Gravimetric Testing of Dampness in Buildings
Before calling in damp proofing contractors, you need to know if you have a genuine moisture problem (such as rising damp) or if you require a water leak detection service to trace and access a water leak before treating a damp building. The evidence of moisture in a building may manifest itself with unsightly black mould on walls or other evidence of water damage. Whatever evidence is present, the source of water ingress has to be established first.
The use of a damp meter can be misleading as it depends on three main criteria:
The type of material being tested with the damp meter
The relative humidity of the surrounding environment and
The use for which the room is being used.
We’ve all seen evidence of condensation on walls in a bathroom or kitchen. In these cases it is fairly obvious why there is moisture evident and possibly mould on walls as a result. Also, damp meters are usually calibrated to detect moisture in wood mainly, as wood is one of the most likely structural building materials to be badly affected by constant dampness and moisture.
But often there is a need to be far more scientific when testing dampness in buildings especially when they are made from materials such as brick, concrete, stone, plaster and so on. What is needed is a damp survey specialist who really understands gravimetric testing, as it is the only truly accurate method of testing for moisture in a variety of building materials.
What is Gravimetric Testing?
Gravimetric testing is the measurement of water content in a building material sample and testing its weight (gravity) in a range of controlled wet and dry conditions. The process will typically involve taking samples at various heights and widths across the area being tested. Each sample will be marked to log its location on the wall, this will help diagnose the problem if mapped out.
The samples are sealed and then transported to be laboratory tested to very accurate weight levels to determine their current condition, as they were taken from the test site. They are then placed in a controlled environment with a constant, known relative humidity (eg 75%), for at least 48 hours and tested again with the measurements being noted against the fresh sample results. The samples are then fully dried overnight with all the moisture removed to give a base dry reading that can be compared to site samples and the controlled relative humidity samples.
What this gives the damp survey specialist is vital scientifically controlled information on Total Moisture Content. This is the sum of 2 components:
Hygroscopic Moisture Content – moisture naturally bound into the material when in equilibrium
Capillary Moisture Content - moisture that fills the capillaries of a material, i.e. an active source of ingress
From this data, the required analysis can be made and the correct advice given by the damp proof survey as to rising damp, salt damp or condensation problems
Paradigm Reinstatements is based in Scotland and is one of the UK’s leading specialists in gravimetric testing of damp walls and dampness in buildings. They have in their technical arsenal a wide a wide range of gravimetric testing skills as well as state of the art trace and access systems to ensure the building reinstatement is professionally and speedily actioned.
As a result, Paradigm is one of the leading building reinstatement companies appointed by several of the UK’s leading insurance companies.
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