March 2001 - I found out about greenroofing from an article in the NYT, and called Bureau or Environmental Services to find out more. I borrowed Building Green from Tom Liptan at BES and got promotional materials from a couple German greenroofing companies. The pictures, especially, struck me. There’s something spiritual about creating green spaces where I thought none were possible. And I wanted to become a part of the ecoroofing movement in Portland. I Took Tom Liptan’s Ecoroof Tour and talked with him about a possible ecoroof grant application for the Hawthorne Hostel. Tom is encouraging and suggests the very visible location may be an excellent choice.
Funding – May/June 2001 The application was easy and friendly and designed for first time Portland grantwriters, like me.
February 2002 Pouring New Foundation – Bruce Kenny of Berry Nordling Engineers gave us a preliminary estimate of what was needed to restructure the roof for the added Weight. This included increasing the size of the concrete footings supporting the roof. Brendon, one of our volunteers is building a concrete form to Bruce’s specs.
June/July 2002 Demolition of Existing Roof - Our structural engineer also determined that the main beams and rafters had to be upgraded to take the extra 20 lbs /ft2 we planned to be adding to the roof’s weight. Jake Rosenfeld volunteered his time and work crew to build us a new roof frame. But first we removed most of the existing roof.
July 2002 New Roof Framing Goes Up - Jake is totally amazing. A huge thank you for the volunteered expert framing services!
July 2002 During the roof “tear off” we cut out a small section of roof and compared its weight with that of an equally sized piece of ecoroof. The one and a half inch thick sample of ecoroof saturated with water weighed in at 4 lbs lighter than the old asphalt tile roof. We were pretty surprised. We thought the ecoroof sample would weigh at least 10 lbs more than the original roof.
After “New Rooof Framing Goes Up” – August 2002 - We installed a new 2x8” “fascia” to the edge of the roof. These will be hidden by 2x12”s that will stick up 4” above the “dripline” edge of the roof to hold the soil and drainage materials back. The waterproof membrane will get unrolled over the roof and down this fascia board, to become sandwiched between the two. This helps protect the fascia from water damage. The outside 2x12’s will rot out by the time the plants’ roots have established themselves well enough to hold the soil on their own.
High Quality Rubber Waterproof Membrane Installation. Cutting the first piece. We chose a material called EPDM. It’s synthetic rubber. It is this membrane that is often thought of as the heart of a successful ecoroofing system. It is more expensive than asphalt or tar, but lasts 30 or 40 years instead of 10. The materials for our system cost $1000.
Laying out the membrane over a section of the new plywood roof. We’re ecoroofing about a third of the roof first.
Jute anti-erosion matting is laid over the rubber waterproofing, to prevent slides in the rainy season. Then soil is spread 2” deep and the other half of the mat is unrolled back over the soil layer to prevent washout.
Spreading soil. It’s a mix called Rooftop 1-1, from ProGrow and consists of 33% compost, 33% perlite, and 33% sand.
Planting the roof. Eventually the plants will spread and form a “carpet” of vegetation that covers all the soil.
We’re planting four species of native Sedums and Yarrow. Sedums are a type of succulent growing well on other Portland ecoroofs.
Checking out the view from below. What makes this ecoroof unique is its visibility. Anyone walking, biking, or driving on busy Hawthorne Boulevard can see how beautiful vegetated roofing can be. We are proud of our first third of ecoroof and are ready to begin greening the rest of the porch and office roof.