[Greenbuilding] Green roof drainage question

[Chris Koehn]

Marylin-
How about a little squirt of heat with a small bit of electric heat tape? Gardeners around here use them (along with row covers) sometimes to warm up beds for earlier spring planting. You could set this up on a timer, a T-stat, or simply plug it in when needed.
Uses some electricity, but pretty efficient and cost-effective in the big scheme of things.
<http://en.wikipedia.org/wiki/Trace_heating>


Chris
TimberGuides Design & Build
Van Isle

Marylin wrote
..:"Here's the problem, best as I can state it. 



When I had my green roof put on the addition to my home, the roof came
higher than the place it would have been without due to necessary
engineering, so the 'ground level' is only about 2 inches below the door
sill where I go out there. 
For a couple of years in a row now we have had much snow and a giant fast
thaw in February. 
What seems to be happening, best as I can figure out, is that the sun has
sort of 'glazed' the surface of the ground due to the sun and cold so when
the rapid thaw hits, the water cannot get to the normal drainage channels,
and because the glazing has evened out the roof surface and counteracted the
roof drainage slope, the water backs up through my door and causes mucho
damage... "