I have seen at least three options for building up a warm flat roof with EPDM.
The composite roof deck type boards have to have additional ply/osb on top if using EPDM.
I have also seen diagrams showing an additional overlay board between the PIR foam board and the EPDM.
So here are the options:
Joists-Firings-18mm OSB3-VCB-120mm foam board-EPDM
or
Joists-Firings-126mm Temp Deck (foam, VCB, 5.5mm ply)-12mm OSB (specified only if using EPDM)-EPDM
or
Joists-Firings-18mm OSB3-VCB-120mm foam board-12mm OSB (overlay board)-EPDM
I think the temp deck boards work out a lot more expensive especially if the extra 12mm OSB/ply is required...
Any thoughts on this?
The composite roof deck type boards have to have additional ply/osb on top if using EPDM.
I have also seen diagrams showing an additional overlay board between the PIR foam board and the EPDM.
So here are the options:
Joists-Firings-18mm OSB3-VCB-120mm foam board-EPDM
or
Joists-Firings-126mm Temp Deck (foam, VCB, 5.5mm ply)-12mm OSB (specified only if using EPDM)-EPDM
or
Joists-Firings-18mm OSB3-VCB-120mm foam board-12mm OSB (overlay board)-EPDM
I think the temp deck boards work out a lot more expensive especially if the extra 12mm OSB/ply is required...
Any thoughts on this?