CCMC evaluation of the effectiveness of ridge vents.

Gives brief details of the Canadian Construction Materials Centre's recent evaluation of three new ridge vent products made of either three-dimensional polymeric matting or moulded plastic. In its evaluation the CCMC determined the effective venting area of each product, and also assessed the product's ability to: sustain loads imposed by wind; prevent rain water entry; resist traffic loads during installation or roof maintenance.The evaluation demonstrated that the effective venting area varies significantly from one product to another and can be as low as 0.0045 m2 per linear metre or as high as 0.032. In general the more open the product, the better its venting performance. However, the openness of a product must be weighed against its other physical properties and its durability.