Proper Application Methods
It Looks Wrong
The year was 1994: I just arrived in Vancouver, British Columbia, and was discovering the differences between the United States and Canada. On my whirlwind tour of the city, it was apparent that stucco was more popular than I thought in the Great North. Even old buildings had stucco on them. I discovered differences in construction and different terms to describe items. The Canadians called our MarbleCrete finish a “rock or slop” dash, called rain gutters “eavestroughs” and the use of soap was a common practice in cement plaster.
I was quickly introduced to the leaky condo crisis that had recently gripped Vancouver. Groups like the Canadian Housing and Mortgage Corp. were frantically trying to discover why there was a sudden rash of leaky buildings throughout the city. I sat in a symposium and heard one expert claim to know what the problem was. He held a picture of a more traditional stucco home. He emphatically stated, “This is the problem.” I clearly remember being perplexed and curious what he would say next. He went on to explain that particular style of house was fine for the southwestern United States but not appropriate for climate in that region. At that time, I had no idea if he was correct or not. The presenter then focused on his three prime issues for the recent rash of leaky buildings:
- Smaller overhangs
- Flush mounted windows
- Use of stucco
I then went out to several projects in Vancouver to see for myself. The differences I noted were no weep screeds, only one layer of 30-minute building paper and reverse lapped window flashings were routine. I was certain these issues—the last one in particular—had the greatest impact on why the new buildings were leaking.
My Soap Box
I was excited to give my first presentation on my revelations as to why new construction leaked. I even commissioned a mock-up to illustrate the proper way to flash a nail flange window and integrate it with building paper. I left a printed instruction sheet from the Stucco Manufacturers Association complete with illustrations. To my surprise, I came back the next day to find the mock up was the same as I had seen as common practice on local projects, namely the reverse laps. I asked the installer why he did not follow the illustrations.
He was fully aware it was in contradiction to the diagrams. He was certain the drawings were a mistake, as it was not how he had been taught. I took the step of applying water to his mock up and demonstrated that the reverse laps directed the water into the wall cavity. He then vowed to change and to follow the presented diagram. The next day, I returned and the wall appeared unchanged. I was certain we understood each other. He clarified, “I did it your way.” He pulled a top piece of paper off the wall that hid the proper procedure. I asked, “Why did you add that piece of paper?”
He said seeing it that way just looked wrong to him, he had to cover it. Unfortunately, things did not get better at the actual symposium. While my Canadian audience was very polite, they were pretty adamant I was wrong in my assessment of why new buildings leaked. The problem was clearly the small overhangs, setting windows flush and using stucco, not poor flashing.
The Canadian Housing and Mortgage Corp. and city of Vancouver were under tremendous pressure to do something. They needed to show action; the panacea began to change the way we put on wall claddings. Thus began the birth of rainscreen walls. Actually the birth was decades earlier—some old-timers showed me details from the 1960s with wall assemblies having an air space for drainage and ventilation between the cladding and sheathing. These guys said the practice never gained legs back then but the leaky condo crisis gave the kick-start to promote rainscreen and create a cottage industry. Soon, the city mandated that all claddings must be constructed as a rainscreen.
A decade later, I was back in the southwestern United States, part of a committee to review established procedures for flashing nail flange windows. I was very pleased to see the same basic diagrams were being implemented as good, economical flashing procedures. However, upon closer examination of the installation, graphics for flashing were altered to have reverse laps. I found the design and graphics team to ask why the procedure was changed. They admitted they had indeed changed it. When I asked why? “It looked wrong to us.”