Pine Shake report

INTERTEK TESTING SERVICES

Report on the Durability of Untreated Northern Pine Tapersawn Shakes

Salient points/Selected quotes:

Date of report: summer of 1997
45 untreated pine roofs were inspected for their condition
locations: 2 in Kelowna, BC; 22 in Calgary; 21 in Edmonton
roof shakes had been provided by at least four different manufacturers
roof conditions varied from no visible decay to extensive decay requiring major repair or complete replacement of the roof
"The main reason for decay on these roofs appears to originate because of moisture retention between the unexposed portions of the shakes and the interlay felt. This retained moisture provides an ideal breeding ground for the type of bacteria which destroys wood cells, especially in non-durable species like Lodgepole and Jackpine."
most of the problems regarding extensive decay were found on roofs over five years of age; decay was observed on roofs as little as four years of age
(Calgary) - six year old roofs: signs of decay that indicated extensive repair/replacement should be carried out
(Calgary) - seven years and older: most roofs require entire replacement
(Edmonton) - six year old roofs: most have sustained extensive damage due to decay and require partial or complete replacement
(Edmonton) - seven years and older: all roofs in condition of extensive decay; replacement necessary
(Edmonton) - nine year old roof: solid sheathing is noticeably spongy underfoot which is an indication of moisture and/or decay there as well
"...for the consumer's protection, immediate* action should be taken by the building authorities to ensure no further dwellings are roofed with untreated Northern Pine shakes."
* Approximately one year later (as of June 1, 1998), the Alberta Building Code has been changed to preclude using untreated pine for our rooftops.