Spunbound fabrics are for those areas of light foot traffic, ideal for borders, under bark chips, gravel around patios, etc.  The fabric is manufactured to aid in the flow of water through the membrane to prevent that pooling of water  on the surface.  Scotplantsdirect offer two grades of spunbound fabric 50gsm and 70gsm.  The grade of fabric depends on the type of traffic in that area, ie 50gsm for light area, and 70gsm for little heavier traffic, but not suitable for driveways.  And if a roll is more than you need - we also sell weed fabric by the metre!