed through the membrane wouldnt it be pretty difficult to achieve water tightness -although I appreciate the rafters are the high pojnt since the membrane must sag a little between rafters.
     
  17. datarebal

    datarebal

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    oh really... 10 mm drape , some of the best known names can drip if exposed to any amount of rain
     
    Last edited: 25 Jan 2019
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