CASE STUDIES

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#1 Leppanen Residence
#2 Miller Hall Remodel
#3 Lightcatcher Museum
#4 Creekside Building
#5 Park Place Condos
#6 Throw-n-Grow

#7 Green Walls Are Cool, Too
#8 Garfinkle Residence
#9 Frazier Office Studio
#10 Hartrich Residence
#11 Coops, Sheds, and D.I.Y.
#12 Lincoln Square

Case Study #1 — Leppanen residence

View of the green roof from the Leppanen’s living room

The 750 square-foot Leppanen green roof was installed in 2005 and was inspired by a conundrum: If they built their desired shop/garage addition, did they really want the primary view from their living room and kitchen windows to be a boring rooftop? After applying some brain-power, elbow grease, and nine pages of engineering, the answer ended up being a green roof of their own making.

Contractor:      Mallard Construction (David Leppanen)

Design:           David and Teresa Leppanen

Plants:      25 flats of 4″ pots of groundcover plants: primarily sedum, saxifrage, and sepervivum; 500 bulbs; ornamental grasses; herbs; larger plants in several pots

Plant sources:   Sunbreak Nursery and Wind Poppy Farm and Nursery

Soil mix:          15 yards  —  75% crushed lava,  5% sand, 20 % compost

Soil source:    Stream Organics (now Eco-Soil)

Soil depth:      6 inches (avg.)

Drainage mat:  J-DRain

Waterproofing:  seamless single-sheet EPDM

Roof slope:    3/4″ (depth) per every 12″

Structural:   2/12 dimensional lumber @ 1′ o.c.

Engineering:   Dipple Engineering (primary,) Bourne Engineering, Hadj Design

Quotes:  “I’m so glad we went with at least six inches of soil because it allows you to plant such a wide variety of things.” — David Leppanen

“It is great drinking your coffee here (in the living room) and looking out on it — it changes all the time.” — Teresa Leppanen

Cost:  David Leppanen, owner of Mallard Construction, acted as his own contractor. When considering what he might bid for a similar remodel of a garage addition with an installed green roof, he estimated about $30,000.

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Case Study #2 — Miller Hall remodel

Test bed outside Miller Hall.


The Miller Hall green roof is by far the most complex roofing system that has so far graced these pages. Some of the redundancies and seeming excesses of this roof are surely a result of its institutional setting on the Western Washington University campus. In its defense, the university hasn’t been able to significantly upgrade this building since its initial construction in 1968. This mega-million dollar renovation, however, appears to have created a monument capable of surviving several decades, or apocalypses, into the future.

A nest of girthsome steel I-beams support the roof and will allow the “Student Collaboration Space” below to be cloaked in nearly continuous glass walls. The roof’s layers, as shown in the following graphic, include metal decking, rigid insulation, and multiple layers of waterproof membranes. If you want to stay dry in a sudden rainstorm — or survive a cataclysmic earthquake — this building seems a good place to wait out the unpleasantness.

Another feature that will help ensure this renovation’s staying power is its Leadership in Energy and Environmental Design status. The project, as mandated by the State, is required to get no less than a LEED Silver accreditation. The addition of a naturally insulating and water-filtering green roof, among many other improvements, may help to nudge the project’s LEED status toward Gold.

B.G.R. needs to thank Caroline and Tom, at Dawson Construction, and Matt Allen, at  Snyder Roofing , for helping me document their roughly 3,000 square foot project. Thanks also to the various professors who have allowed me to jam a camera out of their windows.

The waterproofing system is called the “System 1000” and it was designed / manufactured by Sika Sarnafil. The vegetative assembly is from Xeroflor. The green roof installation was done by Enviroscapes Northwest, Inc.

The “System 1000” and vegetated assembly layers are as follows:

–          Metal decking

–          ½” Georgia Pacific Dens Deck / mechanically attached (screws & plates)

–          Sarnafelt NWP Separation Layer / loose laid

–          Sarnafil G476 Waterproofing Membrane / loose laid

–          Sarnafelt NWP Separation Layer / loose laid

–          Sarnafil G445 Protection Layer / loose laid

–          5” Sarnatherm XPS (extruded polystyrene) rigid insulation (R30)/ loose laid

–          Xero Flor XF112 Root Barrier / loose laid

–          Xero Flor XF108H Drain Mat / loose laid

–          Xero Flor XF159 Water Retention Fleece / loose laid

–          2” Xero Flor Xero Terr Growing Media / loose laid

–          Xero Flor XF300 Pre-Cultivated Vegetation Mat / loose laid

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Case Study #3 — Lightcatcher Museum

Installed in 2009, the Lightcatcher’s green roof will provide Bellingham with multiple educational opportunities. Besides being accessible to the public, via an ADA compliant bridge, the roof is also going to undergo occasional monitoring as part of the conditions of an Art of Stormwater Management grant that the roof and building design was awarded.  Bellingham Green Roofs will look forward to seeing the results of these data sets and will certainly share them here as they become published.

Square Feet:  2,700

Public access: Yes, during museum hours.

LEED certification:  Silver

Waterproofing:  single-ply “EverGaurd” TPO, 60 mil, installed by Western Roofing

Soil depth: 4″ in layout, 6″ at borders of mechanical structures (heat/ventilation) to allow for taller plants

Roof systems:  modular flats of pre-planted vegetation from LiveRoof.

Roof design:  Renee LaCroix, with City of Bellingham, collaborated with the nursery division of LiveRoof — Green Feathers Nursery — which, unfortunately, seems to have a very clunky and frustrating Web site at the moment.

Estimated cost: $30,000 – $35,000 for everything installed above the roof decking. (In talking with the architects and site foremen, however, they noted that this un-planned addition to the museum ended up costing considerably, freakishly, more. The structural considerations demanded by construction codes need to be envisioned, first and foremost, as part of your blooming green roof brainstorms!)

Plants:   The following list are all sedum varieties planted on the Lightcatcher’s roof.

sexangulare
sp. Tricolor
sp.Voodoo
stefco
oreganum
rupestre Angelina
album ‘Red Ice’
kamt. Weihenstephaner Gold
Matrona
spe. Neon
c. Lidakense

This photo gallery represents two seasons. The early Autumn photos show the scraggly remains of the sedum’s flowers.

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Case Study #4 — Creekside Building

Currently holding status as the largest green roof north of Seattle, the 6,000 square-foot roof above John Blethen’s Creekside Building required no structural modifications despite being built in 1929. Using abundant help from friends, this DIY install seems to have been a fairly basic — if labor intensive — process. From the original concrete roof decking and waterproofing sealant, the following layers were added:

Insulation:   Two inches of urethane foam, spray-on

Waterproofing:   Spray-on, product unknown

Drainage:  One-inch mat of J-DRain dimple-board (felt backing and root barrier attached)

Soil:  80 yards of green roof mix from Stream Organics (now Eco-Soil)

Plants:  Six flats of sedums from Sunbreak Nursery which were furiously propagated into roughly 6,000 starts (done the previous year in the greenhouse — also atop the roof), random grasses, and a raised-bed vegetable garden.

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Case Study #5 — Park Place condos

Park Place condos, perched above the entrance to Boulevard Park, earned LEED Gold certification in late 2008. Finding information on this roof has been a bit frustrating since the collapse of the housing market. What I can report is that a layer of insulation sits atop the concrete decking, followed by dens-deck sheets and an EPDM membrane. These photos represent roughly one year of growth and were taken right after a binge of brutally hot weather. While not claiming expertise in this realm, it appeared to me that the plants were fairly stressed and that the lack of early maintenance may have handicapped this roof’s chances to get a solid launch.

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Case study #6 — Throw-n-grow

Impatience has its virtues … but so do structural engineers

Mother nature, of course, can also be impatient.

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Case Study #7 — Green Walls are cool, too …

Thanks to Gina Austin, Bellingham Parks Dept. project engineer, for the following information:

This retaining wall uses Criblock™ reinforced concrete stacks available through and installed by Retaining Walls Northwest, Inc. Costs will vary depending on the complexity of the project, but this particular wall ended up costing about $40.00 per square-foot in 2005.

This sedum-infested wall can be found on the interurban Greenway trail, just before it crosses into Arroyo Park.

G-dog ponders why more retaining walls don’t opt for this simple and attractive option. Perhaps the allure of pre-fab stacker “stone” is just too overpowering.

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Case Study #8 — Garfinkle Residence

When Victoria and Steven Garfinkle realized they needed a new roof for their house, they first explored the prospect of adding a green roof to the entire structure. Unfortunately, the steep slope that the Garfinkles live on conspired with the existing framing and foundation of their 1971 home to make the addition of a green roof a practical — if not financial — absurdity. (Unlike some commercial or industrial buildings, whose designs may be over-engineered to handle additional heavy loads up high, residential green roofs can be problematic remodels unless the house has very good “bones” to begin with.)

Undaunted by this setback, the Garfinkles and Gallant Design and Construction found a compromise in the carport area which had easier access to the foundation and was more readily conducive to structural upgrades. The result is a roughly 600 square-foot green roof which dominates the visual impact of the front of the house through the use of both a raised bed in its center and deep enough soil to allow for tall grasses, bushy native ferns, sedges and wild strawberries. By opting to use the same waterproofing membrane on the rest of the roof, Steven Garfinkle said they saved considerably over the cost of using metal which had a similar warranty and life expectancy. The following are some other details of this green roof design, courtesy of David Gallant:

Structural engineering:  David Bradley Engineering

Soil depth: 1 foot

Framing upgrade: 2×12 joists set at 16″ on center, supported by two freakishly stout gluelam beams

Soil source: Pacific Topsoils (Seattle)

Waterproof membrane: 45 mil TPO, installed by Joosten Roofing



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Case Study #9 — Frazier Office Studio

Peter Frazier’s stunning but diminutive green roof was a response to both environmental and aesthetic concerns. Perched on the steep slopes below scenic Chuckanut Drive and above Bellingham Bay and the San Juan Islands, the surrounding landscape offered a strong incentive to not interfere radically with the portrait nature had already perfected.

One priority Frazier had was to blend the 2008 addition of his 10’x12′ detached office with the cosmetic themes of the main house. The house, built in 1967, is essentially a flat-roofed rectangle that appears to have been boldly stabbed into the cliffs. Adding a plain torch-down roof to the new office, however, would present an eyesore to both the views from the house as well as a distraction from the entry path and porches.

“I went with a green roof for aesthetic reasons but also in the hopes that it would be a sort of showcase (for green roofs)” Frazier said. “I really think we should be seeing these roofs everywhere.”

Frazier said that the added labor and structural considerations of the green roof added expense to the project, but he was pleasantly surprised that the materials were not as much as he expected. Using primarily native species — including a moss-covered log harvested off of the property — the roof melds seamlessly with the surrounding flora and provides Frazier with a very simple, yet spectacularly located, work space.

Year built: 2008

Roof size: roughly 180 s/f

Plants: Sedum stonecrop, native ferns, Oregon grape, various opportunists

Structural engineering: David Bradley

Soil depth: 6″ – 9″

Soil: custom mix — pea gravel (two dimensions), sand, topsoil

Framing: 2×6 wall studs, 2×12 joists

Membrane: EPDM

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Case Study #10 — Hartrich Residence

Nick Hartrich, as the green building and smart growth program manager for Sustainable Connections, has been a driving force for various building policy changes at the City of Bellingham and is largely responsible for AMM 303, the city’s new vegetated roof policy. As an ardent fan of green roofs and as an advocate and student of green building practices, Hartrich congealed his various talents and networking resources to create Bellingham’s first sloped green roof assembly. To the many thousands hereabouts who likewise live under sloped roofs, this project represents an especially welcome addition to the case study roster.

Hartrich made every effort to see that his roof was “green” from bottom to top. The use of nearly zero impact pin footings supporting the recycled porch posts and beams, the local companies and consultants used for the project, and the locally purchased soil and sedums — all elements conspired for Hartrich’s master plan. In furthering his promotional efforts for green building, Hartrich also used his roof’s installation as an educational opportunity. During a deliriously rain-free October afternoon, Hartrich and Sustainable Connections threw a roof-raising party and green roof seminar that was well attended by the folks who supplied the roof’s materials and numerous ‘Hamsters angling for ideas for their own projects. With about one-third of the largely pumice soil already waiting atop the waterproof membrane, a dervish of buckets and flying sedum tiles saw the roof mutate, in less than 34 minutes, to a finished green roof.

One of Hartrich’s goals for this roof was that it serve as a pilot project and real-world example of what is now possible by buying locally and using the city’s new permit standards. Kim Weil, from the COB planning department, explained at the seminar how green roof projects such as this could see incentives from the city ranging from the halving of permit fees, to — for the larger projects — eliminating the need to install detention ponds.

Roof Size: roughly 200 square feet

Soil depth: 4 inches

Soil mix: 3 yds. of a proprietary mix designed, sourced and mixed locally by Sweeney Horticultural Services

Plants: “Color Max” sedum tiles from Etera, with future (native specie) accents added from Plantas Nativa and Sunbreak Nursery

Horticulturist: John Sweeney

Engineering: David Bradley Engineering

Framing: recycled timbers from Duluth Timber Company, installed by Bellingham Bay Builders

Membrane: 50 mil PVC from Duro-Last, installed by Esary Roofing

(It is worth noting that no drainage mat was installed in this roof — Hartrich and his consultants are banking on the high permeability of the soil mix and the slope of the roof’s pitch to scurry the water to its drains. A root cloth was installed on top of the membrane to protect it from abrasion and to reduce soil slippage until the sedums establish their rooty bits.)

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Case Study #11 — Coops, Sheds, and D.I.Y.

Mark Wickman originally built this shed for garden tools when he lived in the Sunnyland neighborhood. Now that both the shed and Wickman have moved to Fairhaven, the interior has been remodeled to serve as a quiet, cool, summer cottage or as a spare bunk to house occasional overnight visitors. Using pea-gravel for a drainage matrix, and using a 4-way soil mix with extra compost added in, made this greenroof surprisingly heavy — the movers estimated the shed at 12,000 lbs. and Wickman said they wrestled mightily to keep their equipment from getting damaged. The roof, however, seems none-the-worse for its travels and the somewhat unconventional soil mix is clearly supporting a healthy population of grasses, sedums, and flowers.

Built in 2006 and using primarily salvaged materials purchased from the ReStore, Wickman estimated that he spent no more than $4,000 on this project. The soil and drainage layers are roughly 4-6 inches, the waterproof membrane is PVC, and the drainage is accommodated by a stout expanded metal mesh at the perimeters which, according to Wickman, does not deter the rainbarrel he has attached to a downspout from filling up occasionally. The framing is robust; 6×6 posts support 4×6 rafters beams. Wickman slightly altered the plans he gathered from internet searches since he wanted to meet the City of Bellingham code for detached sheds — thus the dramatic gables on a fairly small building footprint. His designs were further assisted by a seminar held by Patrick Carey and Hadj Design.


Shannon Maris, LEED AP and owner of Light Source Residential Design, has been working on a highly visible roof in the space that formerly housed the Fairhaven Rose Garden. As you turn left onto Chuckanut Drive from the 12th St. Bridge this roof is part of the showcase for what will eventually become the Center for Local Self Reliance. Maris sent me an e-mail with the following update, so I’ll just let her describe the roof and provide updates below, in the photo gallery, as this project matures.

“We did the budget version of a vegetated roof,” Maris wrote…

“Not a lot of details other than to use screws to hold down the plywood. Use hi-grade plywood without the donut hole patches (sharp edges), we adhered the pond liner with Resource Conservation Technologies EPDM adhesive, pond liner from Koi Ponds up by Lake Padden, we used Mira-Drain foundation drain for the drainage layer, decided to put the plants in nursery trays for ease of moving (if needed) and pathways for when weeding is needed (we would use deeper ones next time), soil came from SunBreak Nursery an 80 inorganic/20 fir bark mix. Flashing for 2×6 raised edge still to come, as well as rain barrel hook ups

“This is an experiment over a tool shed on a tight budget… I would not do this type on a regular house roof.

“Plant material was grown from cuttings and starts donated by a nursery in Mt. Vernon, Cascade Cuts, and John Blethen’s green roof (see Case Study #4 –“Creekside Building”). The cuttings took about 3 weeks to root.”

Thanks Shannon! We’ll look forward to watching this green roof experiment, and the rest of the Center for Local Self Reliance, come into bloom.



Bill Beach bashed out a derelict tennis court on his property to allow for a riotously successful garden space and this chicken coop/storage shed/goat pen. Located on 37th St. as the road winds up toward Lake Padden, this is another highly visible addition to Bellingham’s growing green roof population. Beach finished this project in 2011 and, being a victim of many self-inflicted restoration projects, tried to use as many recycled or ReStore materials as possible. Besides having some very nice architectural accents, the interior cladding appears to be Redwood — a ReStore find that Beach couldn’t walk away from despite being a tad exotic for tool storage. As for adding the green roof, Beach said he liked the aesthetic and wanted to give it a try. “Since I was doing the work myself it didn’t seem like it would be too much more expensive,” Beach said. “It makes me feel better about building luxury condos for chickens.”

Beach reinforced the 2×4 roof rafters, set at 2′ on-center, with HC-35 Simpson fasteners and followed other suggestions for strengthening the roof from sources found in on-line plans. Using tar-paper to shield against splinters that might weasel up from the 5/8 plywood, Beach found an EPDM pond liner at Lowes which covered the 120 square-foot roof. At the gable ends, where a gutter would normally live, Beach then chose to apply wire mesh and a synthetic-weave root clothe to allow for drainage and to keep the soil from eroding off the gentle slope.

Although the plants are new and have yet to fully establish, they so far appear happy in their new home and have taken to the 4-way soil mix and pea-gravel drainage layer that Beach purchased from GrowSource. His selection of some standing sedums (a larger variety than the typical groundcovers) and use of California Poppies are somewhat unusual for green roofs around here. As with all green roofs, however, Beach’s experimentation might be a $5-$10 hiccup or it could show the way for the rest of us as more roofs, and more plant species, are tested in this region.

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Case Study #12 — Lincoln Square


It was nice to see council man Jack Weiss (above) and mayor Dan Pike present at the grand unveiling of Bellingham’s newest and largest green roof installation. Hopefully, as has been proven in cities around the world, the active interest and support of local politicians and planners will help us to see even more green roof projects gracing our gray city landscapes!

The massive retrofit of the formerly aging, inefficient, and somewhat bleak Lincoln Square complex was the result of very hard work from Todd Nelson, the development manager for Bellingham/Whatcom Housing Authority, and the grant writers on his staff. Due to their efforts, the 397 residents of Lincoln Square will have vastly improved living conditions and the taxpayers, who support the cost of running and maintaining such HUD facilities, will save scads of money on energy and water bills. While green roofs are my priority and fixation, I encourage you to visit the BWHA Web site, here, to learn more about the long list of green upgrades and innovations this $10 million project offers to this community.

The three green roofs at Lincoln Square cover 6,200 square feet of the facility’s first floor annexes and covered walkways. Although there are other green roofs in town that can accommodate a few visitors on top of them, Lincoln Square is the first to install a truly intensive green roof. The courtyard, in the above photo, provides many of the same water filtering and retention properties (along with the typical list of 20 or-so other benefits of green roofs) while also being a great place for the residents and their visitors to relax and gather. This particular roof sits atop the maintenance shed for BWHA and, being a heated facility, the insulating effect of this upgrade — as with any single-floor addition of a green roof — should deliver considerably reduced power bills.

The intensive roofs at Lincoln Square, as is typical with most any newly installed and immature green roof, do not yet make for a stunning photo essay. For that reason, and being a victim of some rather sordid lighting during the September unveiling date, I plan to return to this site and give it a proper grilling in the future. (Besides, and in addition to that sniveling, I am eager to see the contractors finish the green wall installation!)

Lead contractor:  Dawson Construction

Green roof installation:  HyTech Roofing

Membranes:  Carlisle EPDM (90 mil. for the intensive roof, 75 mil. for the extensives)

Plants: Etera roofing tiles comprised the bulk of the planting (4,000 square feet!)

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7 Responses to “CASE STUDIES”


  • Wow! These are great. I love the view of the green roof from the Lepannen’s living room -very cool and more affordable than I would have thought.

  • The “Stream Organics Management, Surrey, Canada” link is dead and I cannot find it from a Google search. do you have other media sources?

    Thanks

  • Thanks Craig — From what I can tell Stream Organics is now Eco Soil Recycling Corp.. I’m awaiting contact with a human being to confirm that they can offer the same services that previously supplied soil to Bellingham roofs in the past. In the meantime you might try Pacific Topsoils, which, I understand, has a branch site somewhere near Marysville.

  • It was our pleasure to provide Nick with our SEDUM TILE®. What a great demonstration of a green roof installation, many hands on people attended and it was great fun to visit with all!

  • Sweet can i grow weed on mine.

  • Technically, yes. Given enough soil and probably a frightful irrigation regime, your “herb garden” would flourish. In the northwest, however, adaptive species — those that can tolerate drought and a rooftop environment — are generally preferred and are more in line with the philosophy of low-impact development and energy conservation that green roofers gravitate toward. Good luck with your project!

  • To Debra: I’m looking forward to visiting Etera and rolling around on acres of sedums! The thing I love most about Hartrich’s roof is that it is VISIBLE — it will be a long-standing advertisement for green roofs in this town and will doubtless inspire many similar projects. I’ll send you the photos when I’m a bit more organized.

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