FURRING SHEET FOR WALL

PURPOSE:To improve the alkali resistance and ply separation of a base fabric without impairing the bonding property between mortar and the base fabric and consequently realize the durable base fabric by a method wherein the base fabric is produced by impregnating and depositing asphalt composition containing surface active agent with and to a non-woven fabric, a certain percentage or more of which is polyester fiber under the condition that the ratio of the amount of deposited asphalt composition to the non-woven fabric lies within the specified range. CONSTITUTION:The sheet concerned consists of a base fabric 1 and a waterproof asphalt composition layer 2, which is laminated onto the base fabric. The non-woven fabric 11 used for the base fabric contains at least 50wt.% of polyester-based fiber. If the content of said fiber is below 50wt.%, the dimensional stability of the resultant base fabric can not be maintained to the environmental changes such as the changes of outdoor temperature and humidity, resulting in causing cracks in mortar. As the asphalt composition, 10-70% of surface active agent-containing asphalt composition 12 in terms of the weight of the non-woven fabric is uniformly impregnated with and deposited to the non-woven fabric. If the amount of said composition is not more than 10%, insufficient improvement of alkali resistance and insufficient prevention of ply separation in non-woven fabric result. If said amount just mentioned above is not less than 70%, the gaps between fibers are filled up by the asphalt composition, resulting in lowering the bonding power between mortar and the non-woven fabric.