New EPDM warm deck flat roof - finishing touches

Discussion in 'Builders' Talk' started by dee-b, Jun 11, 2018.

  1. dee-b

    dee-b New Member

    Hi All,

    I've recently replaced an old poly flat roof with a warm deck EPDM rubber one and would really appreciate some advice/ideas on how to finish the job.

    The new roof consists of:
    18mm OSB3 screwed into of ceiling joists
    Damp proof membrane
    100mm Celotex foil faced insulation board
    9mm OSB3 top deck
    topped with a EPDM 1 piece rubber top (stuck with adhesive to the top deck)

    Now I need to:
    - Add the PVC fascias to cover the extra wood/insulation height
    - Affix the PVC batons around the roof lip to allow the kerb + drip edges to be nailed in place
    - Affix the left + right kerb edges to stop rain going off the side
    - Affix the front drip edge
    - Put the guttering back up

    The thing I am having a hard time with is that I am unsure where/how to secure the new fascias and PVC batons in place as i have nothing at the lip to nail into besides the 9mm OSB...

    Some ideas i've had:

    For the Fascias:
    1 - Nail the fascias to the gutter board at/just below half their midpoint and then nail the batons into the top of the fascias however this may not be secure?
    2- Add another extension piece/replace the gutter board with a wider piece so it comes higher up the OSB/insulation however again this would only be fixed to the joists/18mm OSB which would be about 1/2 way up its height. Then nail the fascias ontop of this.

    For the batons/kerbs/drip edge
    1 - Nail these through the Fascia board and 'try' and get the nail to sit within the 9mm OSB (if it comes out of the top it will pierce the EPDM :confused:.
    2 - Have the batons/drip edge lower down so they are affixed to the gutter-board/18mm OSB3 rather than being at the roof lip (not sure if this would cause issues?) (+ i'd still have an issue with the left+right kerb batons going into the 9mm OSB edges)

    Some pics of the roof/drawings of what i've done can be seen here:

    Any ideas are appreciated!
  2. dee-b

    dee-b New Member

    I had the advice of adding a 2x1 baton to the lip of the roof to secure the PVC batons too however will still have the same issue of affixing the 2x1 to the 9mm OSB top deck :confused:
  3. Dr Bodgit

    Dr Bodgit Well-Known Member

    I have 50mm celotex on my cabin, fitted 50mm battens around the perimeter to (a) help contain the celotex (b) gives something to nail facias to.

    If you haven't added any timber around the perimeter (big mistake), can you affix battens underneath?
    BMC2000 and dee-b like this.
  4. dee-b

    dee-b New Member

    Hey Dr, thanks for the input, unfortunately I haven't got any batons around the perimeter :( so right now I have 3 layers that are all fixed in place, all runningright up to the perimeter (OSB, insulation then OSB).

    I guess I could look at cutting/scraping away a slot in the insulation for the 2x1 to sit into and maybe using some short screws to go from underneath the 2x1 and up into the top 9mm deck (rather than trying to nail/screw directly into the 9mm edge face).
  5. Dr Bodgit

    Dr Bodgit Well-Known Member

    I'd do along these lines, but screwing up into 9mm OSB won't last long as its not really thick enough and you risk puncturing the EPDM. Could screw and glue with Stixall or similar, then it won't move. Can you screw into the 18mm OSB instead?

    [Sorry can't see photos as at work and blocks them]
  6. dee-b

    dee-b New Member

    yea I was thinking about some kind of glue&screw job too.

    I could screw into the 18mm but that would mean that the batons would be at the bottom of the insulation rather than the top so when it comes to nailing in the drip edge and side kerbs they would be low down the roof rather than on the lip.
  7. Dr Bodgit

    Dr Bodgit Well-Known Member

    OK, fix battens to 9mm then, screw carefully and glue. My experience with Stixall is that is sticks stuff together very very well so can recommended it. You could also clamp the timbers in place, probably no need for screws then.

    Actually you could add Stixall to the rear and bottom sides of the battens too, then its stuck to everything.
    dee-b likes this.
  8. dee-b

    dee-b New Member

    [​IMG]Thanks mate, thats a really good idea and gives me a load more confidence that they are less likely to give way :D.

    For confirmation on what I mean/other inputs:


    I found the above image on Google which basically shows the same layout I have - the 2x1 support I am planning to add is represented by the white board which is against the insulation, the Youtube video associated with the pic doesn't mention how it should be secured in place either!

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