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Extension flat roof where it meets pitched garage roof

Discussion in 'Roofing and Guttering' started by burts, 29 Sep 2019.

  1. burts

    burts

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    I am building an extension at home and have a situation where my new proposed flat roof crosses in to my garage pitched roof. Photos attached. You can see the tile over hangs where the flat roof would go. I don’t want to cut the flat roof in as in do the tile as it will look off key and tiles will be under the flat roof (although I know it would be dressed in somehow)
    Am I best grinding the tiles back slightly at the level the flat roof will finish, cut fascia board in then put lead between the cut tile and the fascia board and then felt down over that lead?

    Or isn’t there an obvious way that won’t look rubbish?
     

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  3. noseall

    noseall

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    The bottom two tiles will need to come off. The flattie will gain priority in the flashing stakes. You will then need a short length of ply lay-board fitting with a cocking fillet built in as the flattie travels the short distance up the roof. All will be finished with a combination of lead, flat roof material and cut roof tiles.
     
  4. burts

    burts

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    I’d like to pretend I followed all that cocking fillet sounds like a type of fish breakfast
     
  5. datarebal

    datarebal

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    or arris
     
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  6. noseall

    noseall

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    Its a tricky detail and rarely wins design of the year award. But it requires a bit of skill and understanding of how water flows off a roof. Don't forget that you need to have the furrings and flat roof deck and insulation in place before deciding where the flashings will be located and the finished flat roof height will determine what you do with garage roof tiles etc.
     
    Last edited: 30 Sep 2019
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  7. noseall

    noseall

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    It may go up to the third tile depending upon where the highest pint of the roof will be and the finished thickness of the insulation etc.
     
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  9. burts

    burts

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    Nosall agreed that it requires some skill. I am a good tradesman but I wouldn’t be doing the actual roof and flashings etc as I have no experience in it. What I’m aiming to achieve is what you say, get it up to finished deck level with furrings and insulation complete but as you say tiles need to be taken back to the wall. So my plan for now really is I’ve measured up to where the finished roof deck will be and grind or remove the tiles to this point in order for me to finish the flat roof square without cutting anything in to a tile. I think I will then post a pic of where I’m at as if I can proceed I will. Thanks
     
  10. burts

    burts

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    Not really finding anytime to crack on which is killing me as it’s decided to poor down most the time ☹️. I’ve noticed 2 joists have are split at the end half way through for about a half a metre. Can I just put a straight metal strap top to bottom so it don’t move or hammer long nails through or am I going to need to replace them both? Also .... my fall on the roof is running across against the joists. It’s 7m. Can I screw the furrings to the deck with the vapour barrier inbetween as it seems that would be more stable than directly on the joists.
     
  11. burts

    burts

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    Right, so change of plan.
    I’m now having to go with a cold roof because by the time my firrings are cut to 1:40 over 7.4 metres already on top of a 10inch joist it’s just too high. Would end up being around 600mm fascia at its highest.
    What’s the requirements for a cold roof ventilation as I will have no soffits downthe sides for vents.
     
  12. noseall

    noseall

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    NOOOOOOOOoooooooooooooooooooooooo.


     
  13. burts

    burts

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    I’ve gone back to a warm roof
     
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