Flat roof issue

Discussion in 'Other Trades Talk' started by quasar9, Feb 9, 2020.

  1. quasar9

    quasar9 Active Member

    First post here, but before I start, my hats off to all the regulars for giving up their time to help others. Educating others and sharing your knowledge Is the greatest gift you can give. Been reading this forum for a few years and have learnt quite a bit.

    Issue with a 5 year old flat roof with Velux (genuine) windows built into light wells ( if that’s the correct term).

    1. At one corner, at least the top layer of felt seems to be lose and has bubbled up. This slightly dams up the drain and causes ponding. Although not deep or leaking I need to get this sorted as soon as weather improves.

    2. The Velux. When raining heavily and wind towards the window, some water ingress in the bottom corner which runs down the side.

    I will be getting a roofer to look at this but what is the likely cause and suitable fix for this ? Need to gen up so I can ask the relevant question before agreeing to the job
     
    Astramax likes this.
  2. KIAB

    KIAB Super Member

    Suitable fix,rip the lot off & replace with a GRP roof,done correctly it will last 40 years or so.

    If water has got under the felt, then it will eventually rot the decking, leak might not be large enough to show signs,in the ceiling of the room below straight away,could be months, or longer.

    [​IMG]

    [​IMG]
     
  3. Jord86

    Jord86 Screwfix Select

    Daft question but are they proper Velux flat roof skylights or Velux Roof windows that have been monged up/adapted to function as a skylight? Also, is it definitely felt or an epdm rubber?
     
    KIAB likes this.
  4. KIAB

    KIAB Super Member

    Bodged!

    Need some photo's.:)
     
  5. quasar9

    quasar9 Active Member

    They look like the second photo. With velux supplied surrounds. Not bodged with with windows designed for sloping tiled roof
     
  6. quasar9

    quasar9 Active Member

    Photos in the morning. It’s a modern 3 part high performance felt, not EPDM for sure
     
  7. Jord86

    Jord86 Screwfix Select


    The peeling possibly means they didn’t apply enough adhesive or torch it properly, maybe even laid it on a day where conditions weren’t ideal, corners are always a weak point with felt. Check the surround/flashing kit on the velux, any seal which may have diminished slightly, etc.
     
  8. quasar9

    quasar9 Active Member

  9. quasar9

    quasar9 Active Member

    Obviously GRP seems to be the permanent fix, as KIAB recommends, as was a roofer I talked to this morning (he is a total GRP man and won’t touch anything else) but is there a short term solution, at least until the kitty is a bit fatter !
     
  10. KIAB

    KIAB Super Member

    You could look at Blackjack 905 All Weather Roof Coat a try (from competitor),give the area around base of upstand & the side of upstand, & any other problem area, one or two coats,will need to clear away standing water & brush area first before applying, can also use it with 100mm wide scrim roll/reinforcing tape to reinforce any seams.

    https://www.everbuild.co.uk/product/905-all-weather-roof-coating/

     
  11. quasar9

    quasar9 Active Member

    Thanks KIAB and Jord86. What I do with the area that’s unstuck and bubbled up? Cut it out and patch ?
     
  12. KIAB

    KIAB Super Member

    Without seeing it, difficult to be 100%,if it's just the top coat, then probably cut it cross fashion & carefully fold back flaps & work some 905 in there, then stick down the flaps,allow to dry then go over area with another coat.

    Trouble is if you start cutting it back too much,you might start dislodging larger area's of the felt & it starts lifting, if it's been poorly stuck down in the past.
     

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