rain

Morrison Hershfield Limited undertook to study and investigate the performance of the Rainscreen Principle applied to residential claddings on wood frame construction for the Canada Mortgage and Housing Corporation. The study included a full scale simulation, in the laboratory, of the rain penetration control performance of three cladding types with each having a sealed and leaky air barrier system. The three cladding types include vinyl siding, stucco, and a brick veneer. Ail cladding systems were mounted on a conventional wood frame wall.

Reports study of wind and rain over fifteen years and gives table of results. Reports measurements of wind pressure and driving rain on buildings. Discusses laboratory measurements of the tightness of facade elements under pressures of up to 50 Pa. and with temperature differences of -40 to +30 deg.C. across the facade. Describes pressurization of buildings and gives results of measurements in test dwellings. Discusses movement of joints in buildings and describes measurement of this movement.< Discusses permeability of both flat and sloping roofs.

In projects to rehabilitate old buildings in Canada, it is general practice to clear out the entire interior of a building, leaving only the structure and some or all of the exterior walls and roof. The new interior conditions impose more severe loads on the building envelope and hence walls and roofs must be upgraded. Discusses improvement of walls and roofs to increase airtightness, reduce rain penetration and conserve energy use. Discusses the effect of insulation and the location of insulation on the envelope performance and possible types of wall and roof modification.

States that concern for weathertightness requirements for windows has increased recently. Discusses standard methods for testing air leakage and rain penetration of windows. Illustrates some general findings on air leakage. Discusses relationship between air leakage and rain penetration. Outlines characteristics of leakage through doors.

Outlines the characteristics and physical properties of driving rain. Discusses natural wind and its strength, spectrum and velocity. Describes methods for the measurement of wind loads and of driving rain on buildings. Discusses methods of measuring the resistance of walls to driving rain and notes some limitations. Describes the protection of walls and joints from rain and discusses the formation of one-stage and two-stage joints.