We have a recurring washer drain back-up problem. every 3 to 6 months the drain stops up from the lint buildup . Plumbers tell us that it is due to the roughness of the main drains surface and it catches and collects the lint. Their solution is to jackhammer my slab and install a new PVC section,of course they say keep snaking it out. We are a family of three and it seems like a lot of lint goes down the drain? I have tried bleach and hot water to make the pipe slick and enzyme cleaners also. Any other suggestions?