[Greenbuilding] Green Roof under deck

[RT]

On Thu, 24 Jan 2013 17:34:24 -0500, Gennaro Brooks-Church - Eco Brooklyn  
<info at ecobrooklyn.com> wrote:

> 3" green roof on his brownstone plus a deck that sits 2' above
> the roof.
> I suggested a glass deck and green roof under it.

Unless the tempered glass is of the textured variety, an outdoor glass  
deck sounds like a slippery, falling-accident nightmare waiting to happen.

For  good idea of what will happen, take a mop and wet the surface of a  
polished marble or granite floor and then entice some people you don't  
like to walk across the floor.

OTOH, take that same tempered glass and use it to create a sloped glass  
over-roof and the green-roofed roof deck becomes an outdoor room that  
could potentially be used year-round.

Whereas with the glass deck any moisture landing on it would be a dreaded  
life-safety hazard, moisture landing on the glass over-roof becomes a  
harvestable, desirable, life-giving resource. In fact, some of the  
tempered glass could be used to create rainwater cisterns.

[Irrelevant sidebar which you may want to skip if your time is limited ]

Speaking of tempered glass:

A couple of weeks ago, on one of the porch roofs on my home there were  
some snow accumulations that were high enough to obscure the tops of some  
of the windows on adjacent walls.

Adjacent to the porch roof where there's a cantilevered glass canopy  
sheltering a walkway below, I noticed that a sheet of glass had been  
pushed off of one the longitudinal edge supports by the massive pile of  
ice and snow working its way outwards with the help of the sun and gravity  
so that the length of the sheet of glass was supported only at the ends  
relative to that edge ... making for a very surprising downwards bow in  
the , a deflection of at least 3" due to the weight of the pile of ice and  
snow sitting on top.

I was fully expecting that glass to explode and rain down a shower of  
(harmless) glass chunks if it were to get another pile of snow dumped onto  
it from a nearby steeply-sloped metal roof so I skeedaddled on up there  
and shoveled off the pile of ice/snow sitting on the glass and the porch  
roof.

[sidebar to sidebar: After I returned outside from going in to have a cup  
of tea, my dog Zhoq was peering down at me from a roof canopy on another  
side of the house. He had climbed up onto a pergola roof via the pile of  
show I had shoveled off of the roof and had been hopping around from one  
roof to another, sniffing out red squirrel trails.]

I remembered LL-man telling this List about how his Dad (a glass or window  
vendor) used to have a display setup where he'd run across the room and  
slam into a sheet of tempered glass and according to LL-man, the glass  
would bow about 6 inches with the impact but would not break. While I knew  
that tempered glass was tough (as when flipped through the air by winds  
and tossed onto boulders--with no breakage), I was a bit sceptical about  
its ability to deflect 6 inches over a ~6 ft span. I am less so now and  
will likely remain so until I try it myself.

Wonderful stuff, that salvaged tempered glass. Eh wot ?

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

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