Ceramic
CeramicTiling
Tiling INTRODUCTION / DESIGN
1.0 INTRODUCTION
A ceramic tiling finish is a system comprising no less than substrate, adhesive, stone, grout and movement
joints. All components are equally important and intimately related to one another. Adequate compatibility must
exist among the components as they could only function collectively. The system could only be as strong as the
weakest component, if not worse.
Therefore, design, preparation works, installation, protection and maintenance must take into consideration the
performance characteristics of each individual component as well as the in-situ environmental conditions that
prevail during the installation process. These considerations are similar for new technologies and materials in
Design for Manufacturing and Assembly (DfMA) such as Prefabricated Prefinished Volumetric Construction
(PPVC) and Prefabricated Bathroom Unit (PBU). It is recommended to refer to the respective guides for ceramic
tiling installation in these technologies.
Due to the volume constraint, this guide will focus on the interior installation of ceramic tiling.
2.0 DESIGN
To achieve good tiling works, it is critical to take into account the material selection besides proper installation
and quality control. It is important to understand the characteristics of the selected materials as well as their
compatibility with one another to achieve optimal performance.
The following design details should be considered:
• Tiles selection
• Adhesives
• Grout joints
• Movement joints
• Waterproofing
2.1. TILE SELECTION
Ceramic tile is a mixture of clay, quartz ferrous sand materials and water. The clays are mined from earth,
shaped and then coloured. The clays are then dried and subsequently fired at very high temperature in kilns.
Ceramic tile comes in two forms: glazed and unglazed. The primary portion of the tile, known as bisque,
can be naturally coloured with highly designed surfaces which can be glazed either in a high gloss or matte
finish. Glaze is a liquid glass that is baked onto the bisque. Most ceramic tiles have either a white or red body
colouration underneath the glazed finish.
Figure 2.1a illustrates the manufacturing process of ceramic tile extracted from “Design and Material Selection
for Quality – Vol 2”.
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Manufacturing process of ceramic tiles
Figure 2.1.a
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Ceramic Tiling DESIGN
Fine cracks could appear on the glazed surface when the bisque and glaze expand and contract at different
rates. When the cracks show on the surfaces of glazed tiles, it is called crazing. This is a phenomenon caused
by tensile stress between the glaze and bisque. In the kiln, if the tiles are fired up to high temperature too quickly
or cooled too quickly, it can also result in crazing as a result of thermal shock.
Table 1 (under 2.1.5 - Selection Criteria) of SS 483 shows the classification of ceramic tiles with respect to water
absorption and shaping. Dry pressing and extrusion are two common methods in the forming process for tile
manufacturing. Dry pressed and extruded tiles can be distinguished from the mechanical keys at the back of
the tile as shown in Figure 2.1.b and 2.1.c.
Mechanical key at the back of dry pressed tile Mechanical key at the back of extruded tile
Figure 2.1.b Figure 2.1.c
Once the ceramic tile is produced, it will be cut according to the required dimension. Proper equipment are
required to cut ceramic tiles.
2.1.1. TYPES OF TILE
The choice of tile depends on the location, functional use of the area and, increasingly in recent year,
environmental friendliness. Environmental friendly tiles are certified under the following schemes:
- Singapore Green Labelling Scheme (SGLS), administered by Singapore Environment Council (SEC).
- Singapore Green Building Product (SGBP) labelling scheme, administered by Singapore Green Building
Council (SGBC).
The various types of tiles include ceramic tile, porcelain tile, rectified tile, quarry (unglazed) tile, etc.
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2.1.2. Porcelain tiles, a type of Homogeneous tiles, are composed of fine porcelain clays and fired at a much
higher temperature. This makes the porcelain tiles hardier, less porous and thus more resistant to moisture
and stains as compared to ceramic tiles. Porcelain tiles have a consistent colouration and property throughout
the entire section of the tile. They are suitable for use in both indoor and outdoor conditions. Porcelain tiles are
harder to cut due to their density and hardness.
2.1.3. Rectified tile is defined as a tile that has had all edges mechanically finished to achieve a more precise
facial dimension. Unlike a typical factory-edged tile, rectified tile is cut to size after the firing process. This
process creates a precise, 90 degree angle smooth edge; as a result, the tiles can be laid with consistent grout
joints. Most tiles (both homogeneous and ceramic) may vary in size, after being fired, up to 1.0 % of its size. But
the size variations can be substantially minimised through the process of sawing or grinding after the tile is fired.
2.1.4. In recent years, large format ceramic tiles were introduced into the market. While ceramic tile is defined
as having a surface area not more than 3,600cm2 with tile edge less than 600mm, large format ceramic tile
can be defined as having a surface area of more than 3,600cm2 and tile edge of less than 1.2m. The thickness
of these tiles depend on the type and area of usage. They come in wide varieties of styles and lookalike
designs on the surface ranging from concrete, stones to high-polished porcelain. Large format ceramic tiles are
available in any style and color that regular tiles come in.
There is another type of large format ceramic tile known as the large ceramic panel (Figure 2.1.4). A ceramic
panel tile has a surface area of more than 1m2 with tile edge of more than 1.2m. Thin large format panel can be
supplied in 3m length by 1.5m width. They can also be fiberglass reinforced, mechanically cladded and bent.
The constraint of large format ceramic tile is that the wall and floor must be even and level. Therefore, the use
of appropriate adhesive and bedding is important. It is recommended to consult an adhesive supplier when
choosing adhesive for large format panels. The width of the grout joints must also be compatible with the tile
dimension.
Large format panel tile - Size can be as large as 3.6m length 1.5m width and only 6mm thick
Figure 2.1.4
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Ceramic Tiling DESIGN
2.1.5. SELECTION CRITERIA
Prior to starting any tiling works, it is important to ensure that the selected tiles are able to meet the project
specifications. Table 2.1.5 provides guidance on the selection criteria.
Table 2.1.5: Ceramic tile selection criteria
Ceramic tile Requirements
selection criteria
1. Water absorption - Water absorption in tiles provide a measure of porosity. A high water absorption value indicates
a porous tile body while a low value indicates a compact tile body.
- In wet area, tiles with low water absorption should be used.
2. Modulus of - Modulus of rupture and breaking strength of ceramic tiles give an indication on where the tiles
rupture and can be used. (Refer to SS 483).
breaking strength
- Light loading areas are those where normal low-density pedestrian traffic e.g. domestic and
office locations, are likely to occur.
- Heavy loading areas are those where high density pedestrian traffic, and/or heavy load, are
likely to occur, e.g. in industrial and engineering premises.
- Tiles that withstand the required loading need to be selected accordingly.
3. Abrasion - Resistance to deep abrasion of unglazed tiles for floor should refer to ISO 10545-6.
resistance
- Resistance to surface abrasion of glazed tiles for floor should refer to ISO 10545-7.
4. Slip resistance - For safety reason, the slip resistance classification needs to be established based on usage
of the location. Reference can be made to SS 485:2011.
5. Crazing resistance - If soaking of tiles are required, glazed tiles should be tested to confirm that soaking would not
lead to crazing should refer to ISO 10545-11.
6. Dimensions and - Tiles used should have adequate dimensional characteristics (length, width, thickness,
surface quality straightness or sides, rectangularity, surface flatness) and surface quality to match the design
expectation, e.g. joint width, uniformity and alignment.
7. Thickness - Generally, thin tiles are more vulnerable to impact damage.
- Such floor tiles should have a minimum thickness of 8mm for better functional usage.
- Ratio of tile thickness to size should be controlled. Thickness of tile should increase following
the increase in tile size to avoid cracks.
- Nowadays, bigger tiles with thin thickness are being fabricated with greater breaking strength
or impact resistance.
- Tiles can be tested for impact resistance in accordance to ISO 10545-5.
8. Special - Stain resistance should be considered for kitchen and supermarket and should refer to ISO
requirements 10545-14.
- Chemical resistance should be considered for laboratories, industrial kitchen and chemical
processing plant and should refer to ISO 10545-13.
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2.2. ADHESIVE BEDDING
Bedding refers to the mortar, or in general terms ‘thin-bed” adhesive, thick bed mortar or levelling bed which
is the screed or render (Figure 2.2). The lower and upper limits of the thickness of the adhesive should be
specified by the manufacturer. Site personnel should follow the manufacturer’s instructions and apply adhesive
only to the specified thickness.
Adhesive bedding
Figure 2.2
2.2.1. TYPES OF ADHESIVE
In accordance to EN 12004/12002 and ISO 13007-1, tile adhesives fall into 3 major categories:
• Cementitious (Type C): Mixture of hydraulic binding agents, aggregates and additives; to be mixed with
water or other liquid before use.
• Dispersion (Type D): Mixture of binding agent in the form of polymer dispersion, additives and other
mineral fillers which is ready for use.
• Reaction-resin (Type R): Mixture of synthetic resins, mineral fillers and additives in which hardening
occurs by chemical reaction.
2.2.2. ADHESIVES SELECTION
Some ceramic tiles are highly absorbent. It is important to select the correct adhesive to ensure its performance,
i.e. to limit water absorption from adhesive to the tiles.
There is no single formula of adhesive that is compatible with all types of tiles and substrates. It is important to
note that, depending on the formulator’s technical competence and marketing strategy, products belonging to
the same type of adhesive could perform significantly differently. Table 2.2.2.a and 2.2.2.b provides suggestions
on the selection of adhesives.
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Table 2.2.2.a: Adhesive selection criteria
Adhesive selection criteria Requirements
1. Types of tile - The adhesive materials should be compatible with the tiles used.
2. Types of substrate - Different substrate types and their characteristics affect significantly the
adhesive selection of the tile finish system.
- Table 2.2.4 provides a general guide on different types of substrate.
3. Application properties of adhesive - The requirement of open time (maximum interval after application at
which tiles can be embedded in the applied adhesive) should cater for
the site application needs, considering the differences between the site
conditions and that of a standard laboratory.
4. Final properties of adhesive - The requirement of tensile adhesion strengths should suit the worst
combination of site conditions and workmanship, considering the tensile
strengths after water immersion and after heat ageing as robustness and
durability checks.
Table 2.2.2.b: Types of substrate
Types of substrate Requirements
1. Floor
1.1 Reinforced concrete floor - Screeding required. The screed may be bonded or unbonded depending
on the flexibility and condition of the substrate.
- Pipes and ducts should not be laid within the thickness of a screed.
1.2 Screed thickness - Nominal thickness of site-batched bonded screed should be 40mm & not
< 25mm at any isolated point.
- Nominal thickness of site-batched unbonded screed should be 75mm
& not < 50mm at any isolated point. Otherwise, the screed should be
reinforced with non-oxidising mesh of 100mm centre and 2mm diameter.
- For proprietory screed, follow thickness recommended by manufacturer.
2. Wall
2.1 Masonry walls - Rendering required.
2.2 Reinforced concrete walls - If plump satisfies the conditions specified, they may be able to receive tile
installation directly. Otherwise, rendering would be required.
- A splash coat (typically comprises cement, dry sand and latex in the ratio
of 1:1:1 by weight) may be applied before rendering to enhance bonding.
2.3 Aerated precision concrete wall - If plump satisfies the conditions specified, only suitable primer may be
needed. Otherwise, rendering would be required.
- If in doubt, it is a good practice to seek the recommendations of the
manufacturers to ensure the compatibility of the render/plaster mix with
the APC blocks.
2.4 Proprietary partition walls - Manufacturers should certify the suitability of uses for these proprietary
partition walls.
- Installation to be in accordance with the manufacturers’ instructions.
2.5 Render thickness - For site-batched render, its total thickness should not be > 20mm,
otherwise, strips of non-oxidising ribbed metal lathing should be anchored
onto the substrate prior to plastering.
- For proprietary render, follow thickness recommended by manufacturer.
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2.3. SPECIFICATION OF GROUTS
The joint width of tiles is not just a matter of design preference. The manufacturing tolerance of the tiles should
also be considered. For example, when using more dimensionally accurate tiles (e.g. dry pressed tiles), the
joint width could be smaller than using dimensionally less accurate tiles (e.g. extruded tiles).
In accordance to BS 5385-3:2014, the width of the grout joint should not exceed the tile thickness. There is
a provision for wider joints if wider joints are required to accommodate dimensional irregularities in the tiles,
maintain modular control or provide a decorative effect. The depth of the grout joints should be at least 2/3 of
the tile thickness.
While the minimum joint widths may be different between the wall and floor tiles, it is a good practice to adopt
a uniform joint width for both tiles. This will enable the joints to be consistent and straight throughout the wall
and floor tiles.
Grout is the material that is used to fill up the gap between tiles and support the tiles. It is classified into
cementitious and reaction-resin types. They should have suitable fineness and consistency that are compatible
with the designed joint width, such that grout can fill the joints successfully. Selecting the right type of grout is as
important as selecting the right tile and adhesive. Before proceeding, it is advisable to test its compatibility with
the tile. Table 2.3 provides guidance on the selection criteria in accordance to BS EN 13888 and ISO 13007-3.
Table 2.3: Grout selection criteria
Grout selection criteria Requirements
1. Application properties - Cleaning time (time interval between filling the joints and start cleaning
the tiles).
- Service time (time interval after which the tiling can be put into service).
- Pot life.
2. Shrinkage resistance - Should be able to prevent cracking.
- Any cracking, either in the grout line itself or between the grout and tile,
should be considered as failure.
3. Abrasion resistance - Abrasion resistance is important for floor applications.
4. Compressive strength - Compressive strength is important for applications.
5. Water absorption - Water absorption is pertinent to stain cleaning considerations.
6. Chemical resistance - Chemical resistance can be a key property to certain applications such
as industrial kitchen and chemical processing plant.
2.3.1. CLASSIFICATIONS OF GROUT
There are 2 types and classifications of grout in accordance to EN 13888 and ISO 13007-3:-
• Cement-based grout (CG) : available in Sanded Grouts or Non-sanded Grout
Normal Performance (CG1)
Improved Performance (CG2)
• Epoxy-based grout (RG)
Grout is visible and can be water-resistant. However, in most Portland cement based grouts, water or other
liquids can still be absorbed into the joints due to its capillary pores. Table 2.3.1 describes different types of
grout and applications.
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Ceramic Tiling DESIGN
Table 2.3.1: Different types of grout and applications
Types of grout Description Application
Cement grout (CG) – Consists of fine graded aggregates, Portland - Used for larger grout joint - 3mm
Sanded cement, synthetic resins and coloured or larger.
pigments added with water retentive additive.
The water retentive additive allows the grout to - Excellent alternative for natural
stay moist until the cement cured. stone and heavier tiles
Cement grout (CG) – Consists of very fine filler, synthetic resins, - Used for smaller grout joint - 3mm
Non-sanded coloured pigment and water retentive additive. or smaller.
The water retentive additive allows the grout to
stay moist until the cement cured. - Easier to apply on dry or vertical
surfaces.
Epoxy grout (RG) Consists epoxy resin, silica fillers, pigments - Ideal for porous and moisture
and a hardener. Epoxy grout is waterless mix sensitive stones.
formed by mixing a base material (part A) and
a hardener (part B). - Have very low water absorption,
higher compressive strength, are
resistant to staining and easy to
maintain.
2.3.2. GROUT PERFORMANCE CRITERIA
Table 2.3.2.a: Guide on grout performance for CG based on EN 13888 and ISO 13007-3
Fundamental characteristics Requirement
1. Abrasion resistance ≤ 2000 mm3
2. Flexural strength ≥ 2.5 N/mm2
3. Compressive strength ≥ 15 N/mm2
4. Shrinkage ≤ 3 mm/m
5. Water absorption after 30 minutes ≤5g
6. Water absorption after 240 minutes ≤ 10 g
Additional characteristics Requirement
7. High abrasion resistance ≤ 1000 mm3
8. Water absorption after 30 minutes ≤2g
9. Water absorption after 240 minutes ≤5g
Table 2.3.2.b: Guide on grout performance for RG based on EN 13888 and ISO 13007-3
Grout performance Requirements
1. Abrasion resistance ≤ 250 mm3
2. Flexural strength ≥ 30 N/mm2
3. Compressive strength ≥ 45 N/mm2
4. Shrinkage ≤ 1.5 mm/m
5. Water absorption after 240 minutes ≤ 0.1 g
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2.3.3. JOINTS AT DOOR AREA
The joints of door frame to floor and wall should be neat, gap-free and consistent (Figure 2.3.1.a). When closed,
the gap between the door and floor should be neat and consistent. The joint at floor divider area (Figure 2.3.1.b)
should also be neat and uniform throughout.
Neatly cut tile at door frame Neat joints at floor divider of completed unit
Figure 2.3.1.a Figure 2.3.1.b
2.4. MOVEMENT JOINTS
Movement joints are provided to accommodate movement in large continuous finished areas, or between
adjacent building components (e.g. brick wall and concrete column) and dissimilar substrates. These can be:
• In-situ joints which are formed during construction or sawn cut afterwards, filled with filler board and
backer rod, and sealed with a suitable sealant or;
• Pre-fabricated movement joints which are installed prior to the laying of tiles.
The backer-rod material in the movement joint should be compatible with the sealant used. It should be flexible,
compressible without forcing sealant out.
The sealant should be capable of accommodating the anticipated amount of movement without loss of adhesion
to the sides of the joints and be able to withstand the normal service conditions affecting the installation, e.g.
resistance to water and, where applicable, ultraviolet light.
The designer, in consultation with the supplier/manufacturer, are encouraged to specify movement joints and
show locations and details on drawings and specifications. Table 2.4 provides guidance on the locations of
movement joints and their appropriate joint widths.
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Table 2.4: Location of movement joints and their appropriate joint widths
Location of joints Minimum joint width
1. Structural movement joints should be carried through screed/render, bedding and Not less than the existing
tile layer. If the joints in the base structure are not straight and parallel, or if their structural joint widths
layout does not coincide with that of the floor tiles, guidance should be sought from
the designer.
2. Where tilework abuts restraining surfaces, such as columns, beams, perimeter walls,
curbs, pipes and ceiling.
3. At junctions where the substrate changes alignments, such as concave wall corners, Interior walls - 3 ~ 5mm
or where the substrate changes materials, such as between conventional clay Interior floors – min. 5mm
bricks and aerated precision blocks.
4. At perimeters and to divide floor and wall tiling into bays at the following intervals:
• Interior walls at interval of 5 to 6m
• Interior floors at the interval of 5 to 7m
• Interior floors and walls exposed to direct sunlight at the interval of 3.6 to 7m
2.5. PLANNING OF TILE LAYOUTS
The designer should prepare tile layouts which take into consideration the minimum joint width and the tolerance
of selected tiles.
Tile layout planning should consider the size of tiles used and shape of the area to be tiled. Care should be
taken to minimise the number of tiles that need to be cut for satisfactory visual effect. Cut tiles should be placed
at less visible corners. They should be of width greater than half of the tile size.
V-Box is used to check tile squareness and size variation before laying, in order to minimise inconsistent joints
during installation. While handling the tiles, there should also be visual check for tile defects, damages, stain
marks and inconsistent tonality. V-Box can be customized according to the size of the tiles. Figure 2.5 shows
the use of V-Box to check tiles squareness and size variations.
V-Box to check tiles squareness and size variations
Figure 2.5
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Before commencing any pre-tiling work, it is important to check that all the services are well incorporated and
coordinated in the approved shop drawings.
To ensure that the owner’s requirements particularly on a project’s acceptable tolerances are fully understood,
the contractor should construct a mock-up unit for owner’s approval before carrying out the actual tiling works.
This arrangement enables the main contractor and sub-contractors involved to know the exact level of quality
which they are expected to deliver. A mock-up unit will also enable all parties to confirm the layout, detailing and
the compatibility of the different materials.
2.6. WET AREAS
Wet areas are areas within a building that are exposed to water splashing or direct wetting. The areas are
commonly installed with discharge outlets and provided with water inlet supply. It is important to seek the
recommendations of the suppliers when selecting tiles in wet areas.
Gradient in wet areas should be laid to fall in accordance to specification and towards the discharge outlet.
Gradient may vary depending on whether the area is enclosed or exposed to weather condition, and space
usage. The direction and gradient of the fall must also be planned and indicated in drawings. Insufficient
gradient, uneven laying of tiles and lippage in wet area may lead to ponding of water on the tiles.
2.7. WATERPROOFING
Waterproofing refers to the normal protection of the tiles from damages due to both rising damp and direct
contact with water, such as in a shower compartment.
Continuous rising damp due to capillary action should be prevented by a proper vapor barrier below floor slab
and/or of any damp-proof-course in wall.
A tile finish, even when its joints are filled with impervious grout, cannot stop water from passing through. In wet
areas, a waterproofing membrane should always be installed to prevent water penetrating to the neighboring
areas and below. The water trapped between the waterproof membrane and the tile layer can only evaporate
by passing through the tile layer.
The type of waterproofing material used for wet area has evolved over the years with cementitious waterproofing
being used most commonly in recent years. It is easy to mix and apply, and readily available from suppliers.
Please follow the manufacturers’ instructions to ensure an accurate mix of materials.
For more details on waterproofing in wet areas, refer to Good Industry Practices Guide – Waterproofing for
Internal Wet Area, CONQUAS® Enhancement Series.
Waterproofing membrane at wet areas
Figure 2.7
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