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Damp Proofing
Chemical & Tanking Systems​

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Cavity Extraction Limited Chemical Damp Proofing

Damp Proofing.

Rising damp is a common problem in our ageing housing stock either because no damp proof course (DPC) was installed at the time of construction, or a physical membrane has failed or been 'bridged'. In the majority of cases this can be simply rectified by the installation of a remedial damp proof course. This method is the most cost effective and requires the smallest amount of disturbance to the client.

Chemical Damp Proof Course

Cavity Extraction Ltd use an Industry leading range of remedial Chemical Damp Proof Course products. 

Rising damp comes from a water source outside the construction envelope finding its way into a property via capillary action within materials next to or within the construction.


Water containing salts are left on the surface of the structure and these are hygroscopic, attracting moisture, which exacerbates the issue. Cavity Extraction Ltd provides equipment to test for damp in masonry such as the Protimeter range, Thermal Imagery, Speedy testing as well as providing laboratory analysis to test for salts in masonry if required.

Where there is evidence of either no DPC or a failed DPC, rising damp will eventually appear resulting in area of damp and staining / discolouration up to 900mm above the skirting level along the whole length of the wall.

damp proof injection

The Solution


Remove the plaster surface to ensure the hygroscopic salts are removed. Then the DPC is injected into the mortar bed joint to each external / internal constructed skin. This will produce a chemical barrier which will stop any future ingress into the property. 

Once this process is complete you can either reinstate the plaster with a renovating plaster product Install a membrane to the offending wall before dot and dabbing plasterboard and skimming the wall surface bring the wall back to its virgin state.

All chemical DPC systems that Cavity Extraction Ltd use are in accordance with BS 6576 and are manufactured under our ISO 9001 (2015) QA scheme.

Tanking Systems


Cavity Extraction Ltd uses a studded polypropylene waterproofing membrane with a mesh welding to one side. It can be fixed directly to the damp / contaminated substrate using plaster plugs with the stud faced side of the membrane to the wall. This creates an air gap allowing air flow so the substrate can breathe whilst blocking the passage / ingress of moisture.

On the outer facing surface of the membrane is a meshed finish which can be plastered directly on to or if you choose you can dot and dab plaster boards with a finishing skim allowing a dry plastered finish to be achieved with no risk of contamination from damp or hydroscopic salts from within the wall.

tanking membrane

Quotation Enquiry
Damp Proofing

One of the team will be in touch soon!

Preston 01772 972343
Blackpool Office 01253 804303
Kendal Office 01539 523133

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