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Hi All,

I am considering adding a roofdeck to my building. The roof has a rubber/alumium roof with a slight pitch to the rear of the house. The party walls are about 18” with a cement cap.

Initially I was going to use steel I-beams that spanned the party walls so the deck was off the roof, but found that any builder using steel would add about $4000 to the cost of the deck. Several contractors said it is ok to build a deck directly on the roof. This is done by using a ½” roof pad under a platform system and the deck on top of that. The platform supposedly distributes the weight evenly on top of the deck. Lastly, one contractor suggested using a serious of palates that could be easily removed if/when I need to replace the rubber roof material.

During a renovation on my top floor, the ceiling was open and I got a look at the beams supporting the roof. I am not an expert, but the beams looked solid (no cracking, dry spots or insect damage) and my contractor also said they looked very solid.

I am considering hiring a structural engineer to test the capacity of the roof, but not sure I need to do this.

A Few questions:
1. Has anyone built a deck on top of the roof using the platform system (no steel), if so, any feedback regarding damage to roof, leaks or other negative results.

2. Has anyone used fiberglass as a roof material to seal roof AND for the deck? This procedure is used in ocean communities because most decks take a beating from the salt air. I have a contractor/roofer from south jersey who is Firestone certified who said this procedure would work well with rubber roofs. He’s done roof and deck work for me in another house and is very experienced and qualified (and honest). He wants to expand his business in Brooklyn.
FYI – None of the deck contractors I spoke to in Brooklyn mentioned Fiberglass as an option. They all want to use composite or wood.

3. Anyone have any experience with the composite deck materials: Trex, Azek, etc? any thoughts on slippage, staining, wear/tear etc? I’ve read the brochures, but would like real feedback.

4. Lastly, Has anyone had any experience with “Decks R Us” good/bad?

Thanks in advance.