CSA A123.3-98

1.1

This Standard covers asphalt saturated organic roofing felt, with or without perforations, for use in the membrane system of waterproofing systems and in the construction of built-up roofs using asphalt systems.

1.2

The following types of roofing felt are addressed by this Standard:

(a) Type 1 – a roofing felt that may be used in the construction of a built-up roof membrane (when perforated), as an underlay felt beneath asphalt shingles (when not perforated), or as a building wrap beneath brick, stucco, siding, etc. It is commonly called No. 15 felt;

(b) Type 2 – a roofing felt used as an underlay beneath asphalt shingles, wood shakes, tiles, and other sloped roof coverings.

It is commonly called No. 25 or No. 30 felt.