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Porch roof still leaking after hip and ridge tiles reset by roofer

Discussion in 'Roofing and Guttering' started by John McLaren, 9 Oct 2020.

  1. John McLaren

    John McLaren

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    Hi all. This is my first post so please be kind.

    In May this year our porch was showing a leak on the plasterboard ceiling where the porch wall meets the house. The porch is 12 years old, three sided into the corner of our L shaped bungalow, with a pitched, pintiled roof and two lead valleys.
    The lead valleys had new mortar fillets between lead and tiles fitted about 5 years ago and look in good condition
    In the roof I could see damp under the membrane on the hip rafter that sits above the house wall and this ran down into the area above the leak stain on the ceiling. The hip tiles mortar joints all looked a bit flaky so I had a local roofer that we’ve used before reset all the porch hip and ridge tiles.

    From May until September we’ve had very little rain here in Suffolk and all seemed well with no sign of the leak.

    After the heavy rain we’ve had these past few weeks the leak stain reappeared on the porch ceiling and started spreading. I looked up in the loft again and could see what appeared to be three leak sites
    One appears to be from the reset hip tiles again and I can see wet running down the hip rafter into the leak stain area
    Two appear to be from the reset ridge tiles as the membrane has damp patches running down from ridge to the valley board. Looks like the water is then caught in the valley mortar fillet, soaks through the membrane and runs down the valley board to the area above the ceiling leak stain.

    The porch roof tiles and mortar joints on the ridge / hip tiles look perfect on the outside so I’m struggling to decide what to do next. I had thought of waiting for a dry spell and then blasting the whole roof with Thompson’s Water seal but Id rather get a proper job done.

    Any suggestions gratefully received

    Many thanks
    John
     

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  3. Barthy

    Barthy

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    Does the lead valley have a welt/tilt fillet?
    Out of curiosity what is the pitch of the roof?
     
  4. John McLaren

    John McLaren

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    Hi and thanks for the quick reply.

    There is no welt on the lead valley

    The roof pitch on the leaking side is 35 degrees

    John
     
  5. John McLaren

    John McLaren

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    Hi Barthy,
    The weather here is not so good for removing the porch valley tiles this next week
    Just wondering if I could remove the lead valley mortar fillets and use a mastic sealer to make a temporary welt down each side of the lead to tide me over the winter?
    Thanks
     
  6. Barthy

    Barthy

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    Weather in Portsmouth isn't too great either pal.
    I wouldn't advise it to be honest.
    Do you know the valley width I personally would recommend 450mm minimum with a clear 125mm channel in the centre.
    It isn't too difficult to strip and number tiles, make good or install sufficient lead valley (with small tilt/welt) fix fibre cement strips in line with valley tiles with flexible mastic and mortar the valley as before.
    Or alternatively opt for the fibreglass route.
     
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  7. datarebal

    datarebal

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    a couple of pictures showing the roof as a whole would be useful.

    Mortar work looks a bit amateurish maybe close up of that too.
     
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  9. John McLaren

    John McLaren

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    Thanks Barthy,

    The valley lead is 450mm and channel is about 200mm wide.
    Are the fibre cement strips meant as an additional barrier ?

    Cheers
    John
     
  10. John McLaren

    John McLaren

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    Hi datarebal,
    Thanks for the reply.

    mortar was replaced 5 years ago by a local roofer. He didn’t spot the missing lead welt/tilt
    I’ve added some extra pics showing the complete porch, valley mortar, damp area, wet valley boards, wet membrane.

    Cheers
    John
     

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  11. datarebal

    datarebal

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    Water seal will not solve anything.
    Re bedding the hips the other roofer may not have exposed the lead valley detailing.
    So would not know if there is turn ups.. Welts or anything else.
    Inside the loft there are a few nails poking through not good.
    You will need to strip out some tiles each side of the valley. There maybe a few damaged ones not obvious to you
    Once you ave exposed that area if its not damaged tiles , likely it could be excess mortar spread out over the edge of the lead. seeing as the valley mortar has cracked away from the tile cut edge. Water can easily track back under and onto the underlay which is damaged anyway.. welt or not
     
    Last edited: 10 Oct 2020
  12. John McLaren

    John McLaren

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    Thanks datarebal, much appreciated.

    Inside the roof I can see and feel the valley fillet mortar pushing against the membrane and bulging it over the valley board. The membrane is soaking wet just above the top of the valley board in a few places. This is running down the valley board into the corner

    in the picture where the hip rafter and valley board meet at the corner you can see water running down the left side short rafter that comes down from the hip rafter. Could this be coming from the hip ridge tiles or is it still likely to be water washing over the mortar the lead and soaking across?

    Many thanks
    John
     
  13. datarebal

    datarebal

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    if you can feel the mortar then its wrong and needs stripping out. the tiles should not be bedded directly on the lead anyway.
    As for the hip leak the pictures do not help a lot, could be damaged tiles as i said before. a few need to come out to see.
     
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  14. John McLaren

    John McLaren

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    Thanks datarebal and Barthy......wish you guys were up here in Beccles!

    The roofer who replaced the valley mortar 5 years ago is a nice guy. He’s done a few jobs for us and always tries his best to come out and help at short notice. He’s here tomorrow to take out the valley mortar and we can decide what to do from there

    Barthy, I understand the cement fibre strips now...thanks

    Guys......How should the roofer be re-mortaring the valley fillets to leave a gap to the membrane........or is that just skill?

    Many thanks guys
    John
     
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