P.J. Kelly
Senior Product Quality Manager, Hanson Brick
ABSTRACT
This study was carried out on 19 brick, of various clay bodies, surface texture and various waterproofing sealers applied to some of the surfaces. The brick were placed in a plastic container such that the body of the brick was encapsulated within the container and only the face was exposed to the exterior. The space between the brick and the container was sealed so that the only path that moisture and/or vapour could enter or leave the encapsulated brick was through the face of the brick.
The brick samples were allowed to dry in an uninsulated and unventilated laboratory with the container open for the spring and until the successive weight changes were minimal. The tests were started in July 2001. Each of the samples was weighed, then submerged in water for a period of 24 hours (24 hr cold water absorption), removed from the water, drained and wiped dry and weighed again. The dry weight and wet weight were taken as the 0% and 100% measurements and used throughout the rest of the tests as the lower and upper moisture limits. The containers were then sealed. The brick were stored in a laboratory and the rate of drying monitored weekly for a period of five months.
After this drying period, the containers were placed at grade outside directly under the eaves of a single storey building, east elevation, located in Burlington, Ontario. This situation simulates a typical brick wall. The samples were exposed to the weather; rain, snow, wind and dry periods. The samples were weighed every month for a period of two years.
The study investigates the following:
- The drying rates of brick in a laboratory
- The moisture content of brick exposed to the elements for a period of two years noting the effect of the seasons
- The difference in rates of wetting and drying of brick with or without waterproofing sealer
- The effect of ceramic coatings and texture on moisture absorption and evaporation from the brick surface
KEYWORDS: vapour diffusion, clay, brick, waterproofing, sealers
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