In our opinion the answer is a definitive ‘NO’.
Most waterproofed basement conversions in the UK don’t have huge water pressure issues and, as such, are just damp spaces. Some arguments we listen to state that, “it’s dry down there, the pump will never come on anyway”. These people, we feel, are really just wishing on a star.
We all know that climatic conditions vary greatly throughout the year, and winter water tables are vastly different to those at other times of the year. Therefore, a one-pump chamber really is something that should be frowned upon.
We know of cases where pumps are working overtime and coming on every 15 minutes if not more, and yet we still hear of cases of one-pump chambers. Effectively, the householder faces the scenario of a 15-minute window, should the single pump fail, before the chamber overflows and the system possibly fails – not acceptable in our opinion!
We all know that electrical items can develop faults; it’s something that happens. Is it wise, therefore, to risk system failure by relying on a single pump?
Let’s also think about what a pump is doing. It’s pumping water from a basement drainage system – a system that sometimes has small items of debris in its channels. It is easy for such items to get pushed through the drainage system and deposited into the sump chamber, possibly jamming the pump impeller which, if using a single pump, jeopardises the functioning of the whole system.
It doesn’t make financial sense in the scheme of a basement waterproofing system to have only one pump. We recommend that all waterproofing systems use a double-pump setup as standard, or risk a potential issue at a later date.
I am sure there are lots of single-pump chambers out there working correctly but, really, this is a dangerous situation for the contractor and the householder alike.
We would like to see a measure in place that insists on a double-pump system on every installation, with a monitor to track the pump levels and raise the alarm if the primary pump develops a problem. The householder and pump engineer would have time to repair the main pump but still be protected by the second.
We have just been approached by a junior school that has a flood issue in the basement because of a suspected mains drain issue. On inspection, however, a one-pump chamber had been installed which, after testing, was found not to be working and didn’t even have a pump servicing agreement – another post to follow on this matter shortly. We would like to hear from pump companies who are servicing these systems and hear about their findings.
In light of these issues, simply put, we don’t want to see any more single-pump systems – a message we wish to instil in all BWA members.
Thanks for reading – we’d love to hear your comments.