When basement waterproofing goes wrong

A music room in Leeds.

A domestic basement waterproofing job illustrates the gulf between unqualified waterproofing ‘specialists’ and trained PCA Structural Waterproofing Group members.

My client bought a fine Victorian terrace with a basement already converted as a snug. There were no guarantees and at first glance the room looked very nice and seemed the ideal music room.

Once occupied, the problems became apparent; despite having a quality floor finish and being decorated, the basement became smelly and dank. I was recommended by the buyer’s surveyor.

On arrival I quickly discovered that the cavity drain membrane system, behind the dry lined walls had no drainage channels or a sump. The chipboard flooring was saturated and mould was growing behind the linings in abundance – hence the smell.

A cavity drain membrane does what the name implies – used below ground, without drainage, it is a waste of time and a disaster waiting to happen. Any CSSW surveyor will confirm this.

I specified Safeguard Aqua Drain channels and a Sentry sump system, combined with new Oldroyd CDM. Now the client has a basement music room to be proud of, which is guaranteed for ten years.

During the past housing boom very many basements were converted by builders and developers who lack training. Many work well, but some quickly become unwholesome places and the client has no redress. In these cases, the only solution is a complete rip-out, so it pays to get the work specified properly and obtain genuine guarantees before exchange of contracts.

Look for PCA structural waterproofing group members, who can offer GPT guarantees which really are insured for ten years.  And look for the letters CSSW, following the surveyors name, before you engage him/her.  That way you know that the company has been vetted as competent and the surveyor has been tested by written and verbal examination.


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Copyright © 2010 Preservation Expert. Legal Stuff: All the advice and information in the posts on my blog is made in good faith and is based on my experience and knowledge at the time of writing. However, nobody is infallible and whilst I’m confident that most of what I write about preservation issues is accurate, there’s a good chance there’ll be an error or two somewhere. I do change my mind about stuff, as I gain more experience. In view of this you must make your own decisions on whether to follow any advice I write and think about this; I could be wrong. No responsibility will be accepted by the author for any losses anyone may suffer as a result of any mistake or for the consequence of any action you take as a result of reading this blog. If you do suffer a loss, resulting from anything I’ve written, a verbal heartfelt apology will be your only compensation.