Exterior Deck Construction

[rlewistx]

I have a project I’m designing for a camp that is a two story dining hall and meeting room building. The lower level is used for the meeting rooms and the upper level will be the dining room. The floor plan calls for a deck outside the dining room along two sides. The deck is about 18 feet wide. The architect would like the deck to be waterproof so that people can come out of the meeting rooms below but not get wet of it is raining. This tends to eliminate the traditional wood deck framing because water will leak through the gaps in the decking.

I looking for suggestions for a deck detail that can have an exterior exposure and provide a barrier for water penetration. This will have high foot traffic as it will be a place for groups to congregate. The main building interior floor framing will be steel beams/joists and concrete slab. I'm thinking this should be a sandwich type deck with a concrete slab, membrane and topping slab. I would appreciate any specific information on membrane and detailing specifications for the assembly. If the framing remains steel then I'm concerned about corrosion of steel. I could use a good epoxy enamel or perhaps galvanizing. Galvanizing sounds expensive.

Thanks for your help.

 

[paddingtongreen]

If you have the height, you could use a sloped cellular metal deck with membrane roofing, with a wooden deck above it.

This deck has been used for the roofs over turnpike toll booths in PA and NJ.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[PSlem]

How about simple catch under wood deck like

http://www.underdeck.com/

or

http://www.dri-b-lo.com

or aluminum deck like

http://www.lockdry.com

?

 

[msquared48]

There are flexible membranes out there, painted or otherwose, that can be applied over normal wood deck construction that uses 3/4" T&G plywood over the joists instead of strip decking.

Some can take heavy traffic, but it will still be a mainrenance item though.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[vandede427]

if he's willing to live without the traditional look, what about sloped gypsum topping over plywood decking?

 

[rlewistx]

Is gypsum topping a water-resistant wear surface?

 

[jhoulette]

Do not use gypsum.
I was happy with Dryjoist

http://www.wahoodecks.com/dryjoist/

Otherwise, I typically, design for 4" concrete, corrugated steel deck, and steel beams.
I've also seen a lot of failing decks that have used less than 3" of concrete.

Jim Houlette PE
Web:

http://www.evstudio.us

Online Magazine:

http://www.evstudio.info

 

[hokie66]

Compressed fibre cement sheets can be used instead of plywood. The joints are sealed with a fibreglass bandage, then the whole thing is waterproofed, followed usually by tiling.