He explains some of the key considerations to keep in mind and offers practical solutions.

Large format tiles and panels are a popular choice over underfloor heating systems, increasing the surface area of tiles that keep feet warm. A key requirement when cutting and installing large format tiles and panels is to manage stresses. When used with underfloor heating systems, there will be greater adverse tension affecting the tile due to thermal expansion and movement.

It is therefore important when cutting large format tiles and panels or installing them with underfloor heating systems to minimise tension and maximise strong bonding.

Cutting
Pre-drilling pilot holes at each intersection is recommended when cutting ‘L’ shaped lines around objects such as windows, doors and electric sockets. This avoids potential stress that results in noticeable micro-fractures.

Cutting shapes using only dry scribe cutting tools and angle grinders should be avoided as this creates potential stress and cracking at the intersection of cut lines.

Here’s a step-by-step guide:

1. Adapt the flat workbench to create a void for drilling holes
2. Fix the tile or panel with clamps, securing it in place
3. Start the hole by tilting the drill bit
4. Continue drilling using oscillating movement without pushing excessively, cooling the drill bit with water if necessary
5. Complete four holes (min 8mm) in each of the corners
6. Use a continuous crown disc to cut out the aperture

Adhesives and grouts
Polymer-modified cement-based adhesives and grouts should be used to withstand thermal effects. Adhesives must have a minimum C1S1 classification, conforming to BS EN 12004, while grouts will be either 1) a normal cementitious grout classified as CG1 with a suitable dispersion admix or 2) an improved cementitious grout classified as CG2, conforming to BS EN 13888.

Cementitious adhesives are also available that can be mixed to a pourable consistency to facilitate the solid bedding of large format floor tiles. These should be mixed and applied strictly in accordance with the adhesive manufacturer’s instructions.

How to apply
Solid bed fixing (including back combing of the tile) is required when fixing large format tiles and panels. When combing the back of the tile with a thin coat of adhesive ensure that any indented back profiles are filled before placing the tile in position on the adhesive bed.

Adhesives should be applied using a notched trowel with adhesive on the tile and on the substrate, flowing in the same parallel direction across the shortest width of the large format tile and panel. The advice of the adhesive manufacturer on the size and type of notched trowel should be followed.

Movement Joints
Stresses in tiles can be localised with movement joints, which is especially important to plan when using large format tiles since they are more challenging to move and position.

Large format tiles and panels require a minimum joint width of 3mm. The width and spacing of intermediate movement joints should be sufficient to accommodate anticipated movement within the floor assembly so that the stresses between the flooring and heated screed remain within acceptable limits.

The maximum area bounded by intermediate joints within the heated screed should not exceed panels of 40sqm in area for ceramic and natural stone tiles and 25sqm in area for resin agglomerate tiles. The panels formed should be square to rectangular with a length to width ratio of no more than 8x5m.

Intermediate joints through the screed and tile bed should be used to accommodate differential movement occurring either between zones of heated screed or concrete operated by separate control systems or between zones of heated and unheated screed or concrete.

Further information is available for purchase in TTA’s Technical Publications and Masterclasses.
www.tiles.org.uk

It is now a well-established trend for homeowners to maximise the outside space available to them around their homes. Surveys have shown that the usability of exterior areas ranks alongside the size of rooms and the proximity of local services as key factors influencing purchase decisions on the UK housing market. This is a trend which is also reflected in the commercial market, as the hospitality sector seeks to make the most of any external space that is available to them.

Often external areas are tiled using 20mm porcelain tiles or natural stone, which enable design themes to be created which either complement or contrast with tiled surfaces installed internally in buildings. The continuation of internal design themes to the exterior of a building is an important trend, leading to a blending of internal and external space.

There are plenty of tiles and natural stone products on today’s market, which will do an excellent job in external locations. Problems however can arise at the installation stage. Often these jobs are done by builders or keen DIYers, rather than by experienced and knowledgeable 4 tile fixers or landscapers. This can lead to problems if correct procedures (especially with regard to preparation of the substrate) are not followed.

A landscaper will take a different approach to this issue, compared to a tiler. A landscaper will not normally want to create a concrete base for laying the tiles. He or she would begin by evaluating the designated area to determine its suitability – ensuring the ground is level and free of any loose debris, vegetation, or standing water that may interfere with the installation. If necessary, the area will be excavated to a depth of around 150–200mm to create a stable base and fully remove any existing materials such as grass, soil or old paving to enable a solid foundation for the tiles. On to this a compacted Type 1 (MOT) base can be laid.

Once the sub-base is prepared and fully compacted, the next stage is to lay a permeable
bedding mortar to a suitable depth. This will allow any water or moisture pass through the installation freely and drain away.

A tiler, on the other hand, would want to work on a concrete substrate and would use a flexible adhesive, bearing in mind the maximum bed depth of the individual adhesives, using a 20mm round notched trowel to fix the 20mm porcelain tiles.

Both types of installation would require the use of a priming slurry to ensure a good bond between the tiles and the appropriate adhesive. After drying, they would be grouted in the colour and type of grout of the customer’s choosing.

Exterior installations are likely to be affected by significant environmental changes, e.g. temperature variations, freeze thaw cycles and weathering, placing greater demands on the whole assembly. Therefore, the correct design of the floor build-up and the selection of the right materials is essential to maximise longevity and performance.

It is important to ensure that any water impacting on an external tiled surface, such as rain water or melting snow, is managed. Trapped moisture at lower levels within the floor construction can create voids over an extended period as water freezes and expands. The more voids present, the greater the risk of cement-based elements becoming unstable.

Adequate drainage should be installed with appropriate falls built into the design to achieve efficient removal of surface water. Falls should always be directed away from the building, and provision for appropriate sealing and waterproofing should be made at the junction between the tiled installation and the property. Poorly constructed assemblies can lead to significant problems with both visible surface damage – such as cracking and/or debonding tiles, efflorescence and joint erosion, patchy or stained tiles and potentially unseen damage to the substrate/base. These are all indicative of excessive water residing within the assembly for longer periods of time than intended or designed for.

In certain installations, there is also a requirement for a waterproof substrate below the tile to avoid water that penetrates below the tile layer causing damage below. In the case of roof terraces situated above living accommodation additional design considerations are required. To successfully tile a roof terrace both primary and secondary waterproofing should be installed to protect the internal integrity of the building. An architect or structural engineer should be consulted for full guidance.

The correct materials should always be used, including the bedding mortars and grouts, porcelain tiles and natural stone. Porcelain tiles should be classified and marked as suitable for external use in accordance with BS EN 14411. Natural stone should be marked in accordance with BS EN 12058.

Tiles should be selected with enhanced slip resistance. This is particularly important where tiling is laid to falls to allow water to drain away from potential wet areas. In external environments, tiles may heat up and cool very quickly compared to the background. This is particularly relevant where dark coloured tiles may be exposed continuously to direct sunlight.

Joints between porcelain tiles should be grouted with a suitable proprietary grout conforming to BS EN 13888 i.e. minimum CG2 or RG type grout. Exposure to greater thermal variation and moisture movement means that intermediate movement joints should be incorporated within the tile assembly at intervals not exceeding 3 metres. Depending upon the anticipated movement in the background, the size and format of the tiles selected and the width of the tile joints, the distances between movement joints may need to be less. Movement joints, in all cases should be continuous throughout the entire assembly, as outlined by British Standards.

Consideration also needs to be given to correct cleaning regimes, in order to maintain both the aesthetic appearance and the required slip performance. External tiled or stone finishes are likely to become contaminated more quickly from dirt and debris. High pressure washing is therefore often employed. Although this will not damage the tiles themselves, it may cause damage within the grout lines so should be carried out with care. Consideration should also be given to the use of a proprietary impregnating sealer and a bespoke tile cleaner.
www.palacechemicals.co.uk

The last few years have seen a massive increase in the popularity of external tiling installations using a range of materials, but primarily external self-supported porcelain (typically 20mm porcelain), slabs, pavers and natural stone.

There are two common installation methods – monolithic fixing (i.e. traditional paving onto a mortar bed) and traditional external tiling (direct fixing onto a concrete base).

Before the Spring patio and terrace season gets into full swing, here we outline the key considerations with both methods of fixing.

Monolithic fixing
When fixing onto pre-prepared Type 1 MOT sub-base or concrete where a build-up of more than 20mm is needed than we would recommend using the traditional monolithic fixing method.

This traditional wet-on-wet fixing method is favoured most by landscapers and paving installers and involves the use of a semi-dry bedding mortar mix and a priming slurry bonding coat on the back of the tiles.

Before fixing, you must ensure that the subbase is of a suitable Type 1 MOT grade, laid to the correct depth and fully compacted.

The subbase should be stable and not liable to settlement.

It is important to note that all pavers and tiles should be free from standing or pooling water, so ensure that adequate falls are introduced to the Type 1 MOT or concrete to drain the water away to a suitable disposal point i.e. a gully, linear drain or a soakaway at the edge of the terrace of patio. Wherever possible, surface water should be directed away from any buildings.

Where the patio is adjacent to the house, particular attention should be paid to drainage, and the patio’s height must be significantly below that of any damp proof courses.

Once fully prepared, we recommend that the Type 1 MOT or concrete subbase is primed with 2-3mm of a suitable priming slurry bond coat.

A bedding mortar should then be applied wet-on-wet and then compacted down to the required height.

The bedding mortar – whether it’s a pre-mixed product or suitable sand:cement mix – should be mixed to a semi-dry consistency. Normal “free-fall” mixers aren’t normally suitable for this type of semi-dry screed mix, so consider the use of a forced-action mixer.

The amount of mortar mixed and the area to be screeded should be limited so that trowelling off, finishing and tile fixing can be completed within the working time.

Where a new bay is laid against a set and hardened mortar bed, it is recommended that such daywork joints are vertical and treated with a priming slurry bond, with the bedding mortar applied onto the wet slurry.

On Type 1 MOT sub-bases, bedding mortar should be applied as required from min. 25mm to max. 100mm thicknesses, while on concrete substrates, a bedding mortar can be applied as required from min. 10mm to max. 100mm thicknesses.

To fix an external porcelain tile, paver, slab or natural stone, while the bedding mortar is still wet, apply another coat of priming slurry coat at 2-3mm on top of the bedding mortar, as well as a thin coat to the back of the tile or paver to ensure 100% coverage is achieved.

This step is critical, as bedding mortar on its own will not naturally adhere to porcelain pavers. The priming slurry acts as the “bond-bridge” between the low-absorbent porcelain tile and the mortar bed.

Once in place, the tile or paver can be adjusted and then firmly bedded with rubber mallet.
With fast setting pre-mixed mortars, grouting can commence in as little as 12 hours. With a hand-mixed sand:cement mortar mix this can be anything from 24-48 hours – significantly extending project timescales.

When using traditional OPC (Ordinary Portland Cement) and sharp sand mixes, consideration must also be given the quality of sand along with its potential water content, as well as the prolonged set times associated with standard Portland cement formulas.

We would recommend the use of a cementitious grout that is suitable for external use.
However, consider the use of a hard-wearing, chemically resistant and durable epoxy grout system for driveways and eating areas for example.

Traditional external tiling to concrete
This method is most suited when fixing porcelain, pavers, slabs or natural stone (suitable for external use) direct to an existing concrete base.

This direct fixing method is essentially the same as internal tiling and can be used for patios, terraces or driveways.

The caveat being that the concrete must cure for a minimum of 6 weeks, expansion joints may need to be incorporated, and falls will need to be added to ensure rainwater drains away fully. An effective DPM should also be incorporated into any direct-to-earth subfloors – this is essential to protect the tiles from any subfloor moisture.

However, these installs also mean that 20mm (self-supporting tiles) are not a requirement. Porcelain of any thickness may be installed, as long as permitted for external use by the manufacturer. Which means potential reduced tile cost with easier handling and cutting.

Before direct fixing, the concrete base must be fully cured and free from efflorescence, laitance, dirt, polished concrete and other loose materials. These should be removed using suitable mechanical methods or even removed using high pressure jet washing. Some exposed aggregate should be visible in the surface but not loose.

No need for priming, simply dampen the surface with water, taking care not to leave any pools, before applying your tiling solution.

Where necessary, you can smooth the surface with an external levelling/smoothing compound. It is important to use any compound in accordance with the manufacturers instruction which can usually be found on the packaging. For isolated repairs, external repair mortars may also be considered.

If a levelling/smoothing compound is used, then protect this from adverse climatic conditions, e.g. rapid drying air flow, direct strong sunlight, rain, frost etc., until hardened.

Once the concrete is suitably prepared, external tiles, slabs, pavers or natural stone can be fixed using a suitable external tile adhesive. Your selection may be based on weather considerations, and of course may also be impacted on with the tile or stone type and size too.

Some external tile adhesives can be used directly onto tamped concrete without the need to pre-smooth – this may be an option if there are time or budget constraints, but choose your adhesives correctly, as not all can be “built up”.

Back-buttering of the tiles should always be considered – particularly on heavily keyed tiles to ensure 100% adhesive contact.

Solid-bed fixing of the tile is critical (as per British Standards) and failure to do so, can lead to costly failure, efflorescence etc.

Once the adhesive has cured, grouting can commence with an appropriate cementitious grout which is approved for external use.

Again, consider whether an epoxy grout maybe more suitable – for example food preparation areas or areas of high traffic such as driveways.

The ARDEX Group has services to support installers including a nationwide team of training and technical support managers, plus technical advisors available on the phone or on-line for our brands.
01440 714939
info@ardex.co.uk

If you are working in a warm environment, in someone’s house for example, the primer will dry fairly quickly – about half an hour. When I am on-site, I get the primer down straight away and use the drying time to get all my tools and products ready so I can get on to the next stage of the job straight away.

Fast-track levellers will speed up the job even more! Using a rapid setting floor leveller, such as ProLevel Rapid will allow you to start fixing tiles after just 45 minutes – the perfect amount of time to get the kettle on and get your tiles and adhesive ready.

But if we are talking about fast-track tiling why bother levelling at all? The reason is simple. Smoother subfloors are easier and quicker to tile than rough and bumpy floors. It is always best to add this step in, as it will absolutely save you time later – a worthwhile step for sure!

When it comes to selecting your adhesive, it is good to understand the difference between slow set and rapid setting products. A lot of tilers tend to prefer slower setting adhesives as the pot life is longer, however, an adhesive like ProFlex SP will still give you a generous pot life of 60 minutes, allowing you to cover a fair amount of space, but with the additional benefit of a set time of just 2.5 hours.

So now it all comes down to the final step – grouting! Whilst this stage needs to be executed carefully for a beautiful finish, it doesn’t mean the grout has to take all day to set. Grout with ProGrout Flexible and your job will be finished in no time at all.

Follow these simple steps and you can prime, level, fix and grout tiles, all in one day!

I hope you found this article interesting and it helps speed up your next job. As always, if you would like any advice on an upcoming project, please get in touch and I will be more than happy to help. You can message me on Facebook or LinkedIn or call +441827 254402.
www.instarmac.com.uk

While traditional sand:cement screeds still account for the majority of the screed market, flowing anhydrite (gypsum) screeds, which were originally introduced about 35 years ago, now account for perhaps around 20%. This is not as large a proportion as some in the early days of their use thought they would account for – in some European countries their market presence is three or four times greater. The reason for this is probably due to factors such as the extended drying times they require, (due to UK climatic conditions) and also the inherent incompatibility that exists when anhydrite screeds come into contact with cement-based adhesives.

Anhydrite levelling screeds are based on a calcium sulphate binder and should never be used when directly overlaying with ceramic tiles or mosaics fixed with cementitious adhesives.

They should first be fully dried to 75%RH (0.5% w/w carbide test); abraded to remove laitance and efflorescence and then completely sealed with an effective and proven primer, so as to prevent the adhesive from coming into direct contact with the calcium sulphate in the levelling screed, which is likely to result in the formation of “ettringite” expansive salts at this interface.

So why use them? They do offer a number of benefits over sand:cement screeds. The main advantage is that they can be laid more quickly and easily as they can be more readily pumped and are more cost effective, especially for larger areas. They can be manufactured from industrial by-products and so provide an environmentally friendly “low carbon” alternative to conventional cement screeds.

They also cure with minimal shrinkage, which makes them especially suitable for deep-bed applications where they are used with underfloor heating systems and can fully encapsulate all pipework. Up to 2,000sqm of anhydrite screed can be laid in a single day – compared to 100-150sqm which is the maximum possible with conventional sand:cement screeds, making them particularly suitable for use on large commercial contracts.

However, to achieve the required maximum relative humidity of 75% (or 0.5% w/w) prior to tiling, the relevant British Standard (BS8204-7:2003) states that the minimum required drying time for anhydrite screeds is one day for each mm of thickness for the first 40 mm, plus a further two days for each mm over 40 mm thickness. It is reasonable to expect a screed over 50 mm thick, drying under room temperature conditions (at 20°C < 65% RH) to be sufficiently dry within about two months and be ready to receive a tiled finish, subject to primer and sealer recommendations.

Failure to follow these recommendations and tiling before the screed is sufficiently dry may result in adhesion failure at the screed/adhesive interface.

Whilst there is a range of effective priming and sealing products that can form an effective barrier between anhydrite floor screeds and over-laid cement-based products, they still require the full drying period referred to above to reach the requirement of a 75% RH moisture reading in the anhydrite screed base.

The speed of drying can be improved by increasing the ventilation in the room or by using a temporary external heat source, such as a space heater, which are even more effective when combined with the use of industrial dehumidifiers to physically reduce the level of water vapour in the room and hence promote drying of the anhydrite floor screed. Finally, where sub-floor heating is installed, it can help to gradually activate this incrementally after just 7 days to further purge moisture from within the screed.

Regular monitoring of the effectiveness of the drying process is advised by conducting regular tests of the floor’s moisture content, either using a surface hygrometer (testing relative humidity to a target of 75% RH) or a carbide bomb mechanism (the target being 0.5% water by weight), to determine when the moisture target has been reached and the next layer can be applied.

A further issue with anhydrite floor screeds as they dry out is the appearance of surface laitance, a dusty friable deposit which should be cleaned and removed from the surface by light abrasion using a suitable sanding machine as soon as seven days after being laid, as this can assist the drying process. Remove any excess dust this creates with a vacuum cleaner and when the target moisture content has been reached, the surface must be abraded and scarified again to remove laitance and any surface contamination before preparing for a tiled or decorative finish.

When the anhydrite floor is dry and the surface prepared as above, the application of a “primer sealer” coat is a final and essential step before tiling over with a cement-based adhesive. The application of two coats of SBR (or acrylic) based tiler’s primer 4
is needed, the first being diluted one to one with water and the second coat applied neat.

This method has been proven to be an effective way of creating an impermeable boundary between the anhydrite screed and the cement-based adhesive which prevents the risk of any adverse reaction between the two materials which may result in the creation of ettringite, an expansive salt which can lift tiles from the anhydrite surface if the primer sealer barrier has not been effectively applied.

Other barrier coatings are also available, including liquid waterproof membrane systems and matting laid over the anhydrite screed and all are effective in preventing contact between cement and the gypsum-based anhydrite sub-floor.

More complex surface sealing systems such as Palace Pro-Gyp Base now offer a 4-component solution, where two coats of epoxy primer are applied and over-coated with a moisture suppressant coating and finally an aggregated sealing top-coat, all of which combine to create an impermeable barrier, which is effective where the moisture content of the anhydrite screed is significantly higher than the traditional 75% RH target, (up to 95% RH after 7 days!) allowing for earlier application of tiled finishes fixed with cement based adhesives.
www.palacechemicals.co.uk

These surfaces – and the grouting and sealant between tiles – provide an anchoring point for microbes, leading to staining, odours and degradation. Kimberley Cherrington, senior manager, global brand & marketing communications, explains one way to combat these microbes.

The challenge of microbial growth
Routine cleaning helps to keep microbial loads down, but often to little avail, as the limited residual activity of conventional disinfectants allows surfaces to become contaminated again very quickly. With microbes capable of doubling every 20 minutes, it’s near impossible for users to wipe surfaces frequently enough to maintain cleanliness. In addition, harsh cleaning chemicals and excessive scrubbing can also impact the integrity and aesthetic of tiled surfaces. Combined with the staining, odours and degradation from microbial growth, this reduces the usable lifetime of ceramics and increases user frustration, often resulting in the premature disposal of products. It is therefore unsurprising that ceramic materials constitute the largest volume of construction waste during the refurbishment of residential buildings, as they are regularly replaced. This is driving the demand for antimicrobial solutions that can keep surfaces cleaner for longer, promoting more durable and sustainable choices.

Built-in antimicrobials
Built-in antimicrobial solutions can be integrated into ceramic glazes during the manufacture of tiles, where they can interact with microbes to disrupt their metabolism, inhibiting their growth and survival. Once incorporated, the technology becomes an integral part of the material that does not wash off or wear away. This provides around-the-clock product protection against the growth of microorganisms, and works with existing cleaning routines to help prevent staining, odours and early product deterioration. Users can therefore feel reassured that surfaces are not only cleaner, but will also last longer, extending the time to the next refurbishment and reducing construction waste. More durable products such as this are helping to reduce the mountains of discarded waste that pollute our landfills and oceans for a more sustainable future.

The topic of sustainability is also shaping the future of the antimicrobial industry, as leaders in the field are shifting toward more environmentally friendly options. Microban International recently launched a series of innovative, non-heavy-metal antimicrobial and odour-control solutions, reflecting its corporate focus on developing more sustainable technologies.

Summary
Consumers and manufacturers alike are more concerned about sustainability than ever before. Waste management is an area that needs a significant amount of attention in the construction industry, and more durable, long-lasting products can help to reduce our impact on the planet. Working with knowledgeable antimicrobial suppliers that have a wealth of in-house ceramics expertise – together with years of industry experience – is the key to delivering a product offering enhanced cleanliness and sustainability.
www.microban.com

Movement stress can build up in a heated floor during the heating and cooling cycles. Therefore, it’s important that the coefficient of thermal expansion of the rigid tiled finish does not vary too much from the heated sub-floor.

This is because small changes in expansion and contraction exert greater stresses on rigid tile finishes. In addition, to reduce the risks of tiles cracking or de-bonding, adequate preparation and, where applicable, commissioning of the floor heating system is crucial – as is the correct selection of adhesive and grout. Here we list the essential preparation for each type of system:

Hot water pipe system (in screed)
If tiling onto a hot water pipe system, ensure the screed has fully dried. In the case of reinforced cement; sand based screeds; this ranges from 6 days with a quickset screed, to a minimum of three weeks for a screed containing OPC. Following this period of curing, the screed may be commissioned by heating slowly at a maximum rate of 5°C per day up to the maximum operating temperature as recommended by the heating manufacturer. The temperature of the screed should be maintained at this level for a minimum of three days, before allowing it to cool to room temperature.

For anhydrite or alpha hemihydrate calcium sulphate screeds, surface preparation is also critically important. The drying times are dependent upon the thickness of screed and could be extended further, dependent upon site conditions. Further guidance may be sought from our technical department or the screed manufacturer.

Again, commissioning of the screed should be carried out in accordance with the heating manufacturer. The heating may also help with increasing the drying rate of the screed.
Ensure that the heating system has been turned off, or on in cold temperatures, to ensure the screed is at 15°C before tiling commences.

Overlay/ retrofit systems
There are also numerous overlay or retrofit systems on the market which require unique preparation and can vary in installation from manufacturer to manufacturer. ARDEX Group products and systems can be used for some overlay systems – please contact our technical department for advice and recommendations.

Electric Cable systems
When using cable systems check with the manufacturer to ensure the system is compatible with the intended substrate and application areas i.e., kitchen, bathroom etc.
Backgrounds may require priming. The cables should ideally be encapsulated in a layer of a suitable fibre-reinforced self-smoothing levelling compound. When using an uncoupling system, the heating cables should be below the uncoupling membrane.

Heating carrier mats
Again, check with the manufacturer that the chosen system is compatible with the substrate and to the environment it is being used in. Backgrounds may require priming before the installation and application of subsequent levelling compounds or tile adhesives.

Movement joints
Movement joints should be incorporated at all perimeters of the screed, including upstands, door thresholds between separate areas of use or anything which penetrates the screed, such as columns or pillars. Usually formed whilst the screed is being laid, movement control joints should penetrate the full depth of the screed to the insulation layer.

Once tiling commences, movement joints should be incorporated to coincide with those in the screed. For floors subject to thermal changes, such as underfloor heating, floor areas should be divided up by movement joints into bays of size, not greater than 40sqm for ceramic and natural stone with an edge length of not greater than 8m.

Movement joints should also be located at the junction between heated and unheated screed sections.

Further advice should be sought from BS 5385: Part 3, the code of practice for internal and external ceramic floor tiling and The Tile Association’s technical document Tiling to Heated Floors.

If using an uncoupling mat – which we would always recommend with an underfloor heating system – the mat should be separated where intermediate movement joints are located.

Suitable adhesives and grout
When tiling onto underfloor heating 4 systems ensure that you use a suitable flexible polymer modified tile adhesive – to allow for natural thermal movement in the floor. We have a number of adhesives in the ARDEX Group which are suitable for underfloor heating.

As with your adhesive choice, your chosen grout should also be flexible to allow for thermal movement.

We would also recommend you contact our technical department or training and technical team for advice before any work is carried out!
www.ARDEX.co.uk
www.BAL-Adhesives.co.uk

A large tile is generally considered as anything greater than 30x30cm. Large tiles are perfect for stylish, minimalist designs as they contain fewer grout lines, creating a more seamless look. They are naturally great in large rooms and open-living plans but can also be used in smaller rooms to give the impression of more space.

Surface preparation
Given their size and weight, large tiles can be difficult to handle and should be applied by a skilled and experienced tiler. If they are not installed properly, damage can occur which can be costly to rectify.

To achieve optimum results, having a level floor is key. Large tiles are less forgiving compared to smaller tiles and are more at risk of breakage if they are not on a level floor. If necessary, a floor screed can be used to provide a flat surface to be tiled upon.

The next step is to prime the surface to regulate the porosity and ensure adequate adhesion. Always refer to the manufacturer’s instructions to ensure the correct dilution for the substrate. Once you have the correct ratio of water to primer, apply to the surface and brush in. It’s important to wait the required time for it to dry and reapply if needed.

Tiling tips
It’s always good practice to check the boxes of tiles for quality and shade and mix the boxes to create a good blend of colour and pattern. Remember to inspect each tile for damage or excessive bowing.

When mixing the tile adhesive, refer to the instructions provided and measure the correct water to be added or mix by volume. A flexible tile adhesive is recommended for large format flooring tiles so it can withstand the associated movement from foot traffic.

Apply the adhesive to the primed floor and use a notched trowel to create a ribbed adhesive layer. Butter the back of the tile before fixing, this will aid adhesion and reduce dust. Use a rubber mallet to then tap the tile down to help bed it into the adhesive.

It is advisable to lift the occasional tile to check the coverage of adhesive and ensure the tile is fully bedded. Visible ribs in the adhesive would indicate a lack of coverage while good coverage is indicated by peaks forming in the adhesive. If required, add more adhesive to ensure full coverage. It is more awkward to rectify larger tiles, so it’s wise to apply a good initial coverage of adhesive to avoid rework. To help provide a level finish, use a tile levelling system during installation.

The finishing touch
When the tiles have been laid, grout and silicone will then need to be applied. Mix the grout mechanically to form a smooth paste and don’t re-wet or put too much water in the mixture.

Apply the grout liberally with a grout float and smooth into the joints. When the grout is firmly in the joints and after about 15-30 minutes, clean the tiles being careful to not use an excessive amount of water. Applying a silicone sealant around the edges will finish the job perfectly.

While large format tiles can cost more compared to regular sized tiles, if applied correctly they can really give a room the “wow factor”.
www.uk.weber/tile-fixing

There are many enjoyable things about winter – Bonfire Night, Christmas and New Year to name a few, but working in the cold weather is another matter entirely. During the winter months, we are often asked if it is OK to work in freezing temperatures so we thought we would answer out most commonly asked questions.

Should we work in cold temperatures?
Theoretically, the answer would be no. However, we know that isn’t practical or possible and work still needs to be carried out in the winter months. Closing your business for a few months of the year isn’t feasible, money needs to be earned and jobs completed. With that in mind, there are a number of things we can do to make working in winter much easier.

When does “no” mean “no”?
No means no when the temperature will not be 5°C above the dew point throughout application and curing. This is to ensure there is no moisture present at the subfloor surface which will hinder adhesion. Dew point is linked to atmospheric humidity and temperature.

What can go wrong when working in cold temperatures?
As you know, most adhesives are cement-based and cement cures through hydration. Cold temperatures will affect the moisture content in a cement-based product, and so, if we work in cold conditions, you might find that the cement does not set or could even freeze.

It’s also worth noting that curing is an exothermic process which needs heat to start the chemical reaction. If the air temperature is too low, there will not be enough heat generated to cure the product, which will prolong the set – not ideal!

That being said, there are things we can do to make working in cold temperatures more manageable. Which brings us nicely on to the next question.

If you do have to work in cold temperatures, what can help?
Our first tip would be to store all your products inside, ideally in a heated environment. Please do not store products in your van or outside. This will dramatically reduce the temperature of the product making your job so much harder before you even begin.

The same goes for storing tiles. Tiles can be cold at the best of times so storing them outside is a real no go during the colder months. Storing your tiles inside will make a huge difference to your installation.

Air temperature is also a big one! Where possible, raise the air temperature within the room to give you a more ambient working environment. We recommend using a heater rather than a gas burner to prevent condensation.

In the same way we recommend using cold water for mixing in the summer months, during the winter we advise using water that is above 20°C for mixing. This will minimise the risk of prolonged set and/or the product failing to set at all.

If you are working on a substrate that has underfloor heating within it, you can turn the system on to 15°C to help raise the temperature. Remember, you need to maintain this temperature for 7 days.

These are our top tips for working in the colder months. We would love to hear what your tips are for working in the winter. Join the conversation by following #UltraTileTips.

I hope you found this article helpful. If you need any support with your tile installation, you can call 01827 254402 or connect and send me a message on LinkedIn.
www.instarmac.co.uk

For large format tiles, with a surface area >3,600sqcm (with no tile edge >1,200mm) the first thing to be mindful of is the placement of ceramic tiles, leaving adequate joint widths between the tiles. Joints between ceramic wall tiles should be at least 2mm wide. British Standards advises for large format tiles, a minimum joint width of 3mm is required. In the case of ceramic panels, the joint width should be increased pro-rata to the size of the panel. Butt-jointing tiles is not advised.

The joint widths between tiles should take into account the type, size and permissible dimensional tolerances of the tiles. A grout must also be chosen which is suitable for the expected use of the tiling whilst in service.

The second thing to be mindful of is the selection of the correct adhesive for the type and size of ceramic tile to be installed – especially large format tiles and ceramic panels. For the installation of large format porcelain tiles, use a suitable improved cementitious, highly polymer-modified tile adhesive

Also, it would be advantageous to use tile adhesives with additional properties of extended open time, and reduced slip resistant properties (for wall tiling with larger wall tiles). The need for solid bed fixing is a must, as poor contact will potentially lead to tiles cracking and/or debonding. Do not spot fix ceramic tiles with tile adhesive.

Tiles should be solidly supported by the tile adhesive. Air pockets or voids beneath the tiles are potential points of weakness due to an impact from a heavy object. Tile adhesive should always be applied to the wall using a suitable notched trowel as per the adhesive manufacturer’s recommendations. In addition, back butter large format tiles by applying a thin bed of adhesive on the back of the tiles to fill in any deep keys or heavily buttoned back tile profiles before placing into the adhesive ribs, applied using the correct notched trowel to the wall.

However, when using some pourable tile adhesives, back-buttering may not be required – as long as the surface is level and flat. Occasionally lift a tile to check adhesive contact to check for any voids beneath the tiles.

You should also be mindful of preparing the background i.e. pre-levelling of the floor or wall as per the adhesive manufacturer’s recommendations prior to using the tile adhesive. This will help ensure you have a flat surface to tile and help ensure solid bed fixing is achieved.
There are a number of options for floor levelling from all-rounders, to fast levellers. Ensure you choose the right levelling compound for your application.

Be aware that some levelling compounds may take longer to dry than anticipated, so use a trusted product with the technology to dry as stated on packaging and technical datasheets. Always check those technical datasheets for accurate mixing instructions and curing times!

Adhesive and levelling manufacturers like the ARDEX Group UK have to continuously develop our products to suit new types and sizes of tiles. Adhesives developed 15 years ago were developed with a lot of different types of tiles in the marketplace. New products are developed for the tiles in the marketplace today.

Be mindful of this when choosing the right adhesive for the tile being installed.
www.ardex.co.uk