Do I need to have a sump pump installed in my cellar if I am having it water-proofed?

Dear Kali, The key to the answer of your question is where you said the room is below ground, to meet the requirements of the manufacturers of the membrane system and British Standards fully, you would need to install a sump pump system. The system you mention (Cavity Drain Membrain) cannot deal with standing water and if not drained by a pump or gravity drainage system will fail catastrophically in the event of water build up. Even though the property has not flooded before a slow build up of ground/rainwater would still be possible. So the correct answer is yes - in the absense of any reliable drainage you will need a sump pump in that situation. Mike Davison cssw (certificated Surveyor in Structural Waterproofing)

Hi im Derek from refresh Carpentry and Building Ltd I recently have completed a similar Cellar referb in Portsmouth. I wouldnt think a sump pump was necessary. i fitted a snorkel vent and added a radiator plus fitting a DPM and tanking the walls this has fixed the problem for my customer its now warm and dry in the cellar hope this helps. Regards Derek

all the p20 tanking system does is direct the moisture/water that is in the cellar walls,down the outside of the membrane usually channelling it into a sump and pump system in the floor, which ejects the water into the mains once it reaches a pre set level, if you want to keep the cellar dry this is the system you need to use really, sounds like you need some air down there first , before you go ahead with work have a few sub floor airflow vents fitted to make sure its not just a ventilation problem,

without seeing your cellar it sounds to me you need fresh air down there .there are a few ways to do this ,the cheapest is to put vent pipes in every 2 metter and give it a chance to start working if you have the walls tanked you would just be throwing good money away untill you sort the ventilation problem out

if you are waterproofing the cellar by membrane yes you need a pump. ventilation ??? continuous operation extract ventilation ray

needs doing to b.s.8102 get it done right by a pca member not a builder good luck