Green roofs need adequate leak test systems | Journal of Commerce

The growing popularity of green or living roofs is underscoring the need to have an adequate test system in place to detect leaks that may occur in the protective roof membrane during or after construction.

This was the message for delegates attending the International Conference on Building Envelope Systems and Technologies (ICBEST 2010) July 27-30 in Vancouver.

?You, as professionals, should know how many leaking roofs there are in the industry,? said Klaus Burger, a German based researcher of leak detection and protection systems and member of the German Green Roof Association.

He said that leaks ? even pinhole sized ones ? could take years to work their way through the building and cause substantial damage before being realized.

David Vokey, an electrical engineer with Detec Systems, which offers detection and monitoring services, also spoke about membrane leak systems.

He said that for green roofs, these systems are becoming the assurance that insurance companies wanted to gain peace of mind.

Leaks can occur during installation from trades, from using the roof as a storage area, from materials being blown by the wind or transported by water during rainstorms, workmanship defects and also extreme weather and age.

There are two main types of systems used today: those used to check the membrane that will go beneath a green roof and ensure the membrane is intact before soil and plants are placed on it and secondly, those that remain in place under the membrane to continually monitor any leakage

Burger pointed to a study done in 2009 in Switzerland on 371 flat roofs built between 1931 and 1993.

The average roof life was 18.4 years with some failing as early as three years later.

?It has to be water tight from Day 1,? he said, adding that when leaks occur, building owners need to detect the leak area quickly to prevent damage.

It is quite costly to remove the whole planted area to search for a leak. The conventional way of testing whether a membrane works properly was the use of ?flood? test during the construction phase, said Vokey. He added that the process of flooding the roof ?wasn?t much fun?.

There was also debate about how long the water should be allowed to stand on the roof membrane.

This caused the industry to look at alternate systems.