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View Full Version : Residential flat roof venting/flashing requirerments



Don Rataj
02-27-2009, 09:21 AM
1) 2 story multi family with TJI roof joist (min flat slope) with drywall to the underside and batts insullation between the joist with modified bitumen roof.
BOCA called this area between the joist and the flat roof an attic.
Attics need to be vented but this area was not vented per the constrctuion drawings.
Is the architect responsible for mold build up on the ceiling due to this enclosed space?

2) Membrane roof (same building) installed pprior to pararpets being completed and flashing was installed with wide caulk joint (by possibility the masons latter) Acceptable? Roofer did not return to complete project.

Jerry Peck
02-27-2009, 09:32 AM
1) 2 story multi family with TJI roof joist (min flat slope) with drywall to the underside and batts insullation between the joist with modified bitumen roof.
BOCA called this area between the joist and the flat roof an attic.
Attics need to be vented but this area was not vented per the constrctuion drawings.

That is an attic area, yes.


Is the architect responsible for mold build up on the ceiling due to this enclosed space?

It would probably cost more to try to hold the architect responsible than to address the problem. When were those units built?


2) Membrane roof (same building) installed pprior to pararpets being completed ...

That is not uncommon, as long as everything is done in the proper sequence with regard to the flashing of/to the parapet walls, which also depends on what the parapet walls are constructed of and what the cladding is.


and flashing was installed with wide caulk joint (by possibility the masons latter) Acceptable? Roofer did not return to complete project.

Not enough information to know, or really understand what you are describing. You may be describing the joint between flashing and counter flashing?

Any photos?

Photo of the approved drawing showing what was intended?

The flat/low slope roof needs to have a minimum of 1/4" per foot slope.