GRANITE STONE FACING
■ Outdoor exposure
■ Aboveground exposure
■ Exposure to rainwater
■ Masonry unit with a low absorption rate
Installation of any exterior facing is particularly important, since the facing is the first defence against water infiltration. One of the roles of mortar is to effectively manage rainwater flowing over the facing. Since our Canadian climate involves numerous freezing and thawing cycles, it is important that minimal water remain in the facing when the first freezing cycles occur.
To this end, mortars containing lime have long proven effectiveness. Furthermore, Canadian standard CSA A 179-14 indicates that a mortar rich in lime will likely resist water penetration better and reduce cracking (CSA A 179-14, pg. 44).
Granite stones have a very low absorption rate. So, the absorption of water contained in the mortar per masonry unit, which is required to ensure optimal adherence between the mortar and the masonry unit, is reduced. Outdoors, lime mortars will be of great help in managing rainwater. But with granite, this is not enough. We also recommend application of a slurry before installing granite elements.
TYPE OF MORTAR RECOMMENDED: TYPE S
■ Mortar recommended outdoors: King® 2-1-9
■ Mortar recommended indoors: King® 2-1-9 or King® Block