Ok.. Addition to the house. roughly 1200 square feet, rectangle. Bedroom/Bath, 2 Car garage, mudroom... all above grade. The roof has to double as a deck. 100% flat.

I live in the Hudson Valley.. Now.. I know i can use a rubber roofing system for the "flat issue".. but can any of these roofs also double as a deck? Can I put decking materials over it?

 

I have seen good roofs ruined due to use as a walk deck.... Occasional foot traqffic may not be a problem.....Its those lawn chairs and tables with sharp legs, etc.....Some things you need to be aware of......First, is the structure designed for the weight of people? If it is, then you are likely to have AT LEAST 3/4" decking, hopefully more like 1 1/8" T&G plywood, glued and screwed. Next, you likely will find that any roofer and manufacturer will void all warrnties if used as a walk deck.
Unless you install a walkdeck material, you may have some problems......I normally recommend that a good roof be installed, then build a walk deck on top using redwood or Trex or some such material...... With the size you have it can get pricey. The walk deck should "float" on the flat roof, not be attached and should be modular so you can remove sections to service the roof...... This needs to be done right from the start or you will have neither a good roof or a good walk deck.......

 

thank you for that ...
having the deck float makes sense.