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Penetrating Damp Treatment in Hertfordshire

January 29, 2020

Premier 1st for Property Care was in Hertfordshire penetrating damp from high ground levels on an early 20th Century building, which for the last 80 years has been a small-town hospital.

At some point, they had contractors in to build a ramp for access for deliveries on trolleys, and possibly wheelchair users. 

In doing so the original slate damp proof course (DPC) was bridged and groundwater was able to bypass the DPC.

The salts, nitrates and chlorides, commonly found in our soil minerals, can be seen evaporating at the face of the brickwork above the top of the ramp.

Over the years those salts have migrated through the wall and internal plaster. These salts are hygroscopic; that is, they are capable of attracting and absorbing airborne moisture and humidity inside the building. When the hospital was functioning there was quite likely a humid atmosphere; a kitchen preparing hot meals and a laundry possibly too. Plenty of internal moisture attracted by the salts would have led to the saturation of the internal plaster. When the humidity drops the salts would also crystallise, causing destruction of the plaster.

The more the wall plaster decayed, the more the salts would find their way through…a continuing cycle of destruction. 

Perhaps the mistake the builders made was not to install a membrane between the external slope and the wall. A membrane would have prevented the transfer of ground moisture.

More of concern here is what the transfer of ground moisture through the wall could be doing to the internal timber floor structure. Damp structural timbers are at risk of fungal decay which at it’s worst can be devastating and destructive.

The solution?

If it is not practical or possible to remove the slope altogether, then once the internal plaster is removed a directly applied cementitious, physical or liquid membrane can be applied to the internal side of the wall before being re-plastered. This application would have to continue down into the sub-floor and to ensure the structural timbers were isolated from the wall and that sufficient ventilation was present to prevent a build-up of sub-floor humidity which can also lead to outbreaks of wood-destroying fungi.  

Thankfully the surveyors at Premier 1st For Property Care are experienced and qualified to identify, investigate and diagnose building defects and provide a solution and schedule of repairs in such circumstances. 

More importantly, perhaps, our experienced technicians have implemented solutions for problems like this for years.

If you have any concerns relating to dampness in your building, you will be in safe hands with Premier…. your first choice for property care

Contact us today for your property care or damp treatment project.

January 29th, 2020