Putting in a residential green roof

Gardeners have been trying to put plants on their roofs for centuries, beginning with the hanging gardens of Babylon.

  • Sep. 1, 2012 5:00 p.m.

We have been hearing a lot about green roofs lately, but mostly in the context of large commercial projects such as the new visitor centre at VanDusen Botanical Gardens and the waterfront Vancouver Convention Centre, with its impressive six acres of living roof.

It might even surprise you to learn that when you are shopping at the Canadian Tire or Wal-Mart just over the bridge in Port Coquitlam, you are also pushing your cart under some of the largest green roofs in the Fraser Valley, with the one on Wal-Mart occupying more space than two NFL football fields.

I have to admit that the current green roof trend really hasn’t trickled down to the average consumer, as I only know of a handful of gardeners who have tried small scale green roofs on their cottages or garden sheds.

So when I got an invite to an upcoming residential green roof installation from fellow horticulturist Kelly Koome of Green Earth Landscaping, I jumped at the opportunity.

Although I have had some experience installing large-scale roof-top gardens from my landscape days, this was before green roof technology had arrived here from Europe, so we were essentially creating traditional landscape beds on multi-storey buildings – with soil weight, drainage, root systems, plant hardiness and irrigation being our primary concerns.

Still, gardeners have been trying to put plants on their roofs for centuries, beginning with the hanging gardens of Babylon, built by King Nebuchadnezzar the Second for his wife in the 7th Century BC.

On a more practical scale, sod roofs (stripped from nearby meadows) were once common in Scandinavia and much prized for their insulating value – these would eventually find their way to the Canadian prairies with some of our first immigrants.

Today’s green roofs are carefully engineered products with modular growing trays, precisely blended growing media (with only seven to eight per cent organic matter) and specially selected plant species chosen for their hardiness, durability and shallow root systems.

The green roof installation I was viewing with Kelly was the Calvert residence in Coquitlam, a recently built home with a definite West Coast feel to it. The flat roof they had chosen to cover was a 20-by-30-foot area overlooked by a small patio and a room with nearly floor to ceiling south facing windows – so they would have a perfect view of their new garden.

They chose the LiveRoof hybrid green roof system, which is provided by NATS Nursery of Langley.  The trays were custom-grown for the Calverts and they were actually able to choose which species they wanted, settling on a blend of several evergreen and herbaceous Sedum or Stonecrop – these were started back in April and they were given regular updates from the nursery.

By the time I arrived, the existing area (with a standard two-ply roofing pigment) was already prepped with a layer of 10 millilitre plastic and drainage mats, carefully configured around the drains.

The finished LiveRoof modules and edging materials were crane-dropped directly onto to the roof in specially designed Hoppit racks. The installation (which must be conducted by trained installers and, in this case, the Calvert’s son) is relatively easy, starting with the placement of the Permaloc edging system, after which the trays are simply placed in sequence, the soil elevators removed (this allows for soil contact between trays), then the finished green roof is simply watered to allow any loose soil to settle.




Mike Lascelle is a local nursery manager and gardening author (hebe_acer@hotmail.com).


Just Posted

Located on Airport Way in Golden Ears Business Park.

Located on Airport Way in Golden Ears Business Park.

MacDuff’s Call: Compassion within our communities

Support for Alisa’s Wish Child and Youth Advocacy Centre.

Ridge Jr. B Flames making additions

Four players sign, two coaches join mix.

UPDATE: Two-vehicle incident on Abernethy Way, Maple Ridge

Road near 227th Street reopens in both directions.

Maple Ridge elementary protest to protect against climate change

Grade 7 Albion students march in front of municipal hall.

VIDEO: Canadian breaks women’s world record for longest plank

Dana Glowacka, of Montreal, held a plank for four hours and 20 minutes

‘I think he’s still alive’: B.C. mom pleads for help finding son last seen a month ago

Family offering $5,000 reward for information leading to the safe return of Tim Delahaye

New poll suggests one-third don’t want politicians to wear religious symbols

Local politicians shouldn’t be allowed to wear hijabs, crucifixes or turbans on the job, survey suggests

Raptors fans far from home adjust plans to watch pivotal playoff game

Raptors currently lead the playoff series 3-2, and a win Saturday would vault them into NBA finals

PHOTOS: First responders in Fernie rescue baby owl who fell from nest

The baby owl’s inability to fly back to its nest prompted a rescue by first responders

Five takeaways from the Court of Appeal ruling on B.C.’s pipeline law

It’s unclear how many tools are left in B.C.’s toolbox to fight the project

Burnaby facility to dispose of 1,500 tonnes of Canada’s trash from Philippines

All 103 containers will be disposed of properly within Canada before the end of the summer

Scheer says it would take Conservatives five years to balance budget

Scheeraccused the Liberal government of spending $79.5 billion of previously unbudgeted funds

Man wants guilty plea revoked in 2012 collision in Abbotsford that killed Chilliwack woman

Michael Larocque was charged in relation to crash that killed Eileen Kleinfelder

Most Read