Greenwalled

For several years now property managers, researchers, and environmentalists have been struggling to develop workable green walls. Most of the ones I have seen pictures of or visited have been of the "ragged" or bushy style, with the vertical plant walls containing a variety of plants densely packed into the vertical frame.

The photo above is the new plant wall in Minto Place. You can see the east wall of the Minto Place Hotel through the skylight above. This greenwall is much more formal than any I have seen before. Philodendrium type plants predominate. I could not identify any blooming plants (eg orchids) or spider plants or asperagus ferns here; these are common in other walls.

I look forward to revisiting this plantwall in the coming months and years to see how it grows and how formal Minto manges to keep it.

Greenroof on Gloucester Street

Two blocky apartment towers, one belonging to City Living and the other CCOC share a common podium made up of a city parking garage with entrances on opposite streets.

It's hard to tell from the ground how well the greenspace is doing on the roof of the tower(s) but the trees on the parking garage roof terrace that joins the two towers is obviously thriving. With no south exposure, and a difficult above ground location, this demonstrates that green roofs can thrive in difficult urban environments.

Greenroofs - CWM

The bottom photo shows the lower roof of the Cdn War Museum green roof. The grass is green. Further up the slope, beyond the admin offices with the gorgeous views of the River, the green roof is decidedly brown.

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There is a N/S bicycle and foot path up the centre point of the museum which takes you to the roof and down the other side. The views are interesting. The path is supposedly open whenever the museum is open (there is a locked gate other times) but I often see it locked mid-day. If you are lucky and see it open, ride up and enjoy the view and unique windblown grass roofscape.

Somerset-Percy Green Roof

This is the back room roof of a house that faces Somerset St, as seen from Percy street. I love the green roof plantings, the ecological clothes dryer, the cozy spot tucked away from the commercial frontages.

WEP Green Roof

The World Exchange Plaza has some delightful garden space. It is hard to believe this attractive patch of green is downtown at Queen/Metcalfe, and is on the roof of the parking garage, and available for anyone to enjoy.

Small Lot Water Retention

1.gravel fill


2.vegetation coverage

3. front yard hosta on red stone mulch

4.pea stone driveway

5.permeable pavement patio

6.ye old water barrel

7.gravel drip line along garage


I think it is possible to retain almost all of the water that lands on a lot. The biggest benefits come easiest: reduce impermeable paved areas, provide soft areas to absorb rain, store rain on site.

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The above photos all come from my 29x100 downtown lot. The lot line is less than 2 feet from the city sidewalk. Photo one shows a retaining wall under the fence at the back lot line, with 3' of gravel fill in front of it for sharp drainage down into the subsoil. The flagstone path and ground cover let moisture sink in quickly.

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I have no lawn, only garden plants. Stepping stones provide access, so the soil never compacts. While grass is OK as an absorbant surface, I prefer perennial plants. If they dont thrive, they dont survive.

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My little front yard is 100% planted, and there is a permeable pavement walk to the porch. All the rain from the second floor verandah runs onto the first floor verandah and then into the red stone front garden with its hostas and ferns and japanese lilac tree. This system absorbs 100% of the rain from the verandah roofs and what falls on the garden, including snow melt.

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My driveway - picture #4 - is made of 10" of peastone laid 20 years ago. As fast as it gets rained on, it drains down into the earth. Once a year I loosen the stone with a fork and pick out the grass or other weeds that have moved in.

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My patio is made of permeable paving blocks. The joints are quite wide, filled with sand. The whole thing is on a sand bed on top of a gravel base. It is new, and I was anxious to see if I had graded it enough for run off, so twice I have gone out in the midst of those heavy downpours to check on the water. Amazingly, it just runs down into the earth, between the stones. There was no running stream of water downslope to the driveway. BTW, the rubble-stone basement is dry.

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I have a single water barrel that fills up very quickly when it rains. I hope to link two more together to retain more water, because I am cheap and that will cut my water and sewer bills. Overflow runs onto another patio, which sometimes puddles in the rain, but it drains down within a half hour or so. None of this water runs overland onto adjacent properties. I have evestrough on one side of my pitched roof, which drains to the flat roof, which drains to the water barrel and patio. The other side of the house pitched roof drips onto my neighbours paved driveway and runs onto his back lawn. Between the pitched roof and the flat roofs, I capture about 60-75% of the roof rain. The flat roofs are slightly concave, and puddle about two inches deep, and drain off slowly after it stops raining, so I can keep 100% of light rains and a bit of heavy rains.

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My neighbors garage is shown in picture 7. It is on the lot line. I put recycled red stones (a curbside find) along the garage with landscape fabric under it to control weeds. I take all the rain that lands on the slope that comes towards me and direct it into my periwinkle and lilly beds.

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For my flat roofs on the back addition, I have been researching green roof systems suitable for residential installations. I will shortly be building a few shallow boxes/trays for sedums, which I will pop up onto the flat roof to green it and experiment to see if they will retain enough water to survive, since I certainly wont be watering there.

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If I can retain a very high percentage of rainfall on my small lot, it should be a lot easier to retain it on larger and suburban lots (lower ratio of building+driveway to vegetated area). Of course, there are other variables, such as subsoil conditions, what is upslope or downslope, and the amount of care the property owner is willing to put in. But the very basics - reducing impermeable surfaces, storing roof runoff, having permeable landscaping - do not require special skills or knowledge and could easily be the "norm" for builders and homeowners alike.

Landscaping resumes at Claridge's Condo

I figured that Claridge might never landscape its project on LeBreton Flats. But in the last few weeks, a lot has happened. Sod appeared on the west side of Lett Street (right side of picture 2) in front of the Beirut-style bomb crater. And on Friday, some rather large trees appeared in the front lawn of the building, along the sidewalk. Compare the size of the new trees to the ones planted a few months ago along the north side of the building, shown on the left in picture 2.

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Picture 1 is of the rear yard, or courtyard between the current building and next phase just starting. Landscapers have been installing decorative paving designed to turn a plain lawn into a sort of sculpture. Three large trees have been planted too. All the area in picture 1 is on the roof of the parking structure. I have not been able to see if they have started the green roof on the seventh floor planters.

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The building has no name, but this week it sprouted a number: 200 Lett Street. Lett is still a private street, as is Fleet, both of which will be assumed by the City as public streets when the development conditions are fully met.

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Behind the building, red-tiped stakes mark out the continuation of the short NCC bike path that will someday run along the tailrace / aquaduct.

Green Roof - Queen Elizabeth Towers

There are green roofs over the parking garage on the north side of the building (shown) and the south side. Both are about 3-5 floors above street grade. The green roof certainly improves the view from the condos. This particular roof does not seem to have pedestrian amenities - no flowers, benches, minimal paths. I wonder if it gets any use, or is mainly for the viewing pleasure of the above units. Note also the benefit received by the Kevlee tower further to the west, which overlooks the roof.

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View is from two thirds the way up the building.

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It is just possible to see a bit of the green roof on the south side of the Kevlee tower at the top left of the photo.

Holland Cross Green Roof

Holland Cross is a mixed use project located at the corner of Holland and Scott Streets. It dates back to the 1980s. There are two office towers nearest Scott, with a not-thriving commercial mall at ground level. There are two residential towers set further south. They share a common parking podium. Two more residential towers were designed but not built on the east side of the common; eventually the land was sold to Domicile which built townhouses instead. Unfortunately, they do not relate in any way to the green roof and do not complete the formal arrangement of structures.

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It is one of my favorite green roofs. It dates from the same era as the Rideau Centre, and may be the product of the same landscape architects, as there are numerous similarities. I love the thick plantings, undulating grass lawns, the allee of trees that celebrates the roof level access from the residential towers.

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It is marked as private property, but there are no apparent restrictions on access, so anyone can cycle or walk into the garden from the commercial podium area between the office and the residential towers. Unlike the Rideau Centre which has generous paved areas, the paths here are narrow and intimate, the emphasis is on the lush landscape. Well worth a visit if you are in the neighborhood.

Another Green Roof

Another in my occasional series on Green Roofs in Ottawa.

This roof is behind a seniors complex on Somerset St, opposite Hartman's. The roof runs through to Cooper St and is above the Centretown Community Health Centre.

I do not know if the allotments and planters are associated with the seniors building or the Health Centre. Whichever, its a bright spot of green on rooftop.

This view from the 16th floor of the Hudson condo building. There was also an excellent view of the brick paved driveways of the townhouses built on Cooper at Kent. The bricks are laid in an interesting circular pattern that apparent from high up elsewhere but not so apparent at ground level.

Claridge's Brown-Green Roof

mid-May

mid-June

Claridge is the developer of phase one, LeBreton Flats. They have half of the first building on Lett Street is constructed and many suites are occupied. The NCC landscaped the area to the north of the building, running up to the new Wellington Street, with paved bicycle path, benches, garbage cans, trees, shrubs, and grass. The did a significant chunk of this work in mid-winter.

Claridge is responsible for doing the landscaping immediately behind the current condo building. The top picture shows truckloads of sand put on the gravel on top of the parking garage roof. They did this in mid-May. One might be forgiven in expecting the green roof of this LEED development to be in place by now. But picture two shows the site as it is today - the only work done is to spread the sand with a tractor. No plants, no grass, no sign of the artistic landscaping consisting of artwork-like paving strips laid through the velvet lawn. And on the roof, where there are several planters so the building could boast a green roof to absorb run off and reduce urban heat effect ... well, nothing green up there yet that I can see.

What must those people who paid a premium on their units to look onto greenroofs be thinking? (Would it be printable?). And to think the developer still has units in the finished building for sale ("immediate occupancy" - with view of dustbowl at the back and Beirut-style crators at the front...) and many units in the second of the building - yet to be constructed - remain unsold. And in early July, tens of thousands of Ottawans will be swarming around the site for Bluesfest. Most developers would see this as a marvelous sales and awareness-raising opportunity.

LEED? More like a LEAD development.

But Claridge is present on the site - they appear to be preparing the hole for the second half of the building, also a 6 floor podium building in yellow brick with another 7 storey yellow brick tower on top.

Green Roofs - Gone? The Rideau Centre

congress centre demolished


Rideau Ctr rooftop path and patio

narrower rooftop path

In this blog's series on rooftop greenspaces I've tried to illustrate that we already have a number of attractively landscaped and useful green roofs. One of the earlier roofscaping treatments was the Rideau Centre, and it's one of the largest. It's a maze of wide and narrow paths, trees, shrubs, lawns, patios. Not many benches though, probably to discourage loitering or using the park. Regular inhabitants include Rideau Centre staffers smoking or lunching, bunny rabbits, squirrels, birds, and transients. Main access points are from the doors at the Cinema level (4th floor) or staircase up on the MacKenzie King Bridge just west of the main entrance.

A portion of the landscaped roofs was over the former Congress Centre, now mostly demolished. The new building will have extensive glass roofs, which are the antithesis of green roofs: they shed all their water, fast, and do not provide useful recreational space or support a habitat.

As always, you can click on the photos to enlarge. I highly recommend doing just that on these photos : the size and vigor of these trees and shrubs is truly amazing.

I vaguely recall that whent the Rideau Centre was built, provision was made for several high rises (offices and residential) to be built above the complex, which would have vitalized the mall at all hours and given more people a proximate enjoyment of the lush rooftop.

Green Roof - Bronson Place

The roof of the parking garage at Bronson Place has lots of greenery planted, including some thriving trees. The roof includes an indoor pool area and an outdoor totlot with soft floor.

Greenroof Example - Pl de Ville

One of Ottawa's older multipurpose developments has a lovely green roof on its south side. This roof is above what was for 30 or so years a shopping mall, but for the last years has been federal government office space. The pond adds an unexpected water element to the downtown, as does the fairly large bright green lawn. It is highly visible, located adjacent to one of the busiest downtown transitway stops at Place de Ville. The glass pyramid lets light into the office area below. It suggests the pyramid glass structure at the Louvre in Paris, but on a way smaller scale. It does not figure in any Dan Brown novels, yet.

More Green Roofs in Ottawa

There is a very nice and useful green roof at Preston Square, 333 Preston Street in the heart of Little Italy. It is bordered by the two taller office towers (Xerox and Adobe towers) and the low rise office building (Ontario services) and the mid-rise apartment building. All buildings open out on the roofscape, with paths, benches, deep planters, lawns, etc. It is well kept and accessible to the public. Below the roof are parking areas, shipping and receiving areas, etc.

I especially like this green roof for its accessibility and utility to a variety of office and residential users.

LeBreton Landscaping adventures continue

NCC plantings along new bike path, view from Wellington



Claridge doing nothing yet... this is their green roof



NCC plants up to edge of Claridge condo




NCC trees along north edge of condo

In a posting in March, there were photos of the NCC doing winter landscaping on the Flats. They filled in the depression on the north side of the Claridge condo on Lett St, phase 1 of LeBreton Flats north of Albert. They graded the land to a lawn area, roughed in bike/pedestrian paths, and installed a generous trench of topsoil for a row of trees along Wellington. They are now planting in the new areas.

Note that the new bike path goes nowhere. It descends downslope from Wellington, along the west side of the tailrace landscaping. Once it reaches the Claridge zone, it stops dead. Claridge is supposed to continue the path and install landscaping along the public lands between its building and the ravine, as part of its subdivision agreement with the city. There is no sign of Claridge crews. Once they build their section of bike path, it still won't go anywhere until Claridge builds tower 2 of the current building. There is also no sign of Claridge installing its green roof on the parking garage or in the roof top planters.

All this is in marked contrast to the lot to the immediate west of the Claridge condos. It remains a hole that is more evocative of Khandahar than Ottawa. Anyone want to spend half a million buying a condo with a view of an open pit?

Green Roofs in Ottawa

War Museum

This photo shows the west side of the War Museum roof. This roof is unusual in that it is at ground level at the west edge and slopes up to be an elevated roof. Another section of roof is beyond the office space structure. It is accessed from a north/south ramp and path system that crosses the building at midpoint. Originally designed to "break" the very long narrow building into two, it "completes" the north / south pedestrian circulation scheme on the Flats, should it ever be developed. Two years ago this path was usually open. Now, whenever I go by, it is blocked off by a locked gate.

This green roof was chosen by the architects primarily for its symbolic role, exemplifying the regreening of battlefields. It is not really visible from the front, back, or east end of the museum. Probably the upper floor future condo owners along Wellington will have the main view.

Green Roof examples

Minto Place podium

With this picture, showing the green roof on the podium level of Minto Place, I intend to start a series of photos of existing green roofs in Ottawa. There are over a dozen green roofs I can think of immediately. Most are at the podium or near ground level, where they have a useful aesthetic function.

I took this from the elevator lobby of Minto Place hotel, about the 8th floor. This window also had an oblique view of the similar roof garden on Constitution Square.

While I think green roofs have a function, they are somewhat a solution in search of a problem. If we want to green our city, I think we should make a list of priorities based on a comparison of benefits. I suspect greening parking lots and walls would have a much higher payback than green roofs, especially ones high up on buildings where there is little aesthetic benefit. Lower level roofs have a higher aesthetic payback, are more amenable to supporting wildlife, and offer the same or better rain fall runoff and air cleaning benefits, compared to higher roofs.

Green Roofs in Ottawa

A view of Minto Place podium green roof, this one showing an area with public access. The three tepee skylights are over the pool over the Hasty Market; the larger skylight on the right is over the main lobby/concourse. A similar green roof is barely visible in the background on Constitution Square. Access to the roof is from the slightly larger tepee skylight which houses a stair up from the pool deck.

I think it is interesting to note how much of the green roof is actually decking and other "not so green" features.

More on Roofs, greening, homeowners

Chris asked me if I had considered a white roof. Yes, I did. But first, consider that there are two subjects here: one is replacing the existing roof covering when it is past its prime, the other is adding something like plant sedums in trays on top of the existing flat roof.

The 100,000 sq ft warehouse I view from my 3rd floor windows was redone two years ago in white. Very reflective. I know white shingles on a sloped roof have a drastically shorter life than black shingles, I dont know if a white flat roof is any shorter lived. If I have to redo my flat roof (coming up in the next year or two, or so I have been saying for a few years ....) I will certainly do it in white or green (better to look at). However, sedum in shallow pots has way more benefits ... its very cooling, its green, absorbs rainfall, and it shades the tar roof itself and effectively doubles or triples its life because sun exposure is the principle cause of roof deterioration.

I am also getting an evaluation of my roofs done for PV solar, unfortunately the best sloped roof already has a big dormer on it and a bank of six skylights, thus reducing the area available to put roof PV up; but I could also put them on the flat roof, even though it has a less ideal exposure (SE rather than SW) but it would be best to redo the flat roof at the same time which adds about 7k to the cost.

The roof is well able to carry the weight of the sedum trays etc as they weigh less than winter snow, so IF i took them all down each fall and laid them on the patio, the roof will hold the snow weight, but will it hold both the sedum and the snow if I leave the sedum up there? Unknown; and high risk too! Plus there is the logistics of putting up and down the trays twice a year.

The base of the municipal water runoff problem is that businesses or homeowners that increase runoff pay the same water /sewer charges as do firms that moderate the flow, like MEC or IKEA, ie there is no reward for the virtuous or punishment (cost) to the extravagant. So, Council should tinker with the pricing mechanism of sewers, not go imposing a green roof "solution" onto those classes of payers they feel are the least able to notice or object to being victimized by a discriminatory tax.

Regardless of municipal policies, my green roof interests are motivated both by environmental concern and my pocketbook: trade off the cost vs the benefits.