Day 2 at Building Science Summer Camp

Pierre Busque is an engineer with Levelton in Vancouver, British Columbia. He has over 20 years of experience in one of the most miserable places in the world to build in, but it's also one of the most attractive places to live in—the building-science version of beauty and the beast. He will regale us with stories of metal roofing in Whistler, curtainwalls and the Qube, historic buildings, recladding of schools in Sayward, and a few lawsuits. He has so many images of building porn that he is on a most watched list. The second most important thing to know about Busque is that he is a talented guitarist—the band is in for a treat.

Vancouver has had its share of water problems. The rotting condo catastrophe is the most famous, but there have been water problems in the area for a long time. One reason, according to Busque, is that there is tremendous variation in the amount and distribution of rainfall among towns in the area: from desert to rain forest and from slow and steady rain to sideways gully-washers. But weather variation isn’t a problem if designers (architects and engineers) don’t try to impose their hometown’s weather patterns on a different city.

When designers from occasional gully-washer cities underestimate the power of constant light rain, they can do as much damage as a designer from the desert underestimating a gully-washer. Busque: “Small leaks over a long period of time will really cause your building to go to crap.” Big leaks followed by long dry spells are easier to overcome than little leaks that can never dry out.

There are four basic causes of building failure:

• Ignorance
• Carelessness
• Negligence
• Greed

Ignorance, according to Busque, is the only one we can do anything about. Designers need to look at local solutions, talk to local experts, and don’t forget to talk to old trade contractors. Busque showed us a sill-pan flashing design that a roofer showed him—without cutting the metal (stay tuned, I’ll make a short video using paper as a model). “They don’t build them like they used to—well, buildings leaked 100 years ago too, but the real pigs were torn down.” The good ones have remained. The guys that built the good ones know how to shed water.

Busque also offered four rules about windows:

• Treat all windows like they are leakers, because they really are.
• Storefront windows should only be used under cover (this includes residential).
• Because all windows leak, a sub-sill membrane with upturned edge is necessary
• Never fasten a window through the sill. Even if the manufacturer demands it. If you must break this rule, elevate the membrane at the fastener with a shim to direct water away when it leaks through the hole (this tip from Ray Moore in the audience).

A liquid membrane that Busque likes is called Siplast, a PMMA membrane (polymethyl methacrylate).

—Dan Morrison is managing editor of GreenBuildingAdvisor.com.