Frequently Asked Questions (FAQ's) ...

Do you have a question about tiles or tiling that Super Ceramic Services Ltd might be able to answer? Please take a look below to see if your question is there before Contacting Us to ask a question. We believe that around 50% of all the telephone queries we receive can be answered in the FAQ's below!

How slippery are tiles? - There are several different ways of testing the slip resistance of floor tiles, and tile suppliers should be able to advise the slip factor of tiles that they stock. It is important to chose the right floor tile for your project, for instance a wet area such as a swimming pool surround or shower area requires a higher degree of slip resistance than a dry area.

Where can I find and purchase discontinued tiles? - If you have a sample tile maybe Super Ceramic Services Ltd will be able to help find the original manufacturer and see if they have any stock left. If that fails we can hopefully offer a suitable alternative from our vast range of stock items.

Can tile make a small room look larger? - Yes, larger tiles give a cleaner look and can actually make a small area look larger. Depending on the room's size, a 12 inch or 13 inch tile will create the illusion of a larger room.

What different types of tiles are there? -

• Natural stone products; limestone, marble, granite and slate are quarried from the earth. Some are extremely hard, and some quite soft. Some may need sealing.

• Unglazed ceramic floor tiles are more suited to commercial and industrial settings, but can be used in laundries and utility rooms. They are available with a non-slip profile.

• Ceramic tiles can be glazed or unglazed. Glazed tiles are available plain or decorated and can be used on walls and floors.

• Quarry tiles are a traditional product made in the UK for hundreds of year. They are made from natural clay, squeezed through an extruding machine, and then fired. They are mostly available in terracotta, black and white colours.

• Terracotta tiles are also made from local clays. Terracotta means "cooked earth" and these products tend to be very absorbent, so need sealing when used on the floor.

• Porcelain tiles are ceramic tiles, but with a very low absorbency. They are usually made from kaolin clays, feldspar, silica and colouring oxides and are fired at about 1200oC. Porcelain tiles are hard wearing and can be used on walls or floors.

• Mosaics are very small tiles, usually less than 35cm2. Mosaics can be glazed or unglazed and made from porcelain, ceramic, glass or natural stone.

What is glaze? - To give tiles colour and design a coating, known as a glaze, consisting of ground glass and colour pigments are fused onto the clay surface through intense heat in a kiln.

What is travertine? - It may be apt at the beginning to describe travertine limestone's in general. The name originates from the Italian 'travertino' and was originally a stone quarried in central Italy and used extensively by the Romans. Today they are quarried in many areas of the world. Travertine is calcite (calcium carbonate) deposited from solution and is, quite literally, full of holes.

Travertine stones are characterised by an amount of voids within the body of the stone and, as a result of this, they have very low density and compressive strength and this applies even to the high quality classical travertine's. Although the faces are filled, usually with synthetic resin filler, there are always other voids just below the surface and these will eventually show as the floor wears, or the surface breaks down and voids appear. This is a characteristic of travertine's and should be expected to some degree. Travertine is usually used internally, both for domestic and commercial use.

For best practice, fixing travertine please use British Standard BS5385 as the code of practice for fixing wall and floor tiles. Part 5 of the Standard refers to the fixing of natural stones. Solid bed fixing is important, as a heavily voided tile will collapse more readily if there is no support from below.

What is the best way to fix tiles to a wall or floor? - Full guidance is given in British Standard, BS5385 Wall and floor tiling. The following points should be remembered:

Background

• The ideal background is cement:sand rendering

• Weight restrictions for tiling onto plaster and plasterboard are defined in BS5385:1, i.e. 32 kg/m2on plasterboard, and 20 kg/m2 on plaster

• The background to receive tiling should be fully cured, dry, clean, sound and nominally flat, such that when checked using a 2m straightedge, any gap under the straightedge should not exceed 3mm.

NOTE: Larger format tiles with a surface area greater than 0.1m2 may need additional mechanical fixing when used above 3 metres.

Setting Out

Vitrified and porcelain bodied tiles are often polished for aesthetic purposes. The polishing process, which involves grinding, will reduce the thickness of the tiles and possibly the overall dimensions of the tile. Therefore extra care should be taken at the design stage and during installation.

• Tiles should not be butt jointed

• Pressed tiles should be spaced at a minimum of 3mm

• Extruded tiles should be spaced at a minimum of 5mm

• Rectified or calibrated tiles should be spaced at a minimum of 2mm

Fixing

• Lighting during tile fixing should be as close to the end use as possible

• Tolerances for surface flatness are defined in BS5385

• In a dry area a minimum area of contact of 75% should be achieved

• In wet areas solid bed fixing is required

Adhesives and Grouts

• Use a polymer enhanced adhesive meeting the requirements for a cementitious Class

• C2 adhesive defined in BS EN 12004

• Grout meeting the requirements of BS EN 13888 should be applied as defined in BS5385

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

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

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

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

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

Is it possible to tile over existing tiles? - Yes, providing that the existing tiling is firmly bonded to the existing background. You will have to clean the existing tiling thoroughly and degrease them before fixing the new tiles.

Make sure that you buy the correct adhesive when tiling over existing tiling, so please do not forget to ask us when you buy the adhesive what you are planning to do with it.

What is the best way to cut shapes in ceramic floor and wall tiles? - When working with wall and floor tiles it is important to wear safety gloves and goggles. Wall and floor tiles can be very sharp when cut or trimmed.

Cutting tiles with a scribe

Mark the tile to be cut and then place it face up on a firm surface. Using a metal ruler scribe a straight line into the tile using a tile scriber. Place a support under each end of the tile and press down firmly. The tile should break cleanly.

Using hand tile cutters

Mark the tile to be cut using a tile marker supplied with the hand tool. Place the tile between the jaws of the cutter and apply pressure.

Cutting shapes

It is well worth while spending a little time when cutting shapes into a tile. Firstly draw up a template of the tile to be cut. When using a tile nipper you should aim to cut a small piece at a time, as trying to cut too much at one time may lead to the tile breaking.

Begin by cutting in from the edge of the tile and work towards the lines you have marked. As you get closer to any corners that need to be cut work from the outside of the tile towards the corner. Clean out the corner carefully, using a tile file if necessary.

Drilling

Before starting you should stick masking tape onto the tile. This should stop the drill slipping. Specialist diamond tipped drill bits are readily available for drilling hard format tiles.

For some porcelain tiles a wet drill stand using a diamond core bit with the tile fully supported on a flat piece of board will be necessary. The drill must be on a slow speed. Some tile suppliers may offer this service. On occasions it is possible to cut holes by "stitch" drilling, i.e. cutting a series of holes close together in the area which will be waste. A few more holes would then be cut until it is weak enough to break out the hole. Once this has been done, the edge of the hole should be filed using a round file.

Tiling Tools

There is a wide range of powered cutting tools available on the market aimed both at the DIY and contract sector. It is important to follow the manufacturer's instructions when using these tools.

What should I consider when thinking about the joints between tiles? -

It is important to have a joint between tiles to allow for movement in the structure. It is also important that tiles do not butt against one another. Where tiles are in contact with each other, this will increase further the effects of any stress built up within the tiling layer where movement exists or may be anticipated.

Leaving a suitable width of joint between tiles and filling these joints with a suitable grouting material enables localised stress relief to occur and when combined with the use of adequate movement joints, will reduce the risks of any problems occurring.

The width of joint can vary depending on your tiling project. A 6mm joint may be used on a floor, whilst a narrower joint of say 3mm may be used on a wall. Super Ceramic Services Ltd will be able to discuss this before tiling work begins.

The British Standard for tile fixing, BS5385, suggests the following tolerances on finished work.

Flatness and variation from plumb:

• ± 3mm under a 2m straightedge

Variation across Joints:

• ±1mm for joints less than 6mm wide

• ±2mm for joint 6mm or more wide

Grouts effectively fill the voids between ceramic or natural stone tiles, preventing debris such as water, dirt, dust, debris from filling the gap. The choice of grouting materials will depend on the width of the joints and the service conditions of the floor or wall. Super Ceramic Services Ltd will be able to help you chose the correct grout for your tiling project.

The joints between tiles should be clean and free from loose material before grouting. Sufficient time should elapse after fixing so as not to disturb the security of the tiles during grouting. If you use a proprietary grout use it in accordance with the manufacturer's instructions.

The grout should be applied over an area that can be worked within the open time of the material used, working the grout into the joints with a rubber squeegee or grouting trowel, ensuring that the joints are completely filled.

Remove the surplus grout from the face of the tiles and allow to set. Clean off tile surface with a damp cloth or sponge. Wide joints may require tooling to provide a dense surface to the joint. Polish tiles with a dry cloth once the grout has set. Joints in floor tiling should be finished as near as is practicable flush with the tile whereas joints in wall tiling can be slightly recessed.

What is the best way to tile onto Gypsum Plaster? - When fixing ceramic wall tiles to gypsum plaster surfaces on masonry backgrounds you should keep the following points in mind:

Although ceramic tiles can be fixed to a wide variety of backgrounds with appropriate adhesives, most tiling is fixed onto cement-sand rendering, gypsum plaster systems or onto plasterboard.

Cement-sand rendering is the preferred background for tiling and detailed guidance is provided in British Standard Code of Practice BS5385 Wall Tiling (BS5385-1, BS5385-2 and BS5385-4). Less information is provided about gypsum plaster backgrounds and this joint statement has been prepared in order to emphasise the conditions under which gypsum plaster can be safely used as a suitable background for ceramic tiles.

It is very important that the masonry background is thoroughly dry. A minimum of six weeks should have been allowed between the construction of the masonry background and plastering. The presence of moisture in the background will not always be visually evident.

This is particularly important where gypsum plastering is to be applied onto concrete walls especially if of lightweight or aircrete (aerated concrete) blocks or onto insitu concrete walls or onto cement-sand rendering.

Caution: Cement-sand rendering dries gradually with shrinkage taking place. If a cement-sand undercoat is not cured and dried prior to plastering and tiling, the subsequent drying shrinkage of the rendering can break the adhesion between the undercoat and finish coat of gypsum or between the finish and tile adhesive causing failure. New concrete walls require a longer drying time to allow shrinkage to take place, otherwise similar problems will occur. The same is true of existing concrete walls which have become saturated in use.

If plastered or rendered walls are to be tiled, this should be decided in advance of plastering, and should be given as a separate item in the Bill of Quantities and contract specification. See item 19.

Plastering should be done in accordance with the recommendations given in BS5492 and modified in BS 5385-1 section 3.4. The plasterwork should be firmly adhered to its background and be sufficiently strong to support the specified tiling.

The maximum weight of tiling which can be supported by a dry, well-adhered plaster background is 20kg/m2, generally equivalent to ceramic tiles with a thickness of 8mm or natural stone tiles with a thickness of 7mm. When fixing directly to unskimmed paper-faced plasterboard surfaces the maximum permissible weight is increased to 32 kg/m2. These weights include adhesive and grout.

Proprietary gypsum based systems are recommended because both the undercoat and finish are designed to work together. Advice on which finish coats work with which undercoats is available from the manufacturers.

Gypsum plaster must be thoroughly dry before tiling. New plasterwork consisting of undercoat and finish coat should have been completed at least 4 weeks before tiling is commenced. Tiles should never be fixed to plaster which is not dry throughout. Where drying is assisted by space heating or dehumidifying, care should be taken to ensure that the plaster is not just dry at the surface. The heater or dehumidifier must not be directed at the plasterwork.

It is important to understand that some gypsum plasters may appear dry on the surface whilst still containing moisture within.

Use of non-invasive radio frequency moisture meters will be of help in determining moisture levels still within rendering/plastering and/or the background.

When it is known in advance that tiles are to be fixed to a plastered wall, it is essential that there should be good adhesion between the undercoat and the plaster finish coat. Tiles should only be fixed to the finish coat and must not be fixed directly to a gypsum undercoat.

The finish plaster should be specified and applied to provide a matt finish. Excessive trowelling of the plaster to ‘improve’ its appearance must be discouraged, since this practice may result in a dusty or shiny surface which is not suitable for tiling. If the finish plaster is hard and sound but has dusty or friable residues on its surface, the surface should be thoroughly brushed down. If trowelling of the surface has produced a shiny and smooth surface, this must be removed by vigorous brushing. Where the use of a primer is recommended before the tiles are fixed the recommended primer should be applied strictly in accordance with the manufacturer’s instructions.

Every plaster surface should be examined carefully by the tile fixer before any tiling work is undertaken, paying particular attention to surface finish. In addition, it is important to sound the whole area carefully for any evidence of hollowness or lack of complete adhesion in the backing. Any such defects must be remedied by cutting out and replastering before tiling. The repair must also be allowed to fully dry out.

On old plastered surfaces any decaying or loose areas must be cut out and made good.

Sometime painted plaster surfaces are encountered. Hard gloss paint if well bonded is usually a satisfactory base for tiling, but any paint showing signs of flaking should be removed. Emulsion paint or distempers can break down after tiling and must be removed mechanically prior to tiling. The surface to receive the tiles must be clean, sound and dry.

Since thin-bed adhesives not exceeding 3mm bed thickness are generally specified for fixing tiles to plaster, the plaster surface should be plumb, true and level. Trueness of surface should be such that when checked with a 2m straightedge, any gap between points of contact should not exceed 3mm.

Note: However such close tolerances of the trueness of a plastered surface will not have been attained unless the surface was specified to be tiled prior to plastering and the appropriate specification for plasterwork defined. Explanation a plastered surface, which is not to be tiled, is not required to meet such tolerances.

Generally, ready mixed adhesives conforming to Types D1 or D2 of BS EN 12004 are appropriate for fixing ceramic tiles to properly prepared plaster backgrounds.

Where fully vitrified large format tiles (under 20kg/m2) are to be fixed the recommendations from the adhesive manufacturer regarding adhesive and surface preparation should be sought.

Plaster is not a satisfactory base for tiling in wet areas e.g. shower compartments. Reference should be made to BS5385-4 for tiling in wet areas. If the backing consists of existing gypsum plaster seek the adhesive manufacturers advice on suitable waterproofing systems.

Super Ceramic Services Ltd wishes to acknowledge the assistance provided by The Tile Association, British Gypsum and the Federation of Plastering and Drywall Contractors in the drafting of this advice note.

Footnote. This paper deals with tiling onto internal plastered surfaces. Those made with ‘gypsum plaster’ are often simply referred to as ‘plaster’ whereas those made with a ‘cement based plaster’ are referred to as a ‘cement-sand render’.

Is there a product available that will colour my grout to another colour? - No not really. The use of light coloured grouts on floors is certainly unwise as the most frequently trafficked areas and/or highest spillage areas will always darken first, leading to a patchy overall appearance. It is advisable to use a dark grout such as grey for floor tiling. The best thing to do would be to remove the grout with a grout rake. This needs a steady hand as it is easy to damage the edge of the tiles. You can hire an electric grout rake but take care as some slates are quite soft.

Once the joints have been re-grouted with a suitable colour the floor should be thoroughly cleaned and allowed to dry. It will then be possible to seal the floor fully with a suitable impregnating sealer which will prevent the grout from staining in the future. Alternatively you can clean the grout and colour it with one of several re-colouring products on the market. You may need to use a mild acid wash to clean the grout particularly if the stains are grease. Bleach won’t work on grease. Getting an even colour requires practice and skill and the final effect may depend upon the nature and extent of the staining.

You could always hand the problem over to Super Ceramic Services Ltd who will assess the staining and decide if re-grouting or staining are the best options. Once the problem is rectified you will have a beautiful floor that will enhance the value of your home for many years to come so it’s worth investing in it.

How do I fix Glass walls tiles? -

There has been a noticeable increase in the use of glass tiles, particularly in the consumer sector. With this in mind, the following should be borne in mind when using glass tiles:

Type of Tiles

There are several types of glass tiles available. Most glass tiles are produced with the colour on the back of the tile. In some instances the colour is glazed over and fired, thus producing a colour-bonded tile. Other glass tiles have a painted surface on the back of the tile, which is not fully bonded to the glass. Contact should be made with the tile supplier to determine which format of tile is being used. There are currently no British or International Standard for the production or fixing for glass tiles. It is therefore important to seek advice from the supplier and installer at the design stage regarding achievable finishes and appropriate areas of usage.

Setting Out

Some glass tiles may not be suitable for use in certain areas, for example, close to heat sources or wet areas. Advice should be sought from the supplier as to the suitability of the tiles in question. When using glass tiles it is important to aim for full modules to avoid light refraction and chaffing of tiles. Larger format glass tiles can vary in size slightly and this should be considered at the design stage.

Fixing

The choice of adhesive will depend of the type of glass tile. Contact should be made with the supplier to confirm the type of tile and recommended adhesive.

a) Fired colour bonded glass When fixing these products a single part flexible white Class C2 adhesive should be used. The tiles should be fixed using the solid bed method with no ribbing of adhesive and an even coat of adhesive spread over the back of the tile. This should ensure that no ribs of adhesive show through the tile.

b) Painted surface glass tiles. When fixing these products use either an epoxy Class R1 or Class R2 adhesive or a silicone based mirror adhesive when fixing this type of glass tile to walled surfaces. When using a mirror adhesive, the adhesive should be applied directly to the back of the tile, not the walled surface. The tile should then be fixed to the wall.

Health and Safety

Extreme care will be required when cutting any glass tiles. Protective goggles, safety gloves must be worn at all times and appropriate cutting tools will be necessary.

Are there any special considerations I should think of when fixing Porcelain or Vitrified tiles to an internal wall - There is an increasing trend towards fixing porcelain and vitrified tiles to walls. With differing manufacturing processes and materials, larger, thicker format tiles, complying with BS6431 are being produced. Porcelain and vitrified tiles, unlike porous bodied tiles, shrink in the firing process therefore certain allowances have to be made to dimensional accuracy in the manufacturing process. Bearing this in mind, the Tile Association has drawn up the following advice for clients planning to use vitrified tiles:

Porcelain /Fully Vitrified Tiles

Fully vitrified tiles which can either be unglazed or glazed characterised by the tile's low water absorption below 0.5% (BIa) Porcelain tiles are normally dry pressed using a body made from Kaolin clays, feldspar, silica and colouring oxides fired to around 1200 degrees.

Vitrified and Semi-Vitrified TilesTiles, which can either be unglazed or glazed. Tiles in this category can be either dry pressed or extruded and have water absorption of between 0.5 to 3%(vitrified) Class BIb – dry pressed, and 3% to 6% (semi-vitrified), Class BIIa – dry pressed.

Tolerances

Current British & European Standards for ceramic tiles define tolerances for dimensions of tiles. These vary depending on tile type and size as shown below:

Tolerances are also defined for centre curvature of tiles. These too vary depending on the type and size of tile.

(Negative curvature values indicate concave tiles)

The tolerances for tile fixing set down within British Standard BS5385 for tile fixing are demanding and as a result of the differences in manufacturing and fixing tolerances, special consideration has to be given to fixing vitrified tiles to walls.

Tile Fixing

Full guidance is given in British Standard, BS5385 Wall and floor tiling. The following points should be remembered:

Background

The ideal background is cement:sand rendering

Weight restrictions for tiling onto plaster and plasterboard are defined in BS5385:1, i.e. 32 kg/m2on plasterboard, and 20 kg/m2 on plaster The background to receive tiling should be fully cured, dry, clean, sound and nominally flat, such that when checked using a 2m straightedge, any gap under the straightedge should not exceed 3mm.

NOTE: Larger format tiles with a surface area greater than 0.1m2 may need additional mechanical fixing when used above 3 metres.

Setting Out

Vitrified and porcelain bodied tiles are often polished for aesthetic purposes. The polishing process, which involves grinding, will reduce the thickness of the tiles and possibly the overall dimensions of the tile. Therefore extra care should be taken at the design stage and during installation.

• Tiles should not be butt jointed

• Pressed tiles should be spaced at a minimum of 3mm

• Extruded tiles should be spaced at a minimum of 5mm

• Rectified or calibrated tiles should be spaced at a minimum of 2mm

Fixing

Lighting during tile fixing should be as close to the end use as possible

• Tolerances for surface flatness are defined in BS5385

• In a dry area a minimum area of contact of 75% should be achieved

• In wet areas solid bed fixing is required

Adhesives and Grouts

Use a polymer enhanced adhesive meeting the requirements for a cementitious Class

• C2 adhesive defined in BS EN 12004

• Grout meeting the requirements of BS EN 13888 should be applied as defined in BS5385

What should I consider when tiling in kitchen or food preparation areas? - Wall and floor tiling in food preparation, treatment and processing areas.

1. SCOPE

This specification defines the methods by which ceramic floor and wall tiles should be installed in premises where food is prepared, treated or processed. These may include kitchens, creameries, dairies, commercial food operations and all associated areas.

The Food Safety (General Food Hygiene) Regulations 1995, implementing the requirements of the EC Food Hygiene Directive require that floors, walls ceilings and surfaces (which come into contact with food) must be adequately maintained, easy to clean and, where necessary, disinfect. This will require the use of impervious, non-absorbent, washable and non-toxic materials. Floors should be slip resistant and walls should be smooth up to a height appropriate for the operations.The Regulations, however, allow the risks to food safety to be taken into account in the application of these requirements. In operations of low risk, materials with some absorption, for example, may be acceptable. This should be confirmed with the food hygiene authority at the design stage. In addition the Materials in Contact with Food Regulations – 1987 require that surfaces in contact with food should not transfer any constituent which could either endanger human health or taint the food. Ceramic tiles, installed and maintained in accordance with this specification, provide a durable, attractive, hard-wearing and slip-resistant surface which fulfils all of these requirements.

The TTA technical specification recommends methods for the installation of ceramic tiles using adhesives which conform to BS EN12004:2001 and grouts which conform to EN 13888:2002 in order to satisfy the due diligence requirements of food hygiene legislation. This specification may also be appropriate for any type of installation where hygiene is important, e.g. food storage areas, canteens and restaurants, hospitals and industrial clean areas.

2. DESIGN

Each location within a particular installation should be given separate consideration at the design stage. Tiles should be selected to suit service conditions. Vitrified ceramic floor tiles (Class BIa, BIb or AI) afford the best long term performance for commercial food preparation, treatment and processing areas. Slip-resistant tiles should be specified for wet service conditions, particularly where the floor will be subject to pedestrian traffic.

Scientific evidence (Holah and Thorpe, 1990) has shown that it is the surface finish on a microscopic scale which is important in determining a material’s cleanability and not surface finish on a visual scale. A slip resistant tile is therefore as likely to be as cleanable as a smooth tile of the same composition (Holah, 1994). Adequate falls should be incorporated in wet duty floor areas. Gradients between 1:80 and 1:40 are recommended. The direction of falls should be planned with the traffic flow in mind so that the traffic will move across rather than up and down the slope. The position of drainage channels and gulley's should be given special attention. Ceramic tiles cannot be relied upon to provide a tanking membrane and vulnerable areas e.g. installations on suspended floors, may need special consideration, for example tanking.

Food preparation areas which come into contact with aggressive matter are discussed in British Standard BS5385:4. Frequently wet areas are also referred to in BS5385:4. Wall and floor tiles should always be fully supported by a solid-bed of adhesive or mortar depending upon the fixing method used. Wall tiles should be light-coloured. All tile joints should be filled completely with an epoxy resin grout where they come into contact with food. It is recommended that white grout should be used for wall tiles and grey grout for floor tiles.

Certain wall tile areas, such as corners, pillars and those near to door openings, may be subjected to impact. These locations can be protected, for example, by securing metal angles, made of grade 316 stainless steel, over the tiling. Any gaps or crevices caused by securing these metal angles should be completely filled.

General design considerations are discussed in section 3 of BS 5385-1:1995, and BS 5385-3:1989. The installation of wall and floor tiling in accordance with this specification requires efficient supervision and the employment of skilled operatives. Recommendations on the basic workmanship required are given in BS 8000-11.1:1989.

2.1 MOVEMENT JOINTS

Movement joints should be provided in accordance with BS 5385-1:1995 Clause 3.5 for walls, and in accordance with BS 5385-3:1989 clauses 19 and 23.6 for floors. Their type and location should be decided at the design stage. Each movement joint should be at least 6mm wide and of a depth at least equal to the thickness of tile and bedding. Movement joints should be impervious and the sealant well bonded to the sides of the joints.

It is important that any movement joints already incorporated in the structure should not be tiled over but be carried through to the face of the tiling. In large areas of wall tiling movement joints should be provided at internal vertical corners and at 3- 4.5m centres horizontally and vertically. Movement joints should be provided around the perimeter of the floor and where floor tiles abut fixed machinery and structural fixtures such as columns, bases etc. Intermediate movement joints should be incorporated in large floor areas, as described in BS 5385-3: 1989, Clauses 19 and 23.6.

Stainless steel reinforced movement joints should be used for intermediate joints, especially where they are likely to be traversed by wheeled traffic. Movement joints should be filled completely with an appropriate sealant approved for use in food preparation areas.

3 MATERIALS

3.1 Cement

Cement should comply with the requirements of BS EN 197-1:2000 or BS 4027:1996. Cement complying with the requirements of BS 5224: 1995 may be used for rendering.

3.2 Sand

Sand for rendering should comply with type A of Table 1 of BS 1199:1976. Sands for cement:sand screeds and mortar beds should comply with BS EN13139, 0/4 category 1 and the recommendations of PD 6682-3.

3.3 Water

Water should be fresh and clean.

3.4 Tiles

Wall tiles to comply with BS 6431: Parts 2 : 6 or 9 (EN 121 or 176 or 159) or Classes BIa, BIb, BIII or AI complying with BS EN 14411. Floor tiles to be unglazed and to comply with BS 6431 : Parts 2 or 6 (EN 121 or 176) or Classes BIa, BIb, or AI complying with BS EN14411 and should be selected to suit service conditions.

3.5 Adhesives

Adhesives are normally selected on the basis of their bonding power, colour, flexibility and setting time. Cementitious adhesives should comply with the requirements of BS EN 12004:2001 for a C1/C2 adhesive. C2 adhesives are highly polymer-modified wall and floor tile adhesives for fixing tiles with a water absorption 0.5% or less.

They also may be specified where limited background vibration or movement can be expected or where the substrate is of high density with low suction. Where background movement or vibration is likely to occur deformable adhesives conforming to S1 or S2 of BS EN 12002 :2002 should be specified. Water-based polymer dispersions may be added to standard, polymer modified cement-based adhesives to improve their flexural properties, reduce their water permeability and enhance their bond strength, particularly to low porosity substrates and fully vitrified tiles.

3.6 Bonding Agent

A synthetic polymer is recommended for use as a water-resistant additive to cement:sand mortars and to provide a bonding slurry when mixed with cement prior to the application of screeds and renders.

3.7 Grouts

Floors and walls that do not come into contact with food do not require the use of epoxy grout. A cement based grout classified as CG1 or CG2 conforming to BS EN 13888 may be used. Epoxide grouts, classified as RG and conforming to the requirements of BS EN 13888:2002 provide smooth, impervious grout joints which are chemically resistant, easy to maintain in a sterile condition, and which do not taint food. Consideration should also be given to the use of a grout containing an antibacterial agent. They should meet the requirements of the Food Hygiene Regulations and have been approved for contact with food.

3.8 Sealant

Sealants for movement joints should be flexible and inert and should meet the requirements of the Food Hygiene Regulations.

4 INSTALLATION

4.1 Walls

4.1.1 Preparation

Walls should be of clay brickwork, concrete or lightweight block construction; see BS 5385-1:1995 clause 3.1. Ideally a cement:sand rendering should be applied as an intermediate substrate to provide the necessary measure of suction and accuracy. Walls should receive preparation in accordance with BS 5385-1:1995, clause 3.2 and should have been allowed to dry out for at least 6 weeks before any rendering is applied or before tiles are fixed direct.

4.1.2 Rendering

A 1:3 or 4 cement:sand mix should be used for the rendering, see BS 5385-1:1995 clause 3.3. To improve adhesion between rendering and background, a slurry mixture of water resistant bonding agent and Portland cement (1:2 by weight) can be applied over the background immediately before applying the rendering. The surface of the rendering should be left with a wood float finish. The rendering should be completed at least 14 days before tiling begins and, in addition, the prepared surface should be dry to receive the tiles.

4.1.3 Direct Fixing

If it is preferred to fix tiles direct to the structural wall, i.e. without prior rendering, this may necessitate the use of a thick-bed adhesive. The only preparation required is to ensure that the surface to be tiled is free from dust, oil or other form of contamination.

4.1.4 Adhesive

Fixing Whichever adhesive is used, solid-bed fixing is essential. This requires that the whole of the back of the tile should be in contact with the adhesive with no voids behind. Special solid-bed trowels are available to achieve this. After spreading the adhesive on the surface the open time will vary according to atmospheric conditions but is usually about 20 minutes.

Tiles should be fixed in position before surface drying of the adhesive occurs. Therefore, it is important not to spread more adhesive than can be covered with tiles within this period. It is sound practice to remove tiles occasionally as work proceeds to check that complete contact is being made with the adhesive. The tiles should be buttered with fresh material and refixed. Minimum joint widths of approximately 1-2mm should be left around every wall tile. Tiles can be adjusted up to 5 minutes after fixing to align the joints.

4.2 Floors

4.2.1 Preparation

Whatever the type of base on which tiles are to be laid, it is essential that the general principles of floor tile laying, described in British Standard Code of Practice BS 5385-3:1989 be observed. A suitable damp proof layer should be incorporated in the construction, and new concrete floors should be allowed to mature for at least 6 weeks before screeding or fixing commences.

4.2.2 Screeding

4.2.2.1 Cement:Sand Mortar Screed

A bonded 1:3 or 4 Portland cement:sand mortar screed should be laid in accordance with Appendix C of BS 5385-3:1989. The minimum thickness of the screed at any point should be 25mm. The design thickness should be 40mm. To improve adhesion between screed and concrete base, a 2 parts Portland cement and 1 part water resistant bonding agent/OPC cement slurry, by weight, can be applied over the base immediately before laying the screed. This screed should then be left for at least 3 weeks before tile fixing is commenced and in addition should be dry to receive the tiles.

4.2.2.2 Calcium Sulphate based Screed

Calcium Sulphate based screed are not suitable for damp, frequently wet or saturated areas such as commercial kitchens. Refer to the Tile Association document “Tiling to Calcium Sulphate based Screeds” for further information on this topic.

4.2.4 Tile Fixing

4.2.4.1 Adhesive Fixing

Ceramic floor tiles can be fixed directly to the base using C2 classified cementitious adhesives in accordance with BS 5385-3:1989, clause 24.4 and selected to suit substrate, tiles and service conditions. It is essential that solid-bed fixing is achieved i.e. no voids remain beneath the tiles. After spreading the adhesive on the surface the open time will vary according to atmospheric conditions but is normally approximately 20 minutes. Tiles should be fixed in position before surface drying of the adhesive occurs. Therefore, it is important not to spread more adhesive than can be covered with tiles within this period. It is sound practice to remove tiles occasionally as work proceeds to check that complete contact is being made with the adhesive. The tiles should be buttered with fresh material and re-fixed. Joints between ceramic tiles should be sufficiently wide to ensure that they can be filled with grout. Joints wider than 6 mm between floor tiles may not provide sufficient protection to the edges of the tiles.

4.2.4.2 Cement:Sand Mortar

Ceramic floor tiles appropriate for fixing cement:sand mortar can be fixed in accordance with BS5385- 3:1989 and BS5385-4:1992. The bedding mix should not be stronger than 1 part Portland cement and 3 parts sand, by volume, nor weaker than 1 part Portland cement and 4 parts sand, by volume. The thickness of the bed should be 15mm minimum and 20 mm maximum. A thin layer of a cement-based adhesive can be applied to the backs of tiles immediately before laying in cement:sand mortar, thereby increasing the bond strength about 3 or 4 times.

5 GROUTING

5.1 Walls and Floors

It is essential to allow time for the adhesive to set before grouting is carried out so as to avoid any disturbance of the tiles. The tiles should have been fixed for at least 24 hours before the joints are grouted; on low porosity backgrounds/bases at least 3 days should be allowed. If a rapid setting adhesive has been used, however, joints can be grouted after 2-5 hours.

Any surplus adhesive remaining on the face of the tiles or between the tile joints, after fixing, should be removed before it sets. During this time the tiling should be protected. Grouting of wall and floor tiles which come into contact with food should be carried out using a suitable epoxy grout as defined by the requirements of BS EN 13888:2002. The joints should be completely filled. Contact between food and tiling should be avoided for at least 7 days. if conditions but is usually about 20 minutes.

Tiles should be fixed in position before surface drying of the adhesive occurs. Therefore, it is important not to spread more adhesive than can be covered with tiles within this period. It is sound practice to remove tiles occasionally as work proceeds to check that complete contact is being made with the adhesive. The tiles should be buttered with fresh material and refixed. Minimum joint widths of approximately 1-2mm should be left around every wall tile. Tiles can be adjusted up to 5 minutes after fixing to align the joints.

6. CLEANING AND MAINTENANCE

Ceramic tiles are easy to clean and maintain in a hygienic condition in accordance with BS 5385- 3:1989. As with all types of floor and wall surfaces it is important to follow the correct cleaning regime to maintain hygiene. Wall and floor surfaces in food preparation areas should be maintained in good condition. Surfaces should be capable of refurbishment in locations where heavy traffic or wear could cause damage. Ceramic tiles are readily replaced locally to restore the tiling finish to its original specification. The appropriate cleaning and maintenance regime should form part of the tiling specification. Refer to the TTA document ‘The Cleaning of Ceramic Tiles’ for guidance on correct methodology.

7. REFERENCE DOCUMENTS

• BRITISH STANDARDS INSTITUTION:

• BS EN 197-1: 2000: Specification for Portland Cement.

• BS EN 13139:2002 Specification for aggregates from natural sources for concrete.

• BS 1199 and 1200: 1976: Specifications for building sands from natural sources + AMD 4510, AMD 4834, AMD 5126.

• BS 4027: 1996: Specification for sulphate-resisting Portland cement.

• BS 5224: 1995: Specification for masonry cement + AMD 2614.

• BS 5385: Wall and floor tiling

• Part 1: Code of Practice for the design and installation of internal ceramic wall tiling and mosaics in normal conditions.

• Part 3: Code of Practice for the design and installation of ceramic floor tiles and mosaics + AMD 7059.

• Part 4: Code of Practice for ceramic tiling and mosaics in specific conditions.

• BS 6431: Ceramic floor and wall tiles

• Part 2: 1984 (EN121): Specification for extruded ceramic tiles with a low water absorption (E<3%). Group A1.

• Part 6: 1984 (EN176): Specification for dust-pressed ceramic tiles with a low water absorption (E<3%). Group B1.

• Part 9: 1984 (EN159): Specification for dust-pressed ceramic tiles with a water absorption of E>10%. Group B111.

• BS 8000: Workmanship on Building Sites

• Part 11: 1989 Code of Practice for wall and floor tiling: Section 11.1 Ceramic tiles, terrazzo tiles and mosaics.

• BS EN 12004: 2001: Adhesives for tiles – Definitions and specifications

• BS EN 13888: 2002: Grouts for tiles – Definitions and specifications

• BS EN 14411: 2003: Ceramic tiles Annex

• A: Extruded ceramic tiles Group A1 Annex

• G: Dry-pressed ceramic tiles with low water absorption Group BIa Annex

• H: Dry-pressed ceramic tiles with low water absorption Group Bib Annex

• L: Dry-pressed ceramic tiles Group BIII

• BS EN ISO 10545:1997 Ceramic tiles

• THE FOOD SAFETY (GENERAL FOOD HYGIENE) REGULATIONS 1995

• Statutory Instrument 1995 No. 1763

• THE MATERIALS AND ARTICLES IN CONTACT WITH FOOD REGULATIONS 1987

• Statutory Instrument 1995 No.1523

• EUROPEAN COMMUNITIES COUNCIL DIRECTIVE 93/43/EEC

• On 14 June 1993 on the hygiene of foodstuffs. Official Journal of the European Communities No. L175/1, 19.7.93

• CAMPDEN & CHORLEYWOOD FOOD RESEARCH ASSOCIATION

• Holah. J. T. and Thorpe, R. H. (1990).

• Cleanability in relation to bacterial retention on unused and abraded domestic sink materials.

• Journal of Applied Bacteriology 69, 599-608

• Holah, J. T. (1994). Hygiene and safety in the food industry: compromise or complimentary? Seminar at RAPRA Technology Ltd, Shropshire, 29 September 1994

• Taylor, J. H. (1995). The Cleanability of Tiled Surfaces Compared with Generic Materials in New Condition.

• Taylor, J. H. and Holah, J. T. (In preparation). A comparative evaluation with respect to the bacterial cleanability of a range of wall and floor surface materials used in the food industry. Journal of Applied Bacteriology.

• THE TILE ASSOCIATION - Tiling to Calcium Sulfate based Screeds, published February 2002

Before I tile my Bathroom is there anything I should be think about? -

British Standard BS5385 is the Code of Practice for fixing wall and floor tiles. Part 4 of the Standard offers advice on fixing tiles in particular situations including wet areas such as in showers. When planning the tiling in your shower it is essential to tile onto an already water resistant background. Sand:cement render, dense concrete or water resistant tilebacker board are ideal backgrounds. Plaster, plasterboard, timber and timber-based products such as MDF or plywood are absorbent and should be made waterproof by the use of a waterproofing system (or tanking system).

Waterproofing systems can be painted on to the background. Most tile adhesive producers will have a range of waterproofing systems that coordinate with the tile adhesives and grouts in their product ranges. Check with Super Ceramic Services Ltd that the tile is suitable for use in a shower and/or bathroom.

The tile adhesive should be a water resistant polymer enhanced adhesive meeting the requirements of BS EN 12004 for a D2 dispersion adhesive or C1 or C2 for a cementitious adhesives and the tile grout should be water resistant, meeting the requirements of BS EN 13888. The tiles in showers should be fixed using the solid bed method, i.e. ensuring that there are no voids beneath the tiles. The joints between the tiles should be filled using a water resistant grout.

Special attention should be paid to sealing the gaps between the base of the tiling and where the tiling joins the base of shower units or bath and penetrations in the tiling (e.g. shower fittings), using a good quality anti-fungicidal silicon sealant. or a proprietary manufactured sealing strip specially designed for the purpose.

The shower should not be put into use until it has cured and is adequately dry.

Once fixed, how do I keep the tiles looking like new? - With proper care and attention, correctly installed,  good quality tiles should give many years trouble free service. Under normal circumstances they need little maintenance and are easily kept clean by wiping or mopping with warm water to which a neutral or nearly neutral detergent has been added. The cleaning solution should be allowed to stay on the surface for 5 to 10 minutes after which it should be removed by rinsing thoroughly with clean water.

The most important point to remember is the rinsing process, which removes the dirt. Inadequate rinsing can lead to a build up of deposits, which will gather dirt, making your tiles dull and floor tiles slippery.

Grit is the biggest enemy of any flooring material and a mat next to external doors is strongly recommended. Some terracotta, natural stone and slate tiles may need re-sealing. Ask Super Ceramic Services Ltd about this when buying your tiles.

Super Ceramic Services Ltd, 40 North Street East, Uppingham, Rutland, LE15 9QL.

Tel: 01572 821119   |   Fax: 01572 822008   |   sales@superceramicservices.com

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