Bricks At Grade

Brick built on grade can result in the ingress of moisture, either from direct water run-off or the build up of snow. Excess moisture present in the brick during the freeze-thaw cycles can result in spalling of the brick. The Ontario Building Code and good building practice dictate that brickwork should be a minimum of 150mm (6") above grade. This requirement also applies to any level surface such as paving, patio decks or balconies. Furthermore, the ground should be contoured so that the water drains away from the wall. See Fig. A.

Base flashing should be installed below the bottom course of masonry, to prevent the upward migration of moisture due to capillary action (rising damp).

Always slope the grade away from the building. The masonry wall assembly should begin no less than 150mm (6") above the grade line.

Grade should be measured from the top of the finished surface. This means that grade should be considered to be the top of a wooden deck, a stair tread, a poured concrete balcony, or any sort of finished surface, be it paving brick, gravel, asphalt, or the earth in a planting bed.

Where wooden decks are built adjoining clay brick walls, the deck timber should be set back a distance of 40mm (1-1/2') from the wall, to allow for the drainage of water away from the masonry.