Moisture measurements in the building industry are just as indispensable for the examination of moisture-related building damage and defects as for general building acceptance or construction control. The same applies to functional and quality tests in the area of building modernization or building renovation.
Mineral building materials generally have a certain level of moisture balance. On the one hand, this is water chemically bound in the building material, on the other hand, it is monomolecular water adsorbing on the pore surfaces. This moisture corresponds to the natural moisture content of the respective building material. Only when the degree of moisture exceeds this, which varies depending on the building material, is it called a damp or wet building material or component. The difference between wet and wet is defined as follows in construction technology:
- moist = no visible water film on the building material
- wet = visible water film on the building material
If components and their building materials are moist or wet, the causes are relatively broad and can be given with the following examples:
- residual moisture due to construction
- faulty building sealing (e.g. floor slab, basement walls etc.)
- faulty airtightness level (e.g. removed loft etc.)
- condensate moisture (condensation failure)
- severe weather damage (flood, storm, etc.)
- broken pipes
- leaks (roof, floor slab, basement outer walls, etc.)
- damaged sewage pipes
- groundwater rise
- defect drainages
- improper window or door connections
- faulty component connections (e.g. waterproof concrete components etc.)
- aging of building materials and components
Examples of problems with damp structures and components:
- mold and algae growth
- efflorescence of salt
- frost damage
- cleaning damage
- deterioration of thermal insulation
- damage to furnishings
- health problems for users
There are numerous methods for measuring moisture in construction. The type of measurement to be selected depends on the desired accuracy and the substrate / building material to be measured. In addition to this, there is a need for clarification as to whether a non-destructive measurement or a measurement via sampling should be carried out.
The following methods of moisture measurement must take samples:
- calcium carbide method (CM-measurement)
- gravimetric method (Darr-method)
Non-destructive methods are usually carried out from the component surface. It should be noted here that not every measurement can be carried out everywhere and not every method or device delivers exact values. Examples of non-destructive measurement methods are very extensive and range from radiometric, acoustic, thermal to purely electrical methods. The most common ones are:
- microwave process
- resistance method (conductivity method)
- infrared process (infrared absorption / reflection)
- equalization moisture method
The expert office Holzmann-Bauberatung® offers all common methods for moisture measurement. For example, the scope of our expert moisture measurement includes surface measurements and depth measurements using different methods such as microwave measurement, resistance measurement or the Darr- and CM- methods etc.
We can also offer you quick measurements with inexpensive moisture indicators (ball head sensors) (e.g. Hydromette from Gann, BM 30/31 from Trotec, TFA Dostmann or similar). However, it should be noted that their results are not suitable as evidence from a scientific or legal point of view.
The costs for the various moisture measurements are fundamentally dependent on the type of measuring device or measuring method, the necessary examination times and the type of expert opinion that may be required, which are offered as follows:
- brief report with keyword-based listing of the measured values as the basis for out-of-court settlements
- Detailed construction report for court reports, insurance reports, arbitration reports, evidence preservation procedures or similar.
If the expert acts as a mediating construction expert, minutes of the conversation and / or results of the negotiations are also recorded. In all activities of the construction expert, it must be taken into account that the Holzmann-Bauberatung® expert office generally assumes a neutral position. The impartiality is confirmed in writing in every report.