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Re: questions regarding transite roof decking

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Be aware that transite is an asbestos-containing material (ACM).  Once
disturbed, it can become friable (airborne particles).  This hazardous
material is regulated - at least in California - by a thick body of laws,
and can only be removed by contractors licensed to handle ACM's.  I would
advise not to change either its loading or to otherwise disturb without
the advice of such an expert.  Left alone and undamaged, it is a legal
material, and not generally considered friable.  Once disturbed, you may
be soon in the attorney's arena, and likely a no-win situation.

Russ Nester

On Tue, 29 Feb 2000 05:16:19 -0800 "Robert W. Williams"
<robert.williams(--nospam--at)> writes:
> 	On a current project, a client has requested that I perform 
> an
> evaluation on an existing roof system for a primary freezer 
> facility. The
> roof which was constructed in the mid 1960s is comprised of 16" 
> steel joists
> spaced at 48" o.c. and corrugated asbestos-cement (transite) roof 
> decking.
> The transite deck has been filled with a lightweight concrete to 
> provide a
> level surface for the roof insulation. The client wants to put a new 
> roof on
> the freezer facility; however, they do not want
> to remove the transite decking. The roofing contractor plans to 
> strip the
> roof of its existing components down to the concrete
> leveling fill and install the new roof components. The new roof dead 
> load
> will be approximately 50% of that of the existing.
> 	With the new roof dead load being decreased, one should feel 
> pretty
> safe about leaving the transite deck in place; however, I am 
> concerned about
> the integrity of the transite panels. Based on a site visit, the 
> decking
> seems to be in good condition with no visible signs of flaking or 
> cracking.
> Based on a visual examination is it safe to assume that the deck 
> still
> possesses it strength characteristics. 
> 	For the roof analysis I would like to run some quick 
> deflection
> numbers on the existing transite deck with the new roof dead load 
> and live
> loads as required by the current building code. Unfortunately, I 
> know very
> little about the material properties of transite. What is it's 
> modulus of
> elasticity. 
> 	I have searched the company library and have not found any
> information on the transite decking. For comparison purposes, it 
> would like
> to find some older vendor information on these transite deck panels 
> (
> section properties, load tables,
> etc.). If anyone has any information on 3/8" thick decking with 3" 
> deep
> corrugations spaced at 4 1/2" center to center, I would greatly 
> appreciate
> it. My fax number is 404-370-3646. Any recomendations regarding 
> regulations
> or other concerns would also be helpful.
> Thanks for the Help.
> Rob Williams
> AGRA Simons Atlanta
> Associate Engineer, Structural
> robert.williams(--nospam--at)
> (404)370-3564