3 16 4 8 mm gap between boards.
Sleepers roof deck.
It s best to build the wooden deck in removable sections for cleaning and maintenance of the rubber roof and repair of the membrane if ever needed.
Sleepers are placed between the deck surface and the ground or slab below it.
The decking sits on 2x sleepers usually laid flat.
However i would highly recommend that you consider a that the epdm is lying flat on the roof subfloor without any sharp objects that can puncture the edpm once sleepers are laid over top and placed under load.
You could glue the strips tongue sleepers or just make them a bit wider and rely on pressure to keep them in place.
Roof top deck with sleeper system install guide.
You can do a floating deck and is really your only option.
This will provide the surface for you to attach the decking.
Next you will need to install a watertight epmd rubber membrane over the top of the roof deck for protection against water infiltration in place of roofing materials.
For a large deck where flat sleepers are too thin to taper you can use 2x4s or 2x6s set on edge.
Deck must be designed to ensure that proper drainage and air flow are maintained.
I d put down strips of rubber roof under the sleepers.
Decking laid directly over packed soil will rot quickly and wood laid over concrete rots as well when moisture is trapped between the two materials.
Trex recommendations when using with a sleeper system.
A set of sleepers supports the decking and allows moisture and air to flow below it.
A sleeper system is a substructure between a solid surface and trex decking.
1 4 6 4 mm minimum gap where the decking meets a solid wall maximum of 3 8 9 5 mm recommended.
It s a wash as the deck keeps the sun off the roof which is good but it also stores a lot of debris in under there.
Drainage access and airflow are critical.
Then you will install sleepers or flat 2x6s laid flat every 16 on top of the roof surface.
A properly constructed epdm roof should last 40 or more years.
For repairs and removal of debris joist system access may be necessary.
Attach the decking with screws so it can be removed later for inspection or.
To protect the roofing membrane set the sleepers on strips of epdm or rooftop walkway matting available from commercial roofing suppliers.
You can use 2x material laid flat or 4x material also as sleepers.
If you want the decking surface to be level the sleepers will need to be tapered to compensate for the slope in the roof deck.
Water must be able to flow through and away from the deck.