Preparation & installation FAQs

Choosing the correct adhesive and grout is essential for a long-lasting and professional finish. Our Adhesive & Grout Selector helps you quickly identify the best products based on your tile type, substrate, and project location.

Mandarin Stone – Adhesive & Grout Selector

Transform your space by tiling directly over existing floors with confidence. This guide covers essential preparation, including cleaning, repairing, and priming old tiles, plus tips on adhesives, setting out, and movement joints. Follow these proven steps for a durable, professional finish every time.

Mandarin Stone – Tiling to existing floor tiles

This guide covers the essential steps for fixing natural stone externally, including flagstones and cobbles. From proper ground preparation and stable bedding layers to careful selection of mortar mixes and jointing materials, it ensures a durable, long-lasting installation that respects the unique properties of natural stone and site conditions.

Mandarin Stone – How to fix natural stone externally

Proper preparation and installation are critical when fixing 20mm porcelain tiles externally. This guide walks you through the process, including excavation, sub-base construction, mortar application, precise cutting, and professional grouting, to achieve a durable and flawless paved surface.

Mandarin Stone – Guide to fixing 20mm Porcelain to compacted sub 

Tiling a wet room requires careful preparation to ensure a fully waterproof and durable finish. This guide covers everything from preparing moisture-resistant substrates and installing waterproof membranes, to precise tile setting and sealing. Follow these steps for a professional-quality wet room that protects against water damage while delivering a sleek, functional finish.

Mandarin-Stone – How to tile wet room installations with Schluter and Ardex products

This guide covers the essential steps for tiling floors with under-tile heating mats, including substrate preparation, heating cable installation, tile fixing, and finishing. Following these best practices ensures a durable, crack-resistant floor that works seamlessly with your heating system.

Mandarin Stone – Tiling floors with under tile heating mats

Learn the essential steps to successfully install porcelain tiles on external concrete surfaces. From proper substrate preparation to selecting the right adhesive and grout, this guide ensures a strong, weather-resistant finish.

Mandarin Stone – How to fix porcelain tiles externally to a concrete substrate

Properly tiling over concrete floors starts with ensuring the concrete is fully cured, clean, and correctly primed. This guide walks you through surface preparation, setting out tiles, using suitable adhesives, and finishing with sealing and grouting. Follow these expert steps to achieve a durable, professional-quality tiled floor that withstands daily use.

Mandarin Stone – How to tile to concrete floors

Tiling over anhydrite screeds requires careful preparation and the right materials to ensure a strong, lasting bond. This guide covers essential steps, from drying and priming the screed to setting out tiles, fixing with cement-based adhesives, and finishing with sealing and grouting. Follow these expert tips to properly prepare the screed surface, choose suitable adhesives, and achieve a flawless tiled finish that stands up to everyday use.

Mandarin Stone – Tiling to anhydrite screeds

Ensure plywood floors are stable and secure before tiling, following BS 5385 standards. Use uncoupling membranes like Schlüter-DITRA to prevent cracking and apply flexible adhesives with correct tile layout and grout gaps. Seal and grout properly for a lasting finish.

Please see the full guide below for detailed steps and tips.

Mandarin Stone – Tiling to plywood overlay

Installing tiles over sand-cement floors with underfloor heating needs special care to avoid cracks and ensure a strong bond. In this guide, you’ll find step-by-step instructions on screed preparation, heating protocols, surface priming, and correct adhesive use to achieve a durable, flawless tiled floor.

Mandarin Stone – Tiling to sand cement floors incorporating underfloor heating

This guide, provided by FILA offers essential care and maintenance instructions specifically for honed terrazzo tiles. Using FILA’s specially formulated products, it outlines the best practices for protecting, cleaning, and preserving terrazzo surfaces to maintain their natural beauty and durability over time.

Fila – Honed terrazzo care & maintenance sheet

We provide comprehensive technical information tailored to each of our product types, ensuring customers have the detail they need to specify and use our materials with confidence.

For our porcelain products, this includes key performance data such as slip resistance ratings, ramp test results, and pendulum test values. All of our external porcelain tiles achieve an R11 slip rating, making them suitable for outdoor applications where safety is essential. They are designed to perform reliably in both wet and dry conditions and are fully frost resistant, ensuring durability in the UK climate.

Our natural stone range is assessed differently, as technical standards vary depending on the type and characteristics of each stone. Where available, individual technical data sheets are provided, offering detailed information specific to that material. These can be accessed directly on our website by navigating to the relevant product page, selecting the “Specification” tab, and downloading the corresponding product specification document.

Stone tiles are often packed very tightly into crates and may be wet at the point of production, sometimes carrying residue from various finishing processes. Because of this, it is recommended to wash stone tiles with a dilution of Fila Cleaner Pro and allow them to dry completely before every stage of the installation process. Tiles will often lighten in colour as they dry. Dry tiles are necessary prior to installation, as any unusual tonal markings can be strategically placed in less visible areas or used as cuts. At the point of installation, it is important to mix stone tiles thoroughly by opening all crates or pallets to ensure consistent distribution of any natural variation.

Patterned ceramic or porcelain tiles generally come as a random mix of designs and are boxed accordingly, while other porcelain tiles can be used to create various patterns or designs using a single tile type. Because of this, all tiles should be unpacked, and your installer should be fully informed of your laying requirements before starting the job. Stone and porcelain mosaics are supplied with either mesh backing or plastic coverings designed to hold the mosaic pieces in place during transport and installation. Over-handling these mosaics may cause chips to loosen or become dislodged completely.

Rectified tiles are mechanically cut after firing to create straight edges and sharp corners. This gives a more precise finish and allows for narrower grout joints. However, the size shown in the product name (for example, 600 × 600 mm) is a nominal size used for identification and layout planning. The actual tile may measure slightly smaller or occasionally slightly larger.

This is normal and happens because:

• Tiles are made from natural materials that shrink slightly during firing.
• Even after rectification, manufacturers allow a small size tolerance in line with industry standards.
• Tiles are produced in batches, and minor variations can occur between production runs.

For example, a tile marketed as 600 × 600 mm may measure around 597 × 597 mm. This does not affect performance or appearance once installed.

To ensure the best results:

• Always order sufficient tiles from the same batch.
• Avoid mixing calibres or batches unless advised.
• Have your installer check tile sizes before fitting.
• Allow for appropriate grout joints as recommended.

These small variations are standard in the tile industry and are not considered a defect. If you have any questions about tile sizing or batch matching, our team is happy to assist before you place your order.

Unlike rectified products, non-rectified porcelain or ceramic tiles are not mechanically cut to precise dimensions after the firing process. During firing, the wet clay naturally undergoes shrinkage and slight warpage as part of the manufacturing process. While these variations are carefully controlled, they are an inherent characteristic of kiln-fired tiles.

Once firing is complete, non-rectified tiles are graded and sorted according to size tolerance, but they do not undergo any additional cutting or edge refinement. As a result, a greater degree of size variation between individual tiles should be expected when compared to rectified tiles, which are cut to uniform dimensions after firing.

Non-rectified tiles are typically produced in smaller formats and are often patterned, decorative, or glazed. In these cases, cutting the tiles after firing could compromise the design, glaze finish, or visual integrity of the tile. For this reason, non-rectified tiles are intended to be installed with slightly wider grout joints, which help accommodate natural size variations and contribute to the overall aesthetic of the finished installation.

Before installation, it is essential that natural stone tiles are mixed from multiple crates or pallets to achieve a balanced and authentic variation in colour, tone, and veining. Natural stone is inherently variable, and unpacking and blending tiles from different batches helps prevent noticeable colour banding or clustering of similar tones in one area. For this reason, all materials should be unpacked and dry-laid where possible prior to fixing.

Patterned ceramic and porcelain tiles are typically supplied as a random mix of designs and are boxed to support this intended distribution. When installed as directed, this randomisation ensures the pattern appears balanced and visually pleasing across the finished surface. Other porcelain tiles, even those with a uniform appearance, can be installed in a variety of layouts or patterns, such as staggered, herringbone, or modular formats, using a single tile type.

To achieve the best possible result, all tiles should be unpacked, inspected, and approved before installation begins. This allows any issues to be identified early and ensures the overall aesthetic meets expectations. It is also important that your tile installer (fixer) is fully briefed on the intended layout, pattern, and any design preferences prior to fixing, as tiles that have been installed are generally considered accepted.

It’s important that your tiles are completely dry before installation. This allows you to inspect each tile for any tonal variations, colour differences, or surface imperfections. By doing so, you can plan the layout more effectively, placing tiles with unusual markings in less noticeable areas or using them for cuts where they won’t be as prominent. This extra step helps ensure a more uniform and visually appealing finish.

Minor damage, such as small chips to tile edges, can occasionally occur during packing or unpacking and is considered normal. Rather than discarding these tiles, they can be set aside and used for cuts during installation.

To achieve the best finish, tiling should begin from the centre of the room, with tiles dry-laid in advance. This helps avoid awkward or uneven cuts at the edges and allows the correct grout joint to be established, particularly when working with a mix of tile sizes or designs.

Uncalibrated natural stone tiles should be graded before fixing begins. The thickest tiles should be laid first to establish the finished floor level, while thinner tiles can be built up using a suitable large-format floor adhesive to ensure a flat and consistent surface.

Natural stone is carefully packed into crates while still slightly damp. This is because the stone is cut using water-cooled gang saws and then quickly finished and packed to preserve its quality. As the stone begins to dry naturally after unpacking, you may notice it gradually lightening in colour. This is completely normal and part of the natural drying process. As it dries, the stone reveals its true tones and unique characteristics, enhancing its natural beauty.

All stone, terracotta, ceramic, and porcelain tiles must be solidly bedded to ensure a durable, long-lasting installation. This requires full adhesive coverage across the back of each tile, ideally 100% contact with the substrate. Cement-based tile adhesives are generally the most suitable option for achieving this type of solid bedding, as they provide strong adhesion and consistent support for a wide range of tile materials.

For certain types of tiles, additional care may be required to achieve full coverage. Large-format tiles, natural stones such as travertine, or tiles with deeply textured or uneven backs may need to be “buttered” with adhesive on the back of the tile in addition to combing the substrate. This ensures that no voids are left beneath the tile, reducing the risk of hollow spots, cracking, or uneven settling over time. Proper bedding not only maximises the strength and stability of the installation but also helps maintain the flat, uniform surface needed for professional-quality results.

Back buttering is a tiling technique that involves applying a thin, even layer of adhesive to the back of each tile before it is placed onto the substrate. Instead of relying solely on the adhesive spread on the floor or wall, back buttering ensures that the entire tile surface comes into full contact with the mortar or adhesive. This method is particularly useful for larger tiles, uneven substrates, or tiles with low absorption, where air pockets or voids can easily form under the tile. By filling these gaps, back buttering enhances the tile’s bond strength, improves overall durability, and provides superior resistance to water penetration. Additionally, it helps prevent future problems such as tile cracking, hollow sounds underfoot, and delamination, making it a recommended practice for high-traffic areas, wet zones like bathrooms and kitchens, and outdoor installations.

Tile dimensions are listed as nominal, meaning slight variations in size and thickness can occur with most stone, terracotta, ceramic, porcelain tiles, and stone bathware. All surfaces to be tiled must also be , level, clean, dry, and as stable as possible. Because of these factors, it is important to fully discuss your requirements with your fixer before installation. This ensures they understand the product, any specific considerations, and your expectations for the finished result.

Proper lighting on site is equally crucial. It should closely replicate the lighting conditions of the final installation so that any colour variations, grout alignment issues, or surface imperfections can be identified and addressed during fixing. By combining clear communication with appropriate lighting, you reduce the risk of mistakes and achieve a high-quality, precise installation that looks and performs as intended.

This is where an experienced tiler plays a crucial role. Accurate setting out is a key stage of any tiling project and has a significant impact on the overall appearance of the finished installation. While the general rule is to work from the centre of the space outwards, careful planning is required to ensure cuts are balanced and the layout looks considered rather than forced.

The shape and format of the tile are also important factors in the setting-out process. Standard square or rectangular tiles may allow for more flexibility, whereas decorative formats such as chevrons require a much higher level of planning and precision. With these designs, alignment, symmetry, and consistent spacing are essential, and even small inaccuracies can become very noticeable. Taking the time to plan the layout thoroughly before fixing begins helps achieve a clean, well-proportioned result.

Under BS 5385, solid bed fixing must be achieved for: all floor tiling; wall tiling with tiles greater than 0.1m2(316mm x 316mm); and all tiling in all wet, external or swimming pool locations. To ensure you’re achieving solid bed fixing on walls, or when using a slump-free adhesive on floors, back buttering is required.

Stone, porcelain, and ceramic tiles all have different densities and properties, meaning they will behave differently when cut. Using the correct equipment is essential to achieving the best result.

Cutting should be carried out with a water-cooled bench power saw fitted with a diamond blade. The final aesthetic finish will depend heavily on both the cutting method and the operator’s skill level. Always use equipment and blades specifically designed for the type of tile being installed. Where required, the blade should be water-suppressed during cutting to control dust and keep it cool. High-quality diamond blades should be used at all times, as blunt or worn blades can cause shelling or chipping along the tile edge.

For certain materials or intricate cuts, it may be necessary to cut slightly outside the final line and then ‘dress’ the edge to achieve a clean, finished appearance.

These guidelines are general. For advice on specific products, please contact us.

Movement joints are essential to allow for expansion, contraction, and structural movement, helping to prevent cracks and damage in tiled surfaces. The main types include:

• Structural movement joints, which must align exactly with joints in the base structure to maintain continuity.

• Perimeter movement joints, installed where flooring meets walls, columns, or steps, except when walls are less than 2 metres apart.

• Intermediate movement joints, placed typically no more than 10 metres apart in larger floor areas to accommodate movement within the floor itself.

To ensure the long-term performance of tiled surfaces, it is essential to carry existing movement joints in the substrate through to the finished tile surface. These joints should be positioned directly over any changes in the background or substrate plane.

• Intermediate Movement Joints: These should be placed vertically at 4-metre intervals and at locations such as internal corners, columns, and other similar structural features.

• Horizontal Movement Joints: These should be positioned at junctions where the flooring meets walls or ceilings to accommodate any expansion or contraction.

Movement joints at junctions can be sealed with a suitable silicone sealant, or alternatively, a wide range of movement and control joint profiles are available from Schlüter Systems, which can offer further advice on their use.

Proper placement and sealing of movement joints will help prevent cracks and damage from substrate movement, ensuring the longevity of the installation.

Both walls and floors are subject to micro-millimetre movements, therefore it is necessary to include perimeter joints, and in some cases expansion joints. A perimeter movement joint is required where tiling abuts columns, steps, and perimeter walls (minimum 8mm). Expansion joints are required to force any movement to a controlled area of the room. Floors should be divided up into bays of size no greater than 40m² with an edge length no greater than 8m when underfloor heating is present. In large floor areas, non-heated, where perimeter joints are more than 10 metres apart, intermediate joints in normal floors should not exceed 8-10 metre intervals in each direction. The tile field should be as square as possible. The ratio between length and width should not exceed 1:2, e.g. 5 metres x 10 metres. On suspended floors the frequency of the movement joints may need to be increased to allow for flexing of the substrate. A movement joint should be positioned directly over the junction of two substrates, e.g., screed to timber. Please discuss this with your professional installer prior to installation to ensure British Standards are adhered to for your project

Underfloor heating increases the need for carefully spaced movement joints because heated floors expand and contract more than unheated ones. When using an uncoupling membrane like Schlüter-DITRA, the maximum area without intermediate joints should be 40m², with joints no further than 8 metres apart. Without such membranes, the max area drops to 25m². For suspended floors, movement joints must be placed more frequently and directly above supporting beams or walls to manage additional flex and expansion.

Self-levelling screeds are mixed with higher water content than conventional sand/cement screeds, which accelerates installation but requires much longer curing times. These screeds should be fully cured per manufacturer recommendations, with approximate curing allowances of 1 day per mm thickness up to 40mm, and 2 days per mm for thickness over 40mm. For cementitious adhesive installations, the screed must have less than 0.50% residual moisture before tiling.

Before tiling to an anhydrite (or gypsum or calcium sulphate) screed, you must first ensure it is dry. They generally dry at a rate of 1 day per mm of screed thickness for depths up to 40mm, and an additional 2 days per mm for thicknesses thereafter. For example, a 40mm deep screed requires 40 days to dry and a 50mm deep screed requires 60 days. To be sure it is dry, test the screed with a hygrometer meter such as the TRAMEX Hygrohood; readings of 75% RH or lower will mean it’s ready for tiling. After confirming it is dry, abrade the surface with suitable mechanised equipment to remove any laitance, loose debris and dust, and reveal the aggregate underneath. The anhydrite screed should then be primed with a single coat of ARDEX P 51 diluted 1:3 with water, applied in one continuous coat using a brush or broom. Once the ARDEX P 51 is dry, tile as normal using an appropriate ARDEX Cement-Based Tile Adhesive.

How to tile to anhydrite screeds using cement-based adhesives | Installation guide

Underfloor heating systems for stone, porcelain, or ceramic tiles must be installed in a minimum screed depth of 65mm, following British Standards. After curing, gradually bring the system to operating temperature at a rate of 5°C per day, maintaining it for 2-3 days before allowing it to cool down. During installation, ensure the temperature stays at 15°C, unless using specific types of screed like Anhydrite, Hemihydrate, or Gypsum.

How to tile to anhydrite screeds using cement-based adhesives | Installation guide

Usually an electric mat or cable system, the undertile heating system used should be suitable for use with natural stone, porcelain or ceramic flooring.  Bed the heating mat into a layer of Ardex K40 HB Levelling Compound which will protect the heating elements from any damage during the fixing process.

Schlüter-DITRA 25 matting should be installed on top of the cured Ardex K40 HB Levelling Compound to isolate the tile covering from the heated substrate underneath. This prevents movement stresses from damaging the tiled surface. Schlüter-DITRA 25 matting will not inhibit heat transfer or reduce the efficiency of the heating system.

Before tiling to heated sand and cement screeds, you must first ensure the underfloor heating has been commissioned. As per BS 5385-3, traditional sand and cement screeds should be at least 21 days old, at which point the underfloor heating can be increased by 5⁰C every day until the maximum water temperature advised by the underfloor heating manufacturer is reached. The underfloor heating should then be turned off for approximately 24 hours to allow the screed to cool down to room temperature. If site conditions are cool, maintain the screed and room temperature at 15⁰C or just above by adjusting the heat input accordingly. It can then be tiled as normal using the appropriate ARDEX Cement-Based Tile Adhesive.

If the screed is not heated prior to tiling or develops stress cracks, Schlüter-DITRA 25 matting should be used to bridge cracks and prevent stress transference to the tiles. After tiling, keep the heating off for 14 days, then gradually increase the temperature by 5°C per day, up to 40°C. Always follow specific guidance from your underfloor heating supplier for best results.

Sand and cement render provides a reliable vertical base for fixing stone tiles. It is suitable for tiles up to 15mm thick (≤38kg/m² approx) and can be installed up to a maximum height of 3.6 metres using an appropriate wall tile adhesive.

For tiles thicker than 15mm, up to 20mm thick (≤50kg/m² approx), the render must be reinforced with stainless steel EML (expanded metal lath) or a similar reinforcing mesh to support the additional weight.

It is essential that new renders are allowed to dry for a minimum of two weeks before tiling to ensure proper adhesion and prevent moisture-related issues.

How to tile sand/cement screeds with underfloor heating pipes | Installation guide

The screed must be at least three weeks old to enable movement caused by drying shrinkage to have taken place. After three weeks the heating should be switched on to heat gradually to manufacturer’s recommended operating temperature at maximum increments of 5°C every 24 hours. Ideally, leave the heating at this temperature for three days before allowing to cool gradually to room temperature. This allows the heating system to be tested as well as reducing the risk of the screed cracking due to thermal movement when the floor is heated.

We provide a complete range of professional fixing and sealing products to support every stage of tile installation. This includes adhesives, grouts, silicones, sealants, specialist cleaners, and surface preparation materials, everything needed to ensure a high-quality, long-lasting finish. In addition, we offer the full range of Schlüter products, renowned for their innovative solutions in tile trims, waterproofing, and underfloor heating systems.

While many of our most popular products are featured on our website, we also have access to a wide network of trusted suppliers. If you’re looking for a specific item not currently listed, we’re often able to source it as a special order, so it’s always worth getting in touch to discuss your requirements. Our team is happy to help you find the right products for your project, no matter how specific or specialised they may be.

Our range of ancillary products has been extensively researched over the years to ensure their best compatibility and performance with our stones and their intended applications. All of our suppliers are regarded as leaders within their industry. Prices are checked to ensure they are competitive in the marketplace, and we are happy to give you a no obligation quotation for such products alongside your stone. Where alternative products are being used, please check their compatibility with the suppliers or manufacturers before use. All stones photographed for this website, printed media and displayed in our showrooms have been finished with appropriate ancillary products recommended by ourselves. If you have any special considerations or needs for your installation, then please feel free to contact us so that we can offer the correct advice and products for the situation.

All advice and instructions, while they are the results of studies and trials carried out, are provided for informative purposes only.

Grout joints accommodate tile movement and should be at least 3mm wide, with the exact size depending on the tile’s material and finish. Textured stone tiles typically require wider joints of 6–10mm, while porcelain tiles can use narrower joints around 3–5mm.

Grout joints allow for tile movement and should be at least 3mm wide, varying with tile size and finish, textured stones needing 6–10mm, smoother stones and porcelain about 3–5mm. Joint widths must accommodate tile size variations and patterns like opus layouts. Ardex FL Flex Wall & Floor Grout is available in 10 colours to complement your tiles, and grout colour affects adhesive choice, as grey adhesive may shadow through light-coloured grout.

Grouting should be done at least 12 hours after fixing, with joints clear of dust and residue. ‘Slurry’ grouting is necessary for unfilled Travertine, some Limestone, and occasionally other tiles to fill pits and crevices, while other stones and porcelain should be pointed to avoid grout residue. Wipe off grout residue during grouting and clean with dilute Fila Cleaner Pro before sealing.

A majority of tile adhesives, grouts, and levelling compounds, including Ardex products, are formulated to perform best at around 20°C. Higher temperatures can speed up setting times, reduce workability, and increase the risk of shrinkage or cracking due to accelerated drying and warm, dry winds. Understanding these challenges is essential for a successful install.

We offer rapid or standard setting adhesives in either white or grey. Click here to view our full range of Ardex Tile Adhesives.

Fast setting adhesives allow moisture to disperse more quickly so are best for use with large-format natural stone, terracotta and porcelain. This helps to prevent various reactions that could be caused by the moisture retention of the tile.

Standard setting adhesive has a longer working time, which allows more time to make the minor adjustments and tweaks which are necessary when fixing porcelain including intricate patterns.

Generally speaking the substrate being tiled would be where the adhesive is applied/trowelled but good practice would also see the tile ‘back buttered’ on occasion, examples of which would be if the tile is slightly bowed, uncalibrated or where the back of the tile is uneven. The main purpose is to ensure a full solid contact layer is achieved leaving no voids within the adhesive bed between the tile itself and the substrate its being fixed to.

Pot life is also known as working time, and they both refer to the length of time that the mixed product remains usable and workable inside the pot/bucket after it has been mixed. Open time is the length of time that tile adhesive ribs remain wet and able to receive tiles (before skinning over) after being spread onto the wall or floor. Adjustment time is the amount of time in which a tile can be adjusted or moved after it has been fixed into the freshly applied tile adhesive.

• Storage: Keep all Ardex products out of direct sunlight. If stored outside, ensure they’re shaded and weather-protected. Don’t overlook materials left in vans — they can heat up fast.

• Mixing water: Run water until cool before use. Shade hosepipes, and avoid using sun-heated water from buckets or tanks unless adequately protected.

• Mixing tools & area: Mix in shaded zones to prevent tools overheating. Clean tools promptly to prevent material buildup or cross-contamination.

• Substrate temperature: Warm surfaces set products faster. Use thermometers or infrared devices to plan. Shade, tent, or work early to keep substrate temps in check.

• Substrate prep: Highly absorbent surfaces may dry too fast. Dampen them or use a 1:7 mix of water and Ardex P51 primer to control suction.

• Working area size: In hot conditions, reduce your working area to ensure materials are placed and finished quickly.

• Protection against accelerated drying: Use shading and wind breaks where possible. For screeds, consider using an impervious sheet to limit drying from the surface.

Tile backer boards are available in various materials, including cementitious, glass-fibre reinforced, and extruded polystyrene options. These boards are typically either water-resistant or waterproof and come in different thicknesses, each with varying weight-bearing capacities.

When properly screw-fixed to walls, backer boards typically offer a load-bearing capacity of 40-50 kg/m², which is suitable for stone tiles up to 15mm in thickness. Some backer boards are designed to handle heavier loads, accommodating 60-70 kg/m², making them ideal for thicker materials like Splitface tiles. However, these cladding or panels may require additional support until the adhesive has fully cured.

For specific details on load-bearing capabilities, it is always recommended to consult with the manufacturer of the backer board.

Used for multiple purposes, Schlüter-DITRA 25 matting is a membrane with a 3mm thick grid structure and is designed to act as an uncoupling layer for problematic substrates. Differing floor substrates can be overlaid with this matting to eliminate stress cracks from lateral movement at their abutments, it may be necessary to use a movement profile to alleviate any vertical movement; it can also be used to bridge screed cracks

All types of wood or boarded floors are particularly affected by moisture and flex. These floors should be overlaid with a suitable construction board, screw fixed at 300mm centres across the board and 150mm centres along the edges to minimise movement. Schlüter-DITRA 25 matting serves as a waterproof membrane and as a vapour pressure equalisation layer for floors to accommodate moisture occurring at the underside. It also uncouples the floor covering from the substrate and prevents the transfer of lateral stresses to the tiled surface.

If using Schlüter-DITRA 25 matting, then the minimum tile size that can be used is 50mm and the maximum adhesive bed thickness on top is 10mm.

Un-cured mortar screeds, heated screeds, floating screeds and Gypsum screeds can be subject to deformation due to residual moisture, shrinkage, load stresses or temperature changes. Using Schlüter-DITRA 25 matting and providing the substrate is sufficiently load-bearing, the tile covering can be installed immediately.

For any queries, please contact us.

For timber substrates, install a suitable tile backer board to create a clean, dry, and rigid surface. Fix underfloor heating cables embedded in ARDEX levelling compound, then apply Schluter-DITRA matting with ARDEX adhesive. Tiles are fixed with a flexible adhesive, keeping the bed under 10mm when using DITRA.

Lay tiles from the room’s center with minimum 3mm grout gaps, providing 6mm perimeter movement joints filled with flexible sealant to prevent cracking. Use a polymer-modified flexible adhesive matched to tile and grout colour, apply with a notched trowel, and ensure full contact by twisting tiles into place. Clean adhesive residue before it sets and avoid walking on tiles until cured.

Cut tiles using a water-cooled diamond blade saw to prevent chipping. After adhesive dries, clean tiles and seal natural stone before grouting. Porcelain usually only requires grout sealing. Mix grout carefully, grout joints, clean excess grout, and buff dry. Use Fila Instant Remover on porcelain if needed.

How to tile to floors with under tile heating mat | Installation guide

A dry level screed is an ideal fixing substrate. New screeds usually need to cure for a minimum of 1 week for every 25mm of screed depth, although the installation contractor should always be consulted for more specific timescales.

If time does not allow for this then Schlüter-DITRA 25 matting can be installed on a drying screed as it allows moisture in the substrate to evaporate through its air channels, thus neutralising vapour pressure and bridging any cracks that will occur through the natural drying out process. If this is done, then the movement joint at the perimeter of the room must be left open.

Uneven floors can be overcome to a certain extent with Ardex K40 HB Levelling Compound which can be used to create a smooth & level surface prior to tiling.

For faster installation on drying screeds, Schlüter-DITRA 25 matting can be used to neutralise vapour pressure and accommodate moisture content of up to 2.0%. It also helps reduce the risk of cracking by acting as an uncoupling membrane. Before tiling, ensure the surface is sanded to remove laitance and vacuumed. Depending on the screed type, use Ardex P51 Primer: for smooth, non-porous calcium sulphate screeds, mix with 0.5 parts water; for absorbent screeds, mix with 3 parts water.

Prior to installation, it is important to identify your substrate as the products needed for the correct installation of your tiles will vary based upon this. A substrate is the surface which sits beneath the tiles, the installation method will vary depending on your substrate and tile. A professional installer who has experience installing on to your substrate type is critical and they can also ensure the suitability of your chosen product to achieve a fantastic end result.

The key to preventing problems occurring after the installation of your tiles is the correct preparation of the substrate prior to fixing. All substrates that are to be tiled to, be they floor or wall, should always be suitably prepared; they should be clean, flat, level, free from movement and free from anything which could be deleterious to adhesion.

Correct identification of the substrate is vital to ensure the correct advice and ancillaries are provided. With the increasing use of large format materials on walls, it is imperative to ensure that the substrate has a suitable weight bearing capability to accommodate the desired material.

Plaster skim, existing tiles, and painted walls are generally not suitable as substrates for stone and porcelain tiles due to their lack of the necessary weight-bearing capacity. These surfaces may not be strong enough to support the load of heavier materials, potentially leading to issues with adhesion or long-term stability.

To create a suitable surface for tile installation, a proprietary tile backer board such as Schlüter-KERDI-BOARD is recommended. This board is waterproof and insulating, making it ideal for use in both dry and wet environments.

The backer board should be primed where required and screw-fixed firmly to the underlying substrate, ensuring a stable and durable surface for affixing tiles. This preparation is essential for achieving a successful and long-lasting tile installation.

Before starting the tile installation, it’s essential to properly prepare the floor. Any loose or damaged tiles should be removed, and the floor must be thoroughly cleaned and degreased to ensure proper adhesion. This is particularly important for areas where previous tiles may have left behind residue, dust, or oils.

If installing vinyl tiles, it’s important to seal the surface prior to fixing with the appropriate adhesive. This helps to prevent any adhesion issues and ensures a secure bond with the new tiles.

For unglazed tiles or natural stone, once they’ve been properly cleaned, they can generally be adhered directly to the substrate with a suitable adhesive. No additional surface treatment is necessary for these types of materials as long as they are clean and free of contaminants. This process provides a clean, smooth surface for secure installation.

Substrates should be as flat and level as possible. British Standards recommend a surface regularity of SR1 for most tiling, which means no deviation greater than 3mm under a 2m straight edge. Excessive undulations can lead to lippage, poor adhesion, and an unprofessional finish. Levelling compounds or screeds may be needed to achieve the correct tolerance.

As per BS 5385, the following drying times should be allowed before tiling: Concrete: at least 6 weeks, Traditional sand and cement screeds: at least 3 weeks Traditional sand and cement renders: at least 2 weeks
Plaster: at least 4 weeks. These backgrounds shrink as they dry; to avoid the risk of debonding, tiles should be fixed after these times.

Preparation, as well as suitability, will greatly depend on the substrate itself. For example a plasterboard wall will require a different level of preparation compared to a ready to tile construction board. Waterproofing, in necessary areas, is critical and very much part of NHBC regulations, we work closely with both Ardex and Schluter who offer a comprehensive range of products for both substrates and tanking systems.

Stone tiles are often packed into crates very tightly, are wet at the point of production and may have some residue from the various finishing processes employed. Because of this it is recommended that stone tiles are washed with a dilution of Fila Cleaner Pro and are allowed to dry completely before every stage of the installation process.

Check that all surfaces are clean, dry, and free from contamination. Degrease existing tiles and remove any sealants, as they can prevent proper adhesion. Repair any loose tiles or surface voids with ARDITEX NA Ultra-Rapid Smoothing Compound.

• If levelling is not required, apply a single neat coat of ARDEX P 4 Primer using a short pile roller or brush. Once dry (30–60 minutes), it forms a textured surface ready for tiling with an appropriate ARDEX Cement-Based Tile Adhesive.
• If levelling is needed, apply ARDITEX NA at a minimum depth of 3mm directly over the existing tiles without priming. It dries in as little as 3 hours and can then be tiled as normal.

When tiling, use a solid-bed technique with a suitable notched trowel to achieve full coverage. Butter the backs of tiles with deep profiles if needed. Choose the correct adhesive colour to match your tile and grout to avoid shadowing, white adhesive for pale tiles and grout, for example.

As you work, regularly lift a tile to check for full adhesive contact. Clean any adhesive residue from the tile surface before it sets. Once the adhesive has fully cured (approx. 3 hours for rapid-set, 24 hours for standard-set), you can proceed with grouting and sealing if needed.

 Tip: Always plan your tile layout in advance and include perimeter movement joints (minimum 6mm) filled with a flexible sealant like ARDEX ST to prevent stress-related cracking.

For best results and detailed instructions, be sure to check out the full installation guide below.

How to tile to existing floor tiles | Installation guide

Before tiling to bitumen adhesive residues, they should be levelled with ARDITEX NA applied 3-6mm deep direct (without priming). It will dry in as little as 3 hours, and can then be tiled as normal using an appropriate ARDEX Cement-Based Tile Adhesive.

Plasterboard that has not been skim coated with a finish layer of plaster can support tiles up to 10mm or 12mm thick (≤32kg/m² approx). However, the paper face of the plasterboard must first be sealed with a coat of Ardex P51 Primer mixed at a ratio of 1:4 parts water. Allow the primer to dry before fixing tiles with Ardex X7 or Ardex X7 R Wall & Floor Adhesive.

It’s important to note that plasterboard is not suitable for use in wet areas, such as wet rooms or areas exposed to consistent moisture.

Before tiling, ensure the concrete is fully cured, clean, and properly primed. Begin by laying out the tiles from the center of the room, allowing for suitable grout gaps and installing movement joints around the edges. Use an adhesive that matches the tile colour, applying it evenly to ensure full contact. Cut tiles with a water-cooled diamond saw and promptly clean off any adhesive residue. After fixing, clean and seal natural stone tiles before grouting. Finally, grout carefully, clean the tiles thoroughly, and apply flexible sealant at movement joints to achieve a smooth, durable finish.

For full instructions and expert advice, check out the complete installation guide.

How to tile concrete floors | Installation guide

Before tiling to plaster, you must first ensure it is at least 4 weeks old and that the total weight of the tiling will not exceed 20kg/m2, as recommended by BS 5385. You must then wire brush the surface to remove any dust. The plaster should then be primed with a single coat of ARDEX P 51diluted 1:3 with water and applied with a brush. Once the ARDEX P 51 is dry, tile as normal using an appropriate ARDEX Cement-Based Tile Adhesive.

You don’t need to remove existing grout if it’s solid and level with the tiles, you can tile over it. However, if the grout is cracked, loose, or deeply recessed, you’ll need to fill or level it first to ensure a smooth, stable surface for the new tiles.

Before tiling to gypsum (or calcium sulphate) floorboards, they must first be primed with a single coat of ARDEX P 51 diluted 1:3 with water, applied in one continuous coat using a brush or broom. Once the ARDEX P 51 is dry, it can then be tiled as normal using an appropriate ARDEX Cement-Based Tile Adhesive.

If levelling isn’t required, prime plywood floors with a single coat of undiluted ARDEX P 51 applied with a brush or broom. Once the ARDEX P 51 is dry, it should then be overlaid with a suitable tile backer board or uncoupling membrane such as Schluter Ditra Matting, which can then be tiled as normal using an appropriate Cement-Based Tile Adhesive. If levelling is required, level over the plywood with ARDITEX NA applied direct (without priming). It will dry after 3 hours and should then be over sheeted with a suitable mechanically fixed tile backer board, which can then be tiled as normal using an appropriate ARDEX Cement-Based Tile Adhesive.

How to tile to plywood overlay | Installation guide

A tanking system, which can be either a waterproof membrane or a liquid-applied coating, is essential to create a moisture resistant barrier beneath the tiles. This protective layer prevents water and other forms of moisture from penetrating through to the subfloor and walls, thereby safeguarding the structural integrity of the building. By applying a tanking system, you reduce the risk of water damage, mould growth, and deterioration of materials. Proper installation of this waterproofing layer is crucial to ensure long-lasting protection and to maintain a healthy, dry environment beneath and behind the tiled surfaces.

How to tile wet room installations with Schluter and Ardex products | Installation guide

When planning a wet room, the background must be stable and rendered watertight before tiling begins. Tiles alone don’t create a waterproof layer, so the substrate should be waterproofed or ‘tanked’ using suitable materials like Schlüter waterproofing membranes, sealant adhesives, and drainage systems. Always use water-resistant adhesives, grouts, and substrates, and avoid materials vulnerable to moisture damage. Choose tile materials carefully, porcelain tiles are non-porous and slip-resistant, while natural stone, though beautiful, is porous and may react to water over time. Any necessary falls should be incorporated into the substrate, with Schlüter’s preformed shower bases and floor drains available to assist.

How to tile wet room installations with Schluter and Ardex products | Installation guide

Proper preparation and technique are essential when installing 20mm external porcelain tiles over a concrete base. This ensures long-term performance, durability, and a professional finish. Below is a step-by-step overview of the process:

1. Preparation:
Ensure the concrete is fully cured, at least 6 weeks (or 3 weeks for cement-sand screed after curing). The surface must be clean, dry, and free from dust or contaminants. Wire-brush any dusty areas. If necessary, level the surface with ARDEX K 301 Exterior Self Levelling Compound.

2. Fixing Tiles:
Use a suitable cement-based adhesive like ARDEX X 7 R S1 or ARDEX X 11 W (for extended working time). Apply adhesive with a solid-bed notched trowel at a 45° angle, then press tiles firmly in place with a twisting motion to form a full 3–4mm adhesive bed. Butter the tile backs if they have deeply keyed profiles. Work in small sections, clean off excess adhesive promptly, and avoid walking on the tiles for around 3 hours.

3. Cutting Tiles:
Use a water-cooled diamond-blade bench saw designed for cutting 20mm porcelain. Always use sharp, high-quality blades to avoid chipping. For large cuts (more than 25% of the tile), cut from the internal to the external corner, ideally at a 45° angle.

4. Grouting:
Once the adhesive has cured, rake out any excess mortar from joints. Use ARDEX FLEX-FL grout, mixed manually at approx. 4:1 (powder:water), and apply with a rubber float. Work diagonally across the tiles to press the grout fully into joints.

5. Cleaning:
Remove excess grout once it becomes touch dry with a damp sponge, then buff the surface with a dry cloth. For stubborn residues, clean with Fila Deterdek. Always trial a small, inconspicuous area before grouting; seal the tiles if there’s any risk of grout staining.

How to fix porcelain tiles externally to a concrete substrate | Installation guide

Installing outdoor porcelain requires careful preparation to ensure durability, proper drainage, and a clean finish. Below is a summary of the key steps involved in the process:

• Excavation: Excavate to a depth that allows for the sub-base, mortar, and paving thickness. Ensure the finished surface is at least 150mm below the damp-proof course (DPC) of adjacent structures.
• Sub-base: Use a well-graded Type 1 granular material, compacted in 75mm layers. Avoid materials with organic content. The finished sub-base should have a longitudinal fall of 1.25% and a cross fall of 2.5% for drainage.
• Laying Paving: Mix tiles from different packs for a consistent finish. Lay tiles on a full mortar bed (1:4 cement/sharp sand), 15–30mm thick. Apply a slurry bond (Ardex P51 and cement) to the tile backs before laying. Tamp tiles gently into the bed and adjust for level and stability.
• Cutting: Use a water-cooled diamond blade saw suitable for 20mm porcelain. High-quality blades are essential to avoid chipping. For large cuts (over 25% of a tile), cut from inner to outer corner at a 45° angle.
• Grouting: Use Ardex Flex FL grout. Rake out excess mortar from joints before grouting. Mix grout by adding powder to liquid and apply using a rubber float, pressing grout fully into joints.
• Cleaning: Remove excess grout once touch dry using a damp sponge. Buff the surface dry and use Fila Deterdek for stubborn residues. Trial a small area first to check for staining, seal tiles if needed.

Fixing 20mm porcelain to compacted sub-base | Installation guide

Proper ground preparation is essential for the successful installation of stone flagstones or cobbles, and it depends on both the intended use of the paved area and the specific site conditions.

• Clearance Below Damp-Proof Course

It is crucial to ensure that the paving or cobbling is installed at least 150mm below the damp-proof course (DPC) of any building. Additionally, a gradient of 1:60 should be maintained to create a ‘fall’ that ensures water drains away from the building, preventing water ingress.

• Stabilising Layer

A stabilising layer, typically 100mm of scalping or crushed hardcore, should be laid down to create a solid foundation. This is followed by a 30-40mm sand bed, which should be compacted using a vibrating plate compactor to provide a stable base.

• Laying the Perimeter Tiles

The perimeter tiles should be bedded in wet mortar to firmly anchor them in place and prevent any potential ‘spread’ during installation. This ensures the outer edges are stable before filling in the central area.

• Bedding the Remaining Tiles

For the remaining tiles, a semi-dry or dry 4:1 sand/cement mix can be used for bedding, depending on the thickness of the stone. The right mix ensures secure adhesion to the substrate while allowing flexibility for the stone’s natural movement.

• Considerations for Stone Type and Porosity

The porosity and shade of the stone must always be considered during installation. For example, lighter-coloured stones should not be laid with a wet mix, as pigments from the cement can bleed into the stone and cause permanent stains.

• Suitable Substrate for External Stone Tiles

The prepared substrate will support exterior stone tiles of 20mm thickness or above. It is essential to verify that the material is suitable for exterior use. For thinner tiles, including many porcelain options, they can be laid on a concrete slab with adhesive and grout, following the same procedures used for internal applications. The concrete slab must be designed and installed according to relevant standards for external applications.

• Grouting and Jointing

After the tiles are fixed, the joints can be temporarily filled with sharp or pit sand, which is brushed into the dry gaps to help stabilize the tiles. However, for external natural stone installations, this method is not ideal for long-term performance, as sand alone provides minimal protection against water ingress, movement, or freeze-thaw cycles. The preferred solution is to use a suitable flexible external grout, which helps accommodates natural expansion and contraction of the stone, prevents water penetration, and significantly reduces the risk of joint failure, edge damage, or spalling over time. Using flexible grout ensures a durable, weather-resistant finish and is considered best practice for external paved areas.