pre-cast beam system for a flat accesible roof
 

pre-cast beam system for a flat accesible roof
hello all,
recently i encountered this issue. is pre-cast beams with 2.5" thick overlay suitable for a flat accessible roof top? will water-proofing work on this? building is 100' long and 50' wide. ther will be insulation and water proofing.
many thanks,
kc
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first - the precast should be sloped to drain
second - even with a slope, leaks will form at the joints between precast members. you can tool the joints and caulk them but they will fail in a few years
for occupied space below precast, a plaza system works best. this involves the precast structure with a 2" topping-waterproof membrane system - drainage space - slip material - topping slab.
if the roof were inaccessible then you could just get away with a waterproof membrane system (epdm or hot applied).