Re: [GBlist] PLYWOOD ROOF DECK

[Sarah Holland/David Foley <hollandfoley@acadia.net>]

on 04/18/2002 12:34 AM, David Seth Melchert at dmelchert@earthlink.net
wrote:

> Alan:
> 
> Perhaps this is because T-111 is not rated for decking at all. It is a
> siding material. The lapping edges (not t&g) would be the first clue.
> 
> Seth
> 
> Alan Abrams wrote:
> 
>> can anybody advise me on the structural properties of 5/8" T-111 type
>> (yellow pine) panels as a roof deck with the following green roof
>> application:
>> 
>> the panels would be applied directly to wood joists @ 24" oc.;
>> with a membrane roof and 16mil poly root barrier applied to the panels;
>> then, (4) layers of 2" extruded ps insulation;
>> filter fabric;
>> hydrodrain;
>> last, 4" extensive soil mix and plantings
>> 
>> I've searched the APA site, but cannot find (or recognize) the specs for
>> t-111.
>> 
>> Thanks in advance
>> 
>> Alan Abrams
>> (designing his first green roof)

Alan,

I'd second the Seth's suggestion that T-111 isn't appropriate for this
application - were you assuming that the grooves in T-111 would help with
drainage?  T-111 isn't APA rated as a roof deck.  I think a
tongue-and-groove product such as "Advantech" might be better.

My other concern is the load you're proposing for "wood joists @ 24" oc."
With our Eastern Species of framing wood, this sounds problematic,
especially for a low-pitch roof that would be subjected to snow loads at
certain times.  I've forgotten your location - are you in snow country, and
are you talking about strong lumber, such as Douglas Fir or Oak?

- David Foley
-- 
Holland & Foley Building Design L.L.C.
232 Beech Hill Rd.
Northport, Maine 04849 USA
p: (207) 338-9869 f: (207) 338-9859 e: hollandfoley@acadia.net


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