A speedy test, which is performed with a calcium carbide meter is another moisture testing device used to assist surveyors in damp investigation and diagnosis. Performing a speedy test is, however, a disruptive process and involves taking samples of masonry or plaster from the wall for analysis. For this reason, speedy tests are not normally performed during pre-purchase surveys.
A calcium carbide meter is a sealed vessel which is used to mix measured samples of masonry with calcium carbide. The calcium carbide will react with moisture present within the material and produce acetylene gas. The proportion of gas released is directly proportionate to the amount of moisture present in the material, therefore by measuring the gas, we can derive the total moisture content of the sample tested. The flask incorporates a calibrated gauge which is used to measure the pressure excreted in the cylinder by the gas which is read as a moisture content percentage.
Unlike an electronic moisture meter, a calcium carbide meter does give a quantitive reading which is proportionate to the amount of moisture present in the sample. The test, however, will measure the total volume of moisture in the sample and cannot distinguish between hygroscopic moisture and free moisture.
The total moisture content of a material is a combination of its hygroscopic moisture uptake in addition to its free moisture which is derived from other sources such as rising damp, penetrating damp or water leaks. The only disadvantage to a speedy test is that it cannot differentiate between the two.
In reality it's not in all circumstances. A speedy test could however, be problematic when being used solely for establishing the presence of rising damp.
The British Research Establishment Digest 245 'Rising damp in walls; diagnosis and treatment' recommends "To obtain conclusive proof for the presence of rising damp" you must compare the hygroscopic moisture content (HMC) with the Moisture Content (MC) of a material sample.
If you are performing a speedy test for this purpose you have no ability to differentiate between the two. To establish between free and hygroscopic moisture you will need gravimetric analysis which is a controlled laboratory process.
The speedy test and calcium carbide meter are, however, very useful in water damage, flood recovery and during drying regimes where often there is little hygroscopic contamination.
Overall, the calcium carbide meter is an excellent tool to aid surveyors in damp investigation and diagnosis. Provided calcium carbide meters are used by a trained, experienced and qualified surveyor who knows how to use them properly they do provide an in depth investigation tool for moisture profiling.
Our damp surveys are only undertaken by experienced and qualified surveyors who have been independently trained and examined by our leading industry bodies proving their knowledge and expertise.
Our surveys are conducted in accordance with British Standard Codes of Practice and industry guidelines.
Once complete our surveys will produce a bespoke report which will contain a comprehensive assessment of the problems identified during our survey. Our reports include our diagnosis, damage appraisal, recommendations, repair specifications and costs for repairs, if necessary.
Edited pictures along with category damage ratings are also included to assist your understanding about the urgency of any repairs needed.
Our reports are available in both printed media and/or secure electronic portable documents (PDF) for email.
If you suspect a problem and require a survey, or simply need advice please contact us.