Drain surveys to eliminate rising damp issues

By: admin | Posted on: March 2, 2020

So you’ve been told you have rising damp. Have you had every potential damp issue eliminated, or are you just treating the symptom?

Elimination is needed to offer a long term solution. It is often the case where no mortar/plaster sampling has been carried out (BRE DIGEST 245 / gravimetrics), and subsequent analysis, and some form of opinion has been offered in regards to damp diagnosis. Whether you’ve had a free damp survey, or paid for a damp survey you need to be sure the diagnosis is correct.

I often find issues with drains, soak aways, leaks that haven’t been checked previously.

The below image shows a completely blocked soak away in Wiltshire, resulting in rainwater backing up and subsequently the cavity wall insulation being blown fibre was saturated. Various reasons for the damp had been previously given by previous damp surveyors, and unfortunately none of the previous damp surveyors had inspected this. Sometimes to be fair this might seem unnecessary to carry out a drain survey, but if the insulation is wet, and there are very high free moisture readings noted at the base of the wall this would definitely need to be eliminated as a potential cause of the damp.

The below image shows another blocked drain, and root intrusion in Wiltshire. Again there was suspected rising damp issues adjacent this area internally at the base of the solid red brick wall. Gravimetric testing/sampling showed there was lots of free moisture at the base of the wall with no nitrates, chlorides (hygroscopic salts) present. If these hygroscopic salts were present at high levels depending on other factors, it can possibly point more to a genuine long term rising damp issue. In this instance it points to a potential drain issue, or a mains leak as the cause of the damp issues. I would expect an averagely competent damp specialist to understand this. Unfortunately the previous damp surveyor hadn’t checked this.

The below image shows an inspection to check the location of a soakaway. This can be located with our sonde equipment. The sonde is also used when marking up drainage defects where repairs need to be carried out. Unfortunately this soak-away was only installed 1.5meters away from the property, which could cause subsidence issues in the future.

If you have damp issues what should you do?

A really good tip is to get an umbrella and stand outside of your property during heavy rain. Pay attention to the gutters and drains, and look for any drips/leaks or drains backing up, or even drains slowly draining. You can sometimes see ponding water, which perhaps could be drainage issues or blocked soakaways. Make sure you keep gutters clear of leaves and moss, as these will shorten the working life of soakaways.

To learn more about the high percentage of drain defects in relation to rising damp please see our videos below. I offer root cause rising damp solutions, from small houses, to large Country houses.