15) A Living, Green Roof

The roof of the main building is pretty standard. In keeping with the design aim to have the roadside look of the cottage resemble a classic Cape, we opted for asphalt shingles that are somewhat reminiscent of slate, the traditional roofing material for Vermont homes of a certain age.

But we were in a real quandary as to what to do to roof over the hot tub room. Our designer had a pretty mainstream look, a slanted gable roof with a center cupola. Roofing materials to be metal standing seam.

But I'm pretty much opposed to this type of metal roof for a number of reasons: 1) the snow slides off quickly and piles up on either side of the building, 2) after a few years they can rust, 3) they're noisy. It turns out that snow is actually an excellent insulator, why you would want to have it slide off and expose the roof to the cold winds is beyond me. Even if we used asphalt shingles, the look from the main floor out towards the fields to the south would be less than optimal. Who wants to look down on a close-up look at asphalt from just a few feet away? Plus in summer it could get pretty hot.

I had looked into a couple of interesting alternatives. One was copper. It's expensive, but this roof is only 14 by 14 feet square, and since the view over it is probably the most visible of the different aspects, it seemed worth considering.

Then I learned of a company that creates stainless steel shingles. Think the Chrysler Building:

Maybe the Art Deco look would be pretty cool. But on reflection, (pun intended) it seemed that their glittery reflectiveness just might yield too much shine in your eyes.

Then while reading a copy of a solar magazine I caught sight of an article on green roofs. My first take was that it was about roofs that are created using green environmentally sustainable materials, maybe used tires or cardboard or something like that. On further reading, I learned that what they were talking about was also called a Living Roof. What? It's alive? Totally! A green roof is one in which dirt and plants replace metal or oil by-products. Sounds mighty intriguing... So I delved right in, searching the internet for all there is on roofing your house with plants. It turns out that green roofs are nothing new, the Vikings had them, they went even farther back in neolithic Scotland. And we've all read about the sod-covered roofs used by the pioneers on the Great Plains. I'm pretty sure the first European roof in America, on Leif Ericson's longhouse in Newfoundland, had a green roof.

This primitive technology has many benefits that are applicable today: less greenhouse gas emissions, the moderation of heat transfer, reduced stormwater run-off, summer and winter insulation, and, best of all, a habitat for flora & fauna. You know, there are really 6 benefits, they forgot it's going to be beautiful!

So I was sold. A green roof addresses many of the cons of the other choices we'd considered. It doesn't rust, it holds the snow, it looks great, and it's natural. This page sums up many of its pros: Why a Green Roof? All that stood in the way to implement this elegant solution was to talk my wife into it, not to mention the designer and the builder. Fortunately after much wheedling and convincing, they warmed up to the idea.

A green roof is not without problems, the major one being sheer weight. 8 inches of wet dirt over your head isn't something you want want to take lightly. Unless well designed and constructed, it can leak. Then there's the difficulty of keeping the plants healthy and growing. It turns out that irrigation is critical. Plants like to grow in Mother Earth, that's how they've evolved. Sticking them up in the air in a shallow box and having them survive isn't easy.

Actually there are two types of green roofs, extensive and intensive. The former is easy and cheaper to create, it features low soil depth, from 1 to 4 inches, and the vegetation of choice is the sedum, also known as the stonecrop. A hardy plant native to desert regions it's easy to grow and maintain. Unfortunately I think they're extremely ugly, more importantly they're non-native.

Extensive roofs with 8+ inches of soil allow you to grow almost anything, even small trees. To minimize the maintenance requirements, what we envision is a set of native wildflowers and perennials such as Black-eyed Susans, daisies and day lilies.

You can see from the above diagram that building a successful green roof is pretty technical, numerous layers of permeable fabrics and membranes that are necessary to make it work. What's not shown in the graphic are the drainage pipes that are required to shed water during downpours, and to make sure the plants don't drown in a muddy mess.

So once again, that's the plan, only time will tell on how it turns out. "The best-laid schemes o' mice an' men Gang aft agley" as Robbie Burns once said.