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New EPDM flat roof with patches

Discussion in 'Roofing and Guttering' started by thesheep, 11 Oct 2021.

  1. thesheep

    thesheep

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    Just got a new EPDM flat roof installed by a professional.

    I'm looking at it and I know nothing about rubber roofs.

    I see these patches at the corner of the roof light and another long one. I guess this is normal to make the rubber fit around the raised portion of the roof light?

    What I notice, though, is that in some places the very edges of those patches are lifting slightly. It is just a couple of mm. So maybe it's fine. It's obviously watertight right now. But I'm just wondering if that's normal, wouldn't this mean that it starts to erode over time? The patch would start to lift more and more? Shouldn't they be stuck down a bit more smoothly?

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  3. ^woody^

    ^woody^

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    The patches are normal but look a little lumpy like there's lots of debris between the two layers.
    The edges lifting are typically lack of adhesive right to the edges of the patch.
    The long strip seems to be a repair.

    The bond is very similar to vulcanising which is like a welded joint, so should not ever lift like normal glue.

    Probably poor quality work rather than a poor job, but if these were Firestone registered, you could possibly get the local rep's opinion.
     
  4. thesheep

    thesheep

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    Thanks.

    Yeah I noticed the lumpiness too, strange.

    So the bond being like a welded joint presumably means that it might not matter too much if the edges lift slightly, there's still going to be a significant amount of bonded material and it shouldn't continue lifting off further over time.
     
  5. Vinty

    Vinty

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    The black patches are called form flash.
    They work on the same principle as patches on inner tubes do.
    The patch itself is uncured butyl rubber which is activated by a primer.
    If the edges are lifting it could be because not enough primer was used to activate the form flash.
     
  6. kingandy2nd

    kingandy2nd

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    I experienced some of the bubbles with the patches on my roof when i did it. I believe the primer wasn't fully tacked-off which lead to gases building up.

    Long strip looks to be fixing the cut where they've separated the membrane for the skylight. (Not sure why they did that).

    Priming right to the edge of the patches is a dark art, if you prime too much you get left with a visible band of primer, prime too little and the edges of the patch lift...but i don't think they'll get worse.

    Doesn't look like a great deal of time/effort was spent on the patches, but I doubt they will leak.
     
  7. thesheep

    thesheep

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    Thank you! At least that is somewhat reassuring :)
     
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  9. catlad

    catlad

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    Your concrete roof tiles appear to be sitting on the rubber which is not ideal!
     
  10. thesheep

    thesheep

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    Good point, I hadn't really noticed that. The rubber apparently has a fleece backing which makes it more robust, I wonder if that will help with the tiles sitting on it? I'm not sure what I can get them to do at this point, since the height of the roof is set. Unless they were able to somehow cut all the tiles so they are slightly shorter.
     
  11. catlad

    catlad

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    Another baton on top of the one they are hanging on would drag them back a couple of inches.
     
  12. thesheep

    thesheep

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    Good idea. I will raise it with the builders. Thanks.
     
  13. Notch7

    Notch7

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    Footprints are free
     
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