New EPDM warm deck flat roof - finishing touches

27 Mar 2018
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United Kingdom
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!
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I had the advice of adding a 2x1 batton 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:
Would it help if you could fix a board (20mm thick say) between the OSB layers at the edge (so that it's face would be flush with the edges of the OSB)? The insulation would need to be trimmed back somehow so this board could slot in place, so to speak. Is everything already fixed in place?
Hey Simon yea that would help but yea everything is fixed in place now so I guess my only real options are:

1) trim back the insulation to make a slot and push the wood in + use strong solvent adhesive to hold it there + maybe get some angled screws in the top and bottom for added support.

2) peel back the perimeter of the roof from the contact adhesive (not sure if possible without damaging it) so I can screw down into the new wood edge board
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Fix from side at an angle to fix to the bottom OSB. And come down from top , unless you've glued DPM right to the edge already? Ensure fixings don't protrude so DPM is protected. Otherwise something like Sticks Like Sh*t to secure at the top.

In any case, to avoid having to chisel out all that insulation you could use 4" (say) wide blocks as fixing points and just remove enough insulation for these. Fine until someone else comes along and tries to fix something new though :)

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