hehehe...my oldest 'princess' also has a balcony from her bedroom, sitting on top of the family room. I don't know what they're planning on using, but I've been very very clear with them that water intrusion is my biggest concern (4 decks/balconies), and so they're doing alot to slope the floors. The bigger balconies, they'll slope towards a floor drain. I would love to hear the 'proper' way to build a balcony, as well.

The longest leak free balconies I have encountered used EPDM membrane and wooden framing to walk on up off the EPDM.

One clients is going on 35 years, and while the wood has been replaced twice the EPDM under it is doing just fine.

I'd have a flat roof company install a roof, and then install a floating floor on top, teak or redwood with a pressure treated frame underneath. There's a Holmes on Holmes that had one of these.

the specs on our plans say "dex o tex" and that's it. No real other specs as far as a layer of this over a layer of that, etc. I googled it and it's also a membrane. is EPDM better? Should I try to request that instead?

Depending on what dex o tex product they use and how well it is applied it should work.

The problem with 'liquid membranes' always seems to come down to application skill.

Well, I'm a little old to be a princess, but I do have a small porch off my upstairs office. We also are very concerned about the sealing and they have put a membrane down (don't know the brand.) A company rep brought out a sample of Azek Deck the other day (He was there to look at a problem installing our Neuma french doors.) We are going to use Azek deck on our upstairs porch. Website is www.azek.com. I also had posted on the porch forum but got no response about sealing properly.

"...they have put a membrane down..."

The most common one for residential is usually bitumen.

It is very thin and has a relatively short life.
Seam failure is the common problem.

EPDM is not really marketed for residential use, but there are a number of places that sell factory seamed pieces that can be rather large.

It is used to line fish ponds also.

The EPDM membrane itself has a life of over 35 years.

Mechanical damage is its biggest problem, not sunlight, heat, or cold.

Brickeyee, I hope you are still following this year-old thread.

Would there be a big difference in the heat gain from using a black roof (EPDM or torch down) compared to white or gray/silver colors on a flat roof (about 1.5 inch slope over 13 feet). The roof has about 8-9 inches of fiberglass insulation below the deck? Other products, such as PVC and TPO are available in white, but are more expensive than EPDM (not sure how much more); and I am trying to see if the difference is worthwhile.

I am in Maryland, near D.C. The roof to be replaced is terne metal (steel coated with a tin/lead alloy) coated with fiberized alulminum roof coating.

Depends on the area.

You can put a protective layer over the EPDM and then use colored gravel (white being the most common).

A smaller outfit was making EPDM that was not black, but I have not seen it or used it.
It could affect the long term UV resistance also.