Wall moistening
  Wall diagnostics

Methods for examination of wall moisture:

  1. Visual checking. (This is a rapid examination method on buildings of less importance.)
  2. Measurement of moisture content of the surface. (This is a preliminary examination for defining the places of sampling on buildings of high importance.)
  3. On-site moisture and salt examination. (This is a detailed examination carried out on buildings of less importance.)
  4. Laboratory examinations: moisture content; moisture saturation; pH value; total salt content; detailed anion test – sulfate, nitrate, chloride. (This is a full examination that is carried out on buildings of high importance.)
  5. X-ray diffraction examination. (This is a detailed examination of characteristic samples for total compounds of valuable parts on buildings of high importance.)

In general, these examination methods are built on each other. The spots of wall moistening and their extent are visually checked on the site. The experts are searching for the sources causing the visible moistening spots. Furthermore, they are searching for the traces of former insulation as well as for that of previous interventions. By applying the methods of the surface moisture measurement the degree of moisture concentration can be defined. Based upon the inference from these results either the superficial moisture absorbed by hygroscopic salts or the water condensed on the surface can be defined.

The on-site moisture and salt examination is, in general, the art of examinations of limited expenses. Its application is widely accepted in the practice. A defective conclusion has to be taken into consideration if the results are handled as ones of full value. It should be known, that the results of both examinations can be taken into consideration only with an accuracy of +/- 10 to 30 percent depending on the circumstances of the measurement. If there is no laboratory test result available for the saturation, the exact degree of saturation can not be defined only upon the moisture content. It has already happened in the practice to measure saturation degree of both 8m% and 32m% with bricks. Consequently, it is not possible to esteem a highlighted or selected value, e.g. 20-25 m%, in general. Though the total degree of salt is an important value when measuring the salt content, the anion composition is of the same importance, at least. The on-site examination does not cover either this one.

A comprehensive knowledge on the condition can only be obtained and acquired as a result of laboratory examinations. An ideal distribution of sample quantity taken from the walls is considered to be by creating one sample taking spot for each 20 meters of wall length: in the cellar in two heights, on the facades in three heights and on the ground floor in two heights. Moreover, depending on professional experiences further samples can discretionary be taken, either in each height. Also, according to the professional experiences, the samples taken from the external upper places must be examined for total salt content, although it is advisable to test all the samples for this purpose. According to the applied practice, all the samples showing a total salt content over 0,5 percent, which is considered to be of critical value, must be examined in details, i.e. also for anions. This examination indicates most precisely for the origin of contamination! The Austrian standardization, the ÖNORM, prescribes only this examination for salts! In general the sulfate salts generate less damage. Although, it has to be stressed, that according to our personal experiences, in a certain concentration this is also able to generate damages. Just opposite to this, the hygroscopic nitrate and chloride ions generate significant surface damages already in small quantities present. In the course of X-ray diffraction examination the presence of different compounds is tested in the samples. These examinations are exclusively accomplished for buildings of significant importance and especially for testing around the extremely sensible plasters or wall paintings within that. This kind of examination is suitable for defining the compounds within the samples with full certainty. These compounds definitely indicate the past and future chemical processes of actual damages. Because of considerable expenses these examinations are applied for testing locally limited places in buildings of overriding importance.

The main goal is to obtain as detailed optimal information as possible on moisture and salt conditions of wall structure of the building.