Remedial Timber and Damp Heritage Specialists
Wall Stabilisation Specialists

Damp Proofing company in Whitstable Kent Rising Damp independant survey survey Damp Proofing company in Canterbury

Dampness diagnosis

Building Surveyors, when carrying out inspections for Building Societies or homeowners, will check for dampness using an electrical conductance moisture meter. A moisture meter can indicate that moisture may be present in your wall but it can't tell you if that moisture is in sufficient quantities to require further action. (A Moisture Meter is calibrated for Timber and not masonry walls).

A Chartered Surveyor is therefore only able to detect surface moisture, and will often report: "there is evidence of dampness and remedial damp-proofing work in this respect is required". Alternatively: "you need to instruct a damp-proofing and timber treatment contractor to carry out a full investigation to investigate the full extent of the problem and the necessary repairs required, together with an estimate for any damp-proofing and timber treatments."

The purchaser may then proceed to commission specialist remedial treatment contractors offering a ‘free damp and timber survey’’ found on Google or perhaps recommended by the Estate Agent to inspect and provide a report and estimate.

These damp-proofing companies and surveyors, often members of the Property Care Association (PCA), also use electrical moisture meters and they are likely to solemnly declare the presence of rising damp in their report.

I was called in by the householder to give a second opinion on a Damp Survey carried out by a leading nationwide Timber and Damp company. What follows is an extract from the report prepared by one of their ‘surveyors’ who has CSRT CSSW qualifications. These qualifications are issued in a self-certified process by PCA themselves after a 3 day course. This was the surveyor’s evidence: Inspection of the internal wall surfaces of the property was completed using an electronic moisture meter where high moisture meter readings were observed to several areas.

And his conclusion and recommendation based on the above was:

“After consideration of the instrumental readings, soluble salt contamination and other relevant factors, it is assessed that external masonry elevations within the property are affected by rising and penetrating dampness and the installation of a chemical damp proof course is recommended to the areas indicated on the enclosed sketch plan”

Dampness diagnosis in the home
The above photos were included in the report to ‘prove’ the rising damp finding.

His instrument was the moisture meter. No samples were removed from either the plaster or the wall to test for the presence of ‘soluble salt contamination’. No ‘other relevant factors’ were mentioned and all this just appears to be the standard spiel.

Just sticking the prongs of a moisture meter into the wall and getting a reading is not a Damp Survey and is not indicative of ‘Rising Damp’. The moisture meter should be used to establish a ‘damp profile’ but not to provide a diagnosis.

There are 3 standards which all state quite clearly that 'damp' meters can't be used to diagnose damp. If a surveyor uses a 'damp' or resistance meter and comes up with a diagnosis, or recommendation based on using one, you need to insist that they refer to these standards - BS5250 - code for the control of condensation, BS6576 - code for the installation of damp proofing and BS 7913 - conservation of historic buildings. British Standard 5250: 2011 (Code of Practise for the Control of Condensation in Buildings) clearly states on Page 19 the following: B 8: Measurement of dampness “Accurate measurements of the moisture content of brick or mortar cannot be obtained by the use of electrical moisture meters because the presence of salts increases the electrical conductance of the water, giving falsely high readings. Gravimetric methods carried out on samples taken from the fabric give the most reliable results…”.

When I inspected the property I discovered that the dampness was caused in places by a bridged cavity which was packed by debris. This was causing the moisture to permeate the inner leaf of the wall. In addition, the old terracotta airbricks were blocked which reduced the under-floor ventilation causing condensation to form on the floor joists and on the base of the walls. The external walls had been painted with plastic paint and it had also been re-pointed in sand and cement mortar. This had trapped the moisture in the wall. I removed some bricks to check the condition of the wall ties as sand and cement repointing on top of an impervious coating can accelerate wall tie rusting due to the moisture retention. On removing the bricks to check the condition of the wall ties I found that the wall ties did need replacing

Other areas of damp were found to be caused by condensation. There was no need for another chemical DPC course. £4,000.00 saved by the Client.


Sample Case History

A Client commented recently on being presented with my Invoice: “That seems a bargain for finding the solution to my problem and most likely saving me a ton if anyone else had come to look. Feel very lucky to have come across you in my searches.”

Presenting Problem was damp internal walls. Cause was a leaking water pipe under the timber suspended floor which caused moisture to rise up the walls.

Dampness diagnosis

An additional problem was the fact that ALL the air vents had been blocked by the Insulation Company who had blocked the underfloor vents to prevent their retro-fitted blown insulation from entering the sub-floor space through the air vents.

Dampness diagnosis

Solution: Fix the leak and remove the vents to clear the openings and re-fit the vents. Allow walls to dry out naturally.

'Which' Magazine in 2011 in an article 'Unnecessary Treatments' found that of the PCA members it tested not one PCA member could tell the difference between a burst pipe and rising damp.