Sometimes when there is heavy rain, water seeps into the basement through cracks in the walls and floor. We do have french drains and a sump pump. We tried to place plastic sheeting along one side of the house. Previously, there was some green algae growing on that side. Now the entire side is covered in green algae. What should we do?
I strongly agree with previous answer. Water vapour will condense on plastic and this will bring mould. Your french drains may need clearing out, they do get full of sediment, maybe you could use bigger size aggregate for better drainage ? Also make sure the basement is well ventilated with air bricks, perhaps you could get more fitted so there is a better air flow. If you already have enough air bricks, make sure they are not clogged up with dust, spider webs etc.
How about putting extensions on the gutter spouts so they move the excess run off water away from the foundation. The plastic will not keep the water from getting onto the basement. Since the plastic is NOT sealed to the ground water will flow under it and continue into the basement. Also, find and seal any cracks in your foundation. You can also hire a professional to waterproof the entire foundation. However, if you have a high water table in your area the water will come up from under the foundation during heavy rains.
