What are the main steps when using a single product dehumidifying render?
1. Remove all the damaged render with either hand tools or power tools to a level of at least 50 cm above the damaged area and, in all cases, to a height of at least twice the thickness of the wall. Also, remove any traces of loose or crumbling material, dust, mould and any other material which could affect the adhesion of PoroMap DEUMIDIFICANTE until the substrate is clean, sound and compact.
2. Clean the masonry with low-pressure water jets to remove any efflorescence or salts present on the masonry. Repeat this operation several times if necessary.
3. Any gaps or uneven areas in the masonry must be repaired by patching or tacking them with one of the mortars from the MAPE-ANTIQUE line and pieces of stone, brick or tuff with characteristics as similar as possible to the original material.
4. Saturate the substrate with water to prevent it drawing off water from the mortar, which could affect its final performance characteristics. Any excess water must be left to evaporate off, so that the masonry is saturated and the surface is dry (s.s.d. condition). Compressed air may be used to speed up this process. If the substrate cannot be saturated with water, we recommend that it is at least wetted to allow the mortars to adhere correctly.
5. Apply a layer at least 20 mm thick of POROMAP DEUMIDIFICANTE, starting from the bottom working upwards. If the thickness to be applied is more than 30 mm, POROMAP DEUMIDIFICANTE must be applied in several layers. Each layer must be applied without tamping or working the previous one.
6. After applying the mortar, wait a few minutes and level off the surface with an aluminium H-type or blade-type straight edge by going over the surface horizontally and vertically until it is flat. Remove any vertical guides, if they have been used, and fill the gaps with the same product. Finish off the surface of the render with a plastic, wooden or sponge float a few hours after the application, depending on the surrounding temperature and conditions. Never press down too firmly on the surface of POROMAP DEUMIDIFICANTE, otherwise its porosity could be reduced and, as a result, impede the evaporation of the moisture in the masonry.
7. If a finer-textured surface finish is required than the normal tamped finish of POROMAP DEUMIDIFICANTE, apply a layer of POROMAP FINITURA CIVILE or POROMAP FINITURA GRANELLO, depending on the required type of finish.
8. Paint the render with a silicate-based product (SILEXCOLOR Line) or a siloxane-based product (SILANCOLOR Line).
When should you opt for a single product system rather than a traditional system?
It is preferable to use the Mapei single product system rather than a traditional system particularly when you require a restoration system that is easier and quicker to apply, but at the same guarantees that the finished render will have the level of macro-porosity and resistance to salts mentioned previously.