Supporting Steel on Roof
We need more dunnage on this roof. Is it possible to use 2 existing chimneys to support the steel? The top picture shows current steel in a triangular shape in the upper left of the roof. There is a noise issue with that location that can only be solved with a very elaborate sound abatement…
We need more dunnage on this roof. Is it possible to use 2 existing chimneys to support the steel? The top picture shows current steel in a triangular shape in the upper left of the roof. There is a noise issue with that location that can only be solved with a very elaborate sound abatement system that will in all likelihood compromise if not void the warranty of the 2 existing 5 ton units plus a twin fan condenser mounted after the photo was taken. The other possibility is steel placed between the far right chimney and an elevator shaft. Span is approx. 20 ft. give or take. OR do we need to punch down through the flat roof and access the tops of the walls?
a chimney is not a structural element…bad idea
Mod – it is doubtful that the chimney has the structural capacity to support the dunnage.
I’ll add based on JimHill’s response.
Chimneys are in great shape. Appox. 2′ by 5′. Is there a law expressly requiring that dunnage be supported by the foundation walls with no other use allowed such as a chimney? Furthermore is there any way to mount these units on the roof without steel beams sitting on the parapet.
“…dunnage at the rear corner, angled to span from the side bearing wall/parapet to the rear”.
Doing that now but there is a noise issue with the owner’s apartment that is requiring a move.
Thanks though.
The new fire code states that you must maintain a clear aisle six feet wide from front to back of a roof. It looks like you’re proposing to run dunnage all the way across the roof. To do that, you will need to have a non-combustible stair up and over the dunnage, like a bridge.
In addition, most brownstone chimneys I’ve seen lately can hardly support themselves, let alone dunnage. I would definitely stay away from using the chimney for anything.
Best solution is usually to put dunnage at the rear corner, angled to span from the side bearing wall/parapet to the rear.
Jim Hill, RA, LEED AP
Urban Pioneering Architecture