Damp Surveyor

Information on specialist equipment, that our independent damp and timber surveyors often use to assist in diagnosing damp and timber defects; and during specialist building surveys. 

Using a Protimeter Surveymaster/ Surveymaster 2 / Protimeter MMS2, the relative scale (RS) and wood moisture equivalent (%WME) value for the property’s building materials have been assessed.

Where instructed, destructive (invasive) drilling can be undertaken to utilise deep wall probes.

The wood moisture equivalent (%WME) is the theoretical moisture level that would be attained by wood that is in moisture equilibrium with the material being tested.

Moisture readings are measured using two different methods and scales:

• Two prongs to detect electrical resistance of the material into which they are inserted. The Wood Moisture Equivalent (%WME) is a percentage scale 1 – 100%. In timber where readings are in excess of typically, 22%, this indicates that moisture is present in sufficient quantities for timber decay to occur.

• An electronic radio frequency detector to give relative readings up to a nominal depth of 19mm into the material assessed. The moisture readings give relative scale ranges from 1 – 999. The radio frequency detector is not affected by surface moisture and can therefore be used to distinguish between condensation and dampness in the material.

 Within the report, our findings are sub-divided into three colour zones, Green, Amber/Yellow, and Red indicating the severity of the moisture reading. In the Green zone, moisture levels are in a safe air-dry condition. In the Yellow zone, moisture levels are higher than normal but not critical and therefore a borderline state and further monitoring is recommended.  In the Red zone, moisture levels are excessive / too high. If sustained long-term, high moisture levels will lead to decay.

It is important to understand how an electronic moisture meter operates. The principle is straightforward; dry wood or masonry will conduct less electricity than wet. Thus, when moisture is present, the meter will reflect this. Whilst timber, regardless of species has the capacity to take up roughly the same amount of moisture, and so real percentages, can be obtained, this is not the case for other building materials (e.g. plaster, brick, stone or mortar). Therefore, the reading is only qualitative; the true moisture content of the material may be significantly higher or lower. This is because the meter cannot be calibrated to account for the variable nature of masonry. 

This is why when giving moisture readings of walls, we refer to the RS scale from 0RS (Bone Dry) – 999RS (Saturated). We use our experience of testing many walls, plasters and renders to advise on whether the Relative Scale value recorded is considered to actually be ‘wet’ or ‘dry’; as opposed to going on the meter’s electronic read out of ‘wet (red), ‘at risk (amber)’, dry (green)’.

We use a Protimeter MMS2, to determine whether walls, floors and ceiling surfaces are at risk from condensation. The MMS2 also allows us to measure a range of surface temperatures, surface and sub-surface moisture levels and air and building materials relative humidity levels.

Our Protimeter Psyclone / Extechs are hand held thermo-hygrometers designed to measure air relative humidity (%RH) and temperature within the building. We use this equipment to undertake condensation risk assessments.

We use a Ryobi Professional Tek4 Infrared Thermometer to determine temperature of building materials such as ceilings, walls and floors. This is used to determine if cold bridging, cold spots, lack of insulation, defective building materials or a high moisture content is present. The Thermometer can accurately measure temperatures between -20 and 310°C.

We use a FLIR E6 thermal imaging camera / Ryobi Spot thermometer to detect energy waste, cold spots, thermal bridging and moisture issues in buildings. 

The infrared camera shows exactly where the problems are and helps focus attention allowing us to properly diagnose areas with energy loss/moisture, which are not visible to the human eye.

Where appropriate, we use a Portascope MK3 / Ryobi Boroscope /mirror and torch, to inspect cavities and/or sub-floors. 

For commercial / extended surveys and flooding, we use Digital floor hygrometers, which indicate both relative humidity and air temperature. This enables the reading of Equilibrium Relative Humidity (ERH%) of floor screeds and slabs to BS8203 and BS5325 standards.

When undertaking invasive (destructive) testing, we use a Protimeter Salt Analysis kit to determine the presence of electrically conducting salts contamination on site. This enables a surveyor to analyses samples of wallpaper and plaster for the presence of soil salts. Certain nitrates and chlorides are deposited by evaporation of soil-water (rising damp) on the surface of walls. A meaningful analysis can therefore be carried out provided a wall has not been disturbed for several years. The test uses a colour change to indicate whether or not certain nitrates and chlorides are present in the assessed sample.

A Protimeter Speedy Calcium Carbide meter is used to test moisture levels in material samples using electronic balance and a pressure test procedure to assess for %moisture content in samples. 

Please note, not all equipment is carried on vehicles.