Taken from  The Tile Association

The maximum weight of tiling which can be supported by a dry, well-adhered plaster background is 20kg/m². This is equivalent to ceramic tiles with a maximum thickness of 8mm plus tile adhesive or natural stone tiles with a maximum thickness of 7mm plus tile adhesive

The weight of tiling to a plasterboard background direct (without plaster skim) should not exceed 32kg/m². This is equivalent to a ceramic tile and adhesive with a maximum thickness of 12.5mm and natural stone and adhesive with a maximum thickness of 10mm.

It is important to emphasise that the weights quoted includes both the tile and adhesive.

Further advice should be sought either from the manufacturer, regarding the suitability of the adhesives and grouts and also guidance must be sought from board manufacturer regarding additional information on recommended methods for the installation of boards.

The following table offers general guidance to some common types of building board and the maximum recommended weights for tiling.

Porcelain tiles are ceramic tiles with a water absorption rate of less than 0.5 percent that are used to cover floors and walls. They can either be unglazed or glazed.

Large-scale production of porcelain tile is undertaken in many countries, with the major producers being China, Italy, Spain and Turkey. There are also countries undertaking small-scale production, such as Australia and strong growth in Brazil.

The hardness of the tile can be rated from zero to five according to ISO 10545-7 (also, ASTM C1027) test for surface abrasion resistance of glazed tile, and this can be used to determine suitability for various end use conditions.

The dense, hard surface of porcelain has made polishing a viable alternative to a glazed surface. This means that a tile can be fired, then a polish cut into the surface, creating a shine without a glaze.

Porcelain is denser and therefore heavier to handle; it is generally more expensive. Being harder, it is harder to cut and drill, which may make fitting harder and more expensive. Polished porcelain may need sealing, where ordinary glazed tiles do not.

Specialised cements are necessary for installation of porcelain tiles, and in the US specifications are set by the Tile Council of America, and supported by the Tile Contractors Association Porcelain, being denser and heavier than ordinary ceramic tiles, needs a stronger adhesive to hold the weight on walls. Therefore typical ready-mix adhesives are not recommended for porcelain.

When porcelain is first made, it is not absorbent, but the polishing process for making the unglazed surface shiny cuts into the surface, making it more porous and prone to absorbing stains, in the same way as natural stone tiles do. Unless they have a suitable, long-lasting treatment put on by the manufacturer, such as nanotech treatment, polished porcelain tiles will need sealing. Porcelain sealer’s are either water-based, which is cheaper, but does not last as long, or solvent-based.

Tanking all wet areas prior to tiling is essential.

 Bal kit

Tiling onto a wooden floor is a big no no , because it can cause your new tiles to crack with the natural movement and expansion you get with wood, The following over boarding should be used to decouple the tiles from the movement ...

Hardiebackerboard  Taken from there website click here

Why HardieBacker® Only backer board with a lifetime warranty Used in place of regular drywall, gypsum boards, glass mesh cement boards, and "floated" walls/floors Basic Composition: 90% Portland cement and sand with selected additives

1-800-9-HARDIE

Ditra      taken from website    click here for website

Schlüter-DITRA 25 is a polyethylene membrane with a grid structure of square cavities, each cut back in a dovetail configuration and an anchoring fleece laminated to its underside. Designed for tile and natural stone installations, Schlüter-DITRA 25 serves as a waterproofing membrane, a vapour pressure equalisation layer to accommodate moisture occurring at the underside of the substrate and an uncoupling layer for problematic substrates.

The substrate must be even and load bearing. To bond Schlüter-DITRA 25, use a bonding adhesive that is appropriate for the substrate. Apply the adhesive using a 3 x 3 mm or 4 x 4 mm notched trowel. The anchoring fleece on the underside of Schlüter-DITRA 25 must be fully engaged in the adhesive to provide a mechanical bond to the substrate. Please observe the open time of the bonding adhesive. Using the thin-bed method and following all applicable industry standards, set the tile or stone covering directly on the Schlüter-DITRA 25 in such a way that the tile adhesive becomes mechanically anchored in the square, cut back cavities of the Schlüter-DITRA 25 matting.

Summary of Functions

a) Uncoupling
Schlüter-DITRA 25 uncouples the floor covering from the substrate and neutralises the tensions between the substrate and the tile covering that result from the varying deformations of the materials. Likewise, stress cracks in the substrate are bridged and are, therefore, not transferred to the surface covering.

b) Waterproofing
Schlüter-DITRA 25 is a waterproof polyethylene membrane with a relatively high vapour diffusion density. Provided the joints, floor to wall transitions and connections to building fixtures are properly installed, Schlüter-DITRA 25 creates a waterproofing assembly with the tile covering that meets the requirements of the mandatory guideline "Recommendations on Waterproofing in Conjunction with Panelling and Tile and Paver Coverings in Interior and Exterior Applications," published by the German Construction Industry Association (ZDB). Exclusively use system approved thin-bed mortars for areas that require CE conformity or compliance with the general certificate of national technical approval. Please contact  us at the address shown in this data sheet for more details. Therefore, Schlüter-DITRA 25 protects the substrate against damage due to moisture penetration and aggressive substances.

c) Equalisation of vapour pressure
The interconnected air channels between the cavities on the underside of the Schlüter-DITRA 25 matting remain open. This allows moisture in the substrate to evaporate, therefore neutralising vapour pressure.

d) Load distribution (load impact)
The bottom of the square cavities in Schlüter-DITRA 25, which are filled with thin-bed adhesive, directly transfer the load impact on the tile covering to the substrate. As a consequence, tile coverings installed on top of Schlüter-DITRA 25 are highly load resistant. If high traffic loads are expected (e.g. in industrial locations), the tiles selected for the installation must be of the corresponding thickness and pressure stability. The requirements of the mandatory guideline "Ceramic Floor Coverings With High Impact Resistance," published by the German Construction Industry Association (ZDB) must be followed.

In areas with high impact loads, the tiles must be fully embedded in the thin-bed adhesive. The contact surface of Schlüter-DITRA 25 amounts to approximately 50% of the total surface. This can reduce the load bearing capacity in case of point loads. For high point loads, select a tile thickness that is capable of distributing the loads. Ceramic tile coverings should not be exposed to the direct impact of hard objects. The tile dimensions should be at least 50 mm x 50 mm.

e) Adhesive properties
Due to the bonding of the anchoring fleece into the thin-bed adhesive on the underside and the mechanical anchoring of the adhesive in the cut back cavities, Schlüter-DITRA 25 achieves a good adhesion of the tile covering to the substrate (laboratory test values: ~ 0.2N/mm2). Consequently, Schlüter-DITRA 25 can be used for wall and floor coverings. Anchor plugs may be used with wall coverings if necessary.

Dural provides a variety of matting systems for drainage, insulation and sealing. These make it easier to install floors of all kinds, even on difficult surfaces like old screed or wood, and they also protect the new floor covering from moisture seeping from below as well as preventing stretching or cracks. The advantages are obvious: greater robustness and durability, not only in homes but also where floors have to take plenty of punishment in commercial situations.

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