Ok, I am not a builder or even an "educated homeowner". I can put together bunk beds, but that it the extent of my "construction knowledge". So if it sounds like I don't know what I'm talking about, well... ;)

We're thinking about a rooftop deck over part of our house. We're pretty sure we're going with steel SIPs for the walls, and some kind of SIP for the pitched part of the roof (finished attic space).  I wonder...

1. Is it economical to use SIPs as the roof under the deck?
2. How would the weight of the deck/people walking on the deck be supported? Would it need a lot of extra horizontal beams or vertical support columns/load bearing walls? Right now we're thinking about 28' x 16' deck.
3. Is there a preferred type of panel for this situation? Ex. steel/OSB, EPS/PUR?
4. What additional materials would we need between the deck and the panels?


I know these are very general questions and we would need a structural engineer to design our particular plan. I'm mainly interested in the economical aspect. If SIPs aren't a good choice, what roof system would you recommend for a flat roof?

TIA!

Cindy

Cindy; Too many variables to make a determination on a forum, more specific info needed , one thing I would recommend: avoid penetrating roof with any fasteners, lay decking on sleepers SIPS are 3 x stronger than wood and a good choice for any flat deck

If you are using metal SIPs for the walls you might as well use metal SIPs for the the roof deck. They are well suited for that application. A high quality flexible membrane system over the panels will be required.

I would do a combination of what Jeff and Chris had mentioned. For long term durability and water-tightness you don't want to walk directly on the panels, but instead suspend a conventional deck above the SIPs on sleepers (beams that lay on the roof) and then apply a waterproof membrane between the sleepers that laps up the sides of the sleepers and then apply sheetmetal caps over the sleepers to make them and the membrane watertight and then apply your decking over that. Here's a diagram of the basic concept.

Simon,
Why not just lay a larger piece of the waterproof membrane over the sleepers in lieu of the sheetmetal caps?

Wes; I have had great success with fiberglass with a non slip surface as the roof and deck, extremely low maintenance and easy to care for. Is just like a boat deck. http://www.regaldecks.com/default.aspx

Wes,

I was thinking that it would be hard to make one large membrane sheet conform to all the undulations the sleepers would create and there would be a possibility of puncturing it on the upper corners of the sleepers. So, for practical installation purposes, it should be divided up into smaller sections that only have to make one U shape each. The sheet metal caps will keep their shape and hold the membrane to the sides of the sleepers if they should come unglued.

Chris, How expensive was the RegalDeck system? Have you got a square foot cost?

A fiberglass deck system like the one Chris linked to will work, but is installation sensitive being that it is a coating process that must be applied properly. Not sure how long they last. Fiberglass is rigid and can develop stress cracks and allow water to get in.

My sleeper system relies on it's geometry to stay watertight by creating channels to shed the water. The deck above shields the flexible membrane from the sun, hail, foot traffic, etc... and will move with the expansion and contraction of the roof. It's a longer term solution.

Alton; It was $3.50 per sq. foot

Chris, Thanks.

This link to photos of fiberglass sun deck http://www.myspace.com/steelsips/photos/9844717#%7B%22ImageId%22%3A9844725%7D

Alton; I have not used it yet, but I have looked a several Seal O Flex jobs and they look pretty nice too. http://www.sealoflex.com/projects_decks/TileLook