Anti-crack matting can be a vital stage in the process of laying natural stone tiles and can save you from a lot of problems down the line, so it is important to know whether your project requires it or not. DURAL produce an anti-crack matting product called DURABASE CI++ which will help to protect your beautiful stone flooring from the several problems that can occur when laying new floor. These include:
- Cracks in both new and existing subfloor - these can be transmitted through into the tiles leaving your newly layed stone cracked.
- Stresses in the subfloor - concrete floors will continue to shrink and expand for long periods after installation. Wooden substrates can be affected by moisture in the air. Over recent years the growth in heated flooring has dramatically increased the degree of movement within such floors. This “hot and cold” cycle places great stress on the tiled covering.
- Damp from the subfloor - The air channels within the design of anti- crack matting membrane allow moisture that would be otherwise trapped escape. This controlled “release” prevents problems within moisture sensitive substrates. This is particularly important when laying onto anhydrite subfloors, residual moisture from the screed itself can collect under the tiles and cause damage to the adhesive layer. Particular attention should be made to the residual moisture in such projects before work commences.
Used in conjunction with tiles, DURABASE CI++ decouples the tiles, bridges any cracks and has a waterproofing function. It also facilitates compensation for water vapour pressure if residual moisture is present. DURABASE CI++ decouples the flooring from the foundations. Any small cracks can also be bridged so that they do not affect the tiled surface. This makes it ideal for renovation work. With DURABASE CI++, tiles can be laid over screed as soon as it is possible to walk on the screed without causing damage (residual humidity approx. 4 %). Calcium sulphate screeds, which are sensitive to humidity, are protected at the surface from the ingress of further moisture.
Suitable subsurfaces are:
- Cement screed
- Calcium sulphate screed (anhydrite screed)
- Hot screeds
- Mastic asphalt screeds
- Synthetic laminates and coatings
- Plywood and chipboard
- Wooden floorboards
When cutting the matting to size, make sure that of the CI++ decoupling matting and the associated ceramic tiled surfaces are not force fitted due to the thermal-related stresses and footfall sound protection. Depending on the flooring construction and the specific site conditions, edge joints with a width of approx. 5–10 mm (or larger as required) must be produced.
- Use a 4 x 4 mm serrated trowel to apply the thin-bed mortar to the subsurface.N.B.: Never use a larger notched trowel, otherwise the decoupling effect of the CI++ matting will be impaired. The adhesive should be selected according to the subsurface type. The adhesive must bond and mechanically join to the carrier fabric of the DURABASE CI++- matting. With most subsurfaces, it is possible to use a hydraulic-setting flexible mortar, or a quick-bon- ding flexible adhesive in accordance with DIN EN 12004 / C2.3.
- It is essential that the entire surface of the backing fabric of the cut-to-size mats is embedded into the adhesive. Loose laying of the CI++ mats is not possible. Work in the matting using a pressure roller or other suitable tool. Here, pay attention to the adhesive bonding time. For use as a compound seal, additionally apply DURABASE WP sealing tape to the mat joints to water- proof. For inward and outward facing corners, use the prefabricated moulded parts. Work in expansion joints using loops of WP sealing tape to produce a waterproof seal.
- For indoor applications, tiles can be laid immediately after adhesion of the DURABASE CI++ matting using the thin-bed procedure and thin-bed mortar which fulfils the requirements of the surface covering. Here it is advisable to smooth out any mat depressions and then apply the thin-bed mortar using the trowel in a single work step. The notching size of the trowel must correspond to the tile format for tile laying. The tiles must be embedded across their entire surface into the adhesive. The indicated available laying time of the thin-bed mortar must be taken into account. In terms of working procedure, it is also possible to wait for the filler to harden before laying the tiles. For outdoor flooring surfaces, highly frequented areas and large-format tiles, tile laying may not commence until the CI++ filler has hardened.Tiles in thin material thicknesses (slim tiles and slim / 4-tiles) are not suitable (risk of breakage). Furthermore, small format tiles measuring less than 50 x 50 mm may not be used. To prevent damage to the installed matting, protection from extreme mechanical stresses should be provided by the use of running boards.
Please refer to the DURAL website for additional product information and installation guides.