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Velux window leaking from underfelt?

Discussion in 'Roofing and Guttering' started by xdrive, 8 Mar 2021.

  1. xdrive

    xdrive

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    I have fitted keylite windows in new roof.

    I built the frame and then cut the felt out, folded it above the frame and stapled it as per instructions.

    I poured some water on felt above the windows and the water pours out from top corner cuts.

    Also I have fitted the window including tiles.

    IMG_20210226_164204_edit_103328208964440.jpg

    How do I rectify it?

    Cheers
     
    Last edited: 8 Mar 2021
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  3. Alastairreid

    Alastairreid

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    Post a pic with the flashing kit installed.
     
  4. noseall

    noseall

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    We always fit a water deflector above the roof window - usually after we have fixed the top flashing tray and before we fix anymore battens/tiles above the windows. It needs to be positioned so that any water coming down the roof is deflected onto the top tray or onto the the course of tiles that sits on the top tray.

    We use wide DPM and this needs to tuck under the membrane lap just above the roof window. Otherwise any leaks directly above the window (lead flashing, broken tiles etc) are going to be interrupted by the window and potentially leak in.

    You need to address where the water is coming from first.
     
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  5. datarebal

    datarebal

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    Looking at the picture .. the underlay will leak .
     
  6. xdrive

    xdrive

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    Can't believe keylite instructions would suggest cutting like this.
     
  7. catlad

    catlad

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    Have you fitted the felt collar?
     
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  9. xdrive

    xdrive

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    No felt colour. Instructions don't show its needed.
     
  10. catlad

    catlad

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    Back gutter?
     
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  11. xdrive

    xdrive

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  12. cdbe

    cdbe

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    Mine are keylite, I think I stood looking at those corner cuts of the felt, trying to picture where any stray water would go and then decided to order and fit the felt collars. I'd never fitted roof windows before and I'm sure most roofers, as have mentioned above, know exactly how to overcome this issue with suitable DPC or whatever tricks they use.
    I presume this is why the felt collars are optional extras - only a clueless newby would pay nearly thirty quid for what is basically about £1's worth of felt and 50p's worth of aluminium channel.

    IMG_20200409_125004376.jpg
     
  13. xdrive

    xdrive

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    i know what i would do if i were to do it again. The cut should have been made a bout an inch below the corner and also 10 to 15mm from the corner. That would create a small channel directing the water away from the corner and towards the side.
     
  14. catlad

    catlad

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    Those felt collars help stop your window frames rotting prematurely.
    They are not an optional extra in my opinion, I fit them every time.
     
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