[dwt]

I currently have a rooftop deck on a flat rubber membrane roof. Unfortunately its not a deck. Its a carpet on the roof with a railing system. I am going to build a deck so that when I have people over they aren't walking on my roof. There are post's for the railing but do I need a better support system? whats the best way to go about building this deck?

 

[AGWhitehouse]

5/4 decking or equal with a piece of 2x4 laid-flat running perpendicular every 16" or so. rest the 16" o.c. "joists" on walkway pads that can be purchased where you would by the roofing material. The deck shouldn't be attached, but rather just resting on the roof surface with the walkway pads being the protective member between the deck system and the roof system

typical walkway pad:

http://www.online-buildingproducts.co.uk/resources/6C/1900/picture/10/17058832.jpg

 

[dwt]

re: building roof deck

Thanks. My original thought is to have it elevated about 6 to 10 inches off the roof. Would I float the support posts or bracket them into the roof. The goal is not to have any punctures in the roof. I've read that putting the support posts up with a "cushion" underneath it works fine as the weight of the deck will keep it stable. Thoughts?

 

[AGWhitehouse]

You should make your deck system and rails totally independant of your roof. Brace the rails to your decking joists. I wouldn't recommend "post" as the point loads on the membrane won't be so good for it. If you want to raise 6-10" then think about building a tradition type deck frame with 2x6 or 2x8 joists. Then just lay the walkpads under the joists. That way the load is dissipated over the entire joist surface and the roof will thank you for it.

 

[user1007]

Floating as suggested makes perfect sense but where are you? Better check code and possibility of variances before getting too far along on this. Will you need a permit and inspections? In Philly, they were going to make me frame the deck off the bearing walls. And because of battles between the Hysterical Preservation People and the City, the City was not going to let me use the strength of the existing ones dating back over a hundred years. I had to be so far from the property line to comply with code.

Is this your building or are you just adding to the top floor you own? Careful. This was my other situation and I did pay for thorough drawings to calm other condo owners.