Marlou,
This is an interestingly timed question, because there are two code proposals for the upcoming ICC hearings in
One of the two proposals makes Table 1607.1 specify a 100psf for roofs used for assembly purposes (including accessible roof gardens) and 20psf for “roofs used for roof gardens”. The other fixes the new section to specify 100psf for any roof with landscaping, accessible or non-accessible.
Our proposal review group favored the option to set the live load to 100psf for all roof gardens, accessible or not. The general opinion was that there is enough going on with the typical landscaped roof (landscaping, waterproofing, rigid insulation, pavers/decking, curbs, etc.) that even if the roof is non-accessible (or has only limited access), the higher live load made sense. It allows a margin in dealing with the difficulty in, or uncertainty in figuring out exactly what the actual roof load is with all the “stuff” that goes into a roof garden.
Regards,
Gary J. Ehrlich, PE
Program Manager, Structural Codes & Standards
National Association of Home Builders (NAHB)
ph: 202-266-8545 or 800-368-5242 x8545
fax: 202-266-8369
From: Marlou Rodriguez [mailto:mbrodrig@mbrodriguez.com]
Sent: Tuesday, January 22, 2008 4:49 PM
To:
Subject: Roof Gardens Live load
We do several jobs were we have live roofs (roofs with a gardens, not necessary accessible after construction). Based on ASCE 7-05 table 4-1, the live load should be designed for 100 psf. Can anyone clarify if this is only for roofs with gardens that is accessible.
Any help would be great.
Thanks.
Marlou