From CLT Panels to Home in Five Days

November 09, 2020

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Stich Consulting & Design was founded in 2013 by Tomaz and Jasminka Stich to promote the construction of Passive House buildings. Tomaz—a carpenter, engineer, and certified Passive House Designer—runs the consulting and design business, educating engineers, architects, and carpenters about the benefits of Passive House and renewable energy. The company is a representative for several European Passive House-quality manufacturers in Canada and also offers Passive House courses and exams a couple of times per year.

Now the company founders can speak with extra authority on the benefits of Passive House. Tomaz and Jasminka just completed their own Passive House in Invermere, British Columbia, built using prefabricated cross laminated timber (CLT) panels imported from Europe. The building was recently certified as meeting the Passive House Plus standard. Here Tomaz discusses the process of building their home:

Our focus has never been only on Passive House but also on renewable, wood-based products. As we were very familiar with the cradle-to-grave sustainability and high quality of the products manufactured by the suppliers we work with from Austria, Germany, and Slovenia, we naturally chose to work with them. We decided to have our envelope components prefabricated to the greatest extent possible—about 90%—instead of shipping every material separately as we had done in the past, pushing the limits more than usual in order to prove that to do so was not only possible, but cost effective.

Two truckloads of wood-fiber board were delivered from Germany to Slovenia to be used as our insulation and soundproofing material. Our triple-pane, PHI-certified aluminum-clad wood windows and all the CLT panels came from Austria. All of these materials were assembled in Slovenia by Lamo, a carpenter and client from earlier days when we used to live in Europe.

The prefabricated wall panels include 12 inches of wood-fiber board insulation attached to the CLT panels and built-in windows, with the strapping and siding attached as well. Each wall was basically one panel. All wall, floor, and roof panels were loaded and shipped in four 40-foot open-top containers to Invermere. Assembly of the house was done straight out of the containers by crane and took five days to lock up.

After we finished the roof insulation and roofing, which took a bit longer than anticipated due to climate conditions in the Rocky Mountains, the interior was finished. The finished CLT walls, ceiling, and roof were left exposed. Oak flooring throughout the house was chosen, consistent with our goal of using exclusively natural renewable building products. A 4,000-liter rainwater-harvesting tank was added for flushing toilets and gardening.

Two panels of vacuum tubes (for a total of 60 tubes) installed on the roof will take care of domestic hot water generation year-round. An ERV supplies the ventilation; its supply air is fed through a 100-foot geothermal loop (earth tube) to preheat the air in winter and precool it in summer. This summer on a very hot day the loop was able to cool down the incoming air by 20°C (36°F), which means basically free air-conditioning 24/7. Exterior motorized venetian blinds on all the south-facing floor-to-ceiling windows are used to prevent the building from overheating.

The goal with this high level of prefabrication was to show that it’s possible to build a high-performance Passive House with its predictably high level of comfort for the same price—or even less—than standard houses built to code by cutting down on expensive site labor. The cost of the house was roughly $210 (Canadian dollars) per square foot, and that includes the shipping of the containers.

—Tomaz and Jasminka Stich

Stich Consulting & Design represents the following companies in Canada: Schneider Holz (wood-fiber board, CLT, and glulam); Optiwin (windows and doors); and M‑Sora (windows and doors).

Box: Thermal Envelope

Exterior wall

CLT (Exposed inside) 120 mm
Wood Fiber Board (WFB) 200 mm
WFB T&G 100 mm
Strapping 40 mm
Wood Siding T&G 25 mm
U‑value = 0.119 W/(m2K)

Basement floor / floor slab

Oak Flooring 19 mm
WFB 13 mm
Plywood 19 mm
Strapping 45 mm
Concrete (reinforced) 152 mm
6 mil Poly 0.6 mm
EPS 152 mm

Gravel Compacted 100 mm
U‑value = 0.097 W/(m2K)

Roof

CLT (exposed inside) 140 mm
WFB 240 mm
WFB T&G 120 mm
DO 180 membrane
Strapping 38 mm
Cross Strapping 38 mm
Metal Roofing
U‑value = 0.101 W/(m2K)

Windows/ Frame

Wood Aluminum Clad windows with motorized exterior venetian blinds
U w‑value = 0.63 W/(m2K)

Window/ Glazing

4 EN Plus/18/4/18/4 EN Plus
Edge compound Superspacer black
U g‑value = 0.5 W/(m2K)
g ‑value = 52 %

Entrance door

U d‑value = 0.54 W/(m2K)

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