Chemical testing of masonry materials, and sometimes soil and subcutaneous or groundwater, are an important part of the scientific and technical identification of the causes of damage. Chemical and petrographic tests should, as a general rule, complement the scientific documentation, especially in these cases., when there are valuable frescoes or paintings on the surfaces of walls or vaults, And, when it is intended to fuse the strained structure of walls or protruding plasters by means of injection procedures.

It should be noted, that not all mortars used in ancient times to tie up walls combine without harm to the whole structure with mortars currently used, and especially with mortars on a Binder of Portland or Clay Cement. Gypsum compounds in former masonry mortars when combined with cement mortars swell and have a detrimental effect on the strength of masonry.

Chemical tests of mortars should therefore give comprehensive data not only in terms of their morphological characteristics, but should also state, whether the mortars are chemically active or passive.

Chemical tests shall be supplemented by petrographic tests, which are intended to determine the type of materials, their structure and mineralogical composition. These tests shall be carried out in particular when, when the quality of masonry materials is uncertain and when the symptoms of damage indicate the action of active processes of disintegration of the structure.

Note, that also natural stones and brick have admixtures and compounds in their structure (for example. Sulphur, Iron, manganese, Carbon, Lime, plaster, clay crumbs, etc.), which are activated under the influence of improperly selected mortar composition during the maintenance of walls and instead of joining the structure cause its further destruction.

Chemical tests of mortars and petrographic tests of masonry materials are carried out on samples taken (Cut) from masonry substance. Samples are sent to the laboratory intact with the appropriate imprints.