I am in the process of adding a large addition on my home. It is modern
in character and has a flat roof. The roof is a two layer system
(Firestone SBS Torch on top of Firestone APP 180) installed on tapered
insulation, over a plywood deck. It is less than two months old. I
live in Maryland, near Washington, DC. As it might relate to my
questions, we have hot summers and cold winters here!
The roof is surrounded by a parapet. All the drainage comes to a
single opening thru the parapet and is conveyed to a scupper installed
on the side of the new house.
After installation, I got up on the roof after a rainstorm and noticed
that puddles approximately 5 to 7 feet long and 3 feet wide and 1/2
inch deep are left on the roof. These puddles persist for more than 48
hours, although they get smaller over that time. However, the take
home here is that, after 48 hours, there is still standing water on the
In addition to this problem, I noticed a bubble approximately 1 foot
long and 2 inches wide in the cap sheet. It is in the middle of the
sheet, away from any seams or flashing.
My questions are these:
1. Does this persistence of standing water represent a problem? Is
there an generally accepted performance standard for flat roofs that
call for complete drainage after a certain time? If so, what is it?
The home improvement shows seem to indicate that this kind of roof
should be dry after 24 to 48 hours.
2. Does the bubble represent a problem that needs attention
While I thank everyone in advance for your responses, I'd really like
to hear from any professional roofers that might be out there. I'm
holding $8200 back at this point, so I think I can get my roofer's
attention on fixing these items, if warranted. Thanks again!