Adding conditioned space under exterior concrete/steel pan

Client is interested in adding conditioned space under an existing exterior concrete over steel pan deck. As far as we can tell, there was no waterproofing placed on steel deck prior to concrete placement. Climate is eastern washington state, moderate rainfal, winter temps below freezing, some minor snow accumlations.

Will be adding warm-side vapor barrier and insulation but need suggestions on how to waterproof this assembly. Is there a successful history of applications of some sort of mastic or membrane to the underside of concrete pan in similar circumstances?

Hoping to get some feedback. Thank you!

I’m not sure I’m following you. Is the concrete slab and metal decking below grade, a roof, or what?

The easy answer is, you waterproof/roof from the topside, not the underside of metal deck. So the question remains, are you looking for waterproofing or roofing? Also, why do you feel you need a vapor barrier? Do the owners have a walk-in freezer, indoor swimming pool, sauna, or something along those lines?

[quote=“Cerberus”]I’m not sure I’m following you. Is the concrete slab and metal decking below grade, a roof, or what? DECK IS AN OUTDOOR SEATING AREA AT 11’ ABOVE GRADE AND CURRENTLY ACTS TO COVER OUTDOOR PATIO SPACE BELOW. CLIENT WISHES TO ENCLOSE AND CONDITION THE SPACE BELOW. INTENT IS TO KEEP EXPOSED CONCRETE SEATING AREA ABOVE WITH CONDITIONED SPACE BELOW.

The easy answer is, you waterproof/roof from the topside, not the underside of metal deck. So the question remains, are you looking for waterproofing or roofing? BASICALLY CONVERTING AN EXTERIOR CONCRETE/STEEL PAN “DECK” TO A “ROOF” SO I NEED TO WATERPROOF THAT ASSEMBLY.

Also, why do you feel you need a vapor barrier? Do the owners have a walk-in freezer, indoor swimming pool, sauna, or something along those lines? NO, WARM-SIDE VAPOR BARRIER IS REQUIRED BY BUILDING CODE ON EXTERIOR SKIN OF BUILDING. APPLIES TO ALL WALLS AND ROOF/CEILING ASSEMBLIES.[/quote]

I once did a house that had a large indoor pool,they used primer and one of Grace’s products to line the pool space (the walls & ceiling).

I think it was the stuff they use for foundations but I am not sure.

Anyone know of a good resource pertaining to Twentieth Century Art Movements?

Probably Jansen’s History of Art

I have been searching for a decent resource of knowledge on this subject.
Kudos for making this site available.