[Greenbuilding] polycarbonate panels as porch roof?

[RT]

On Sat, 11 Jan 2014 13:20:18 -0500, Reuben Deumling <9watts at gmail.com>  
wrote:


> long, narrow, low-pitched roof I'm designing (5'x35').

> the flat, double wall variety as opposed to the corrugated stuff.

> Any reason not to fasten it like one would a metal roof?


For this application as well as the interior storms of Reuben's other  
query, my preference would be to use diverted-from-the-wastestream glass  
rather than plast-echhhh! ... especially new plast-eccchhh!.

For the porch roof, tempered glass salvaged from patio door insulating  
glass units (IGU) discarded due to failed edge seals would be ideal.The  
glass from three, 6-ft units would yield enough glass to roof-over the 35  
foot porch (including eaves overhangs) and unlike the plast-echhh!, would  
last forever.

Plast-ecchhh! is a crud magnet and over time the fine grit in the crud  
will abrade the surface of the plast-ecccchh! further exacerbating its  
crud magnetism eventually making the plast-ecchhh! butt-ugly to the point  
of making the owners want to rip the stuff off and replace it.

If the plast-ecchhh! is going to be installed in a locale that experiences  
freezing temperatures and snow, I'd be very wary of using it for a porch  
roof that is subject to ice and snow falling off the main roof if it's a  
two-storey house.

Plast-ecchhh! in freezing temps tends to be especially brittle and highly  
likely to get cracked by sharp impact.

But enough dissing of plast-ecchhh!

Proper installation procedures for twin wall polycarbonate sheet is  
provided my manufacturers.
ie   
http://www.green-tek.com/Downloads/Polycarbonate/GT%20Thermaglas%20Tech%20&%20Install.pdf

(Note the necessity for pre-drilling of over-sized holes for through  
fasteners. Not following the recommendation will surely result in stress  
cracks at the fastener locations.)

-- 
=== * ===
Rob Tom					AOD257
Kanata, Ontario, Canada

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