Conten ts :
Introduction 1
Substrates 3
Laying and
grouting the
slabs
4
Choosing the
adhesive 5-6
Laying recom-
mendations 7
Grouting 8
FOCUS ON JANUARY 2012
LAYING THIN PORCELAIN
STONEWARE SLABS
More and more often, industries are
striving to apply the concept of sus-
tainability to their products, to the
extent that the entire production
cycle seems to be undergoing
reformation, starting from the de-
sign phase to industrialisation of
new materials. Some examples of
this endeavour are the develop-
ment of new design solutions, the
reduction of the environmental im-
pact through the use of recycled
materials and the innovation of pro-
duction processes. The ceramics
sector is highly involved in this in-
novative process and it is no coinci-
dence that many companies oper-
ating in this area have developed
thin ceramic materials, in order to
reduce the amount of raw materials
used, with positive results in terms
of reduced transport costs due to
lighter slabs, as well as energy sav-
ings per square metre. The use of
thin slabs presents other ad-
vantages, such as less difficulty in
handling the slabs, reduced loss of
treadable areas in renovation works
with ensuing savings on demolition
works, less difficulty in cutting the
slabs and lighter loads bearing on
the structures.
The thin porcelain stoneware slabs
currently available in the market fall
into two categories:
1 - Slabs obtained through a gradu-
al compaction process on a con-
veyor belt without the aid of
moulds, with subsequent baking at
1200°C and trimming.
1
2 With a thickness of 3 mm and a maximum
size of 1 x 3 m, these
slabs are available in three formats:
1.a - Natural 3 mm thick slabs, mainly suita-
ble for wall applications.
1.b - 3.5 mm thick slabs reinforced by
means of a glass mat fixed to the back with
polyurethane resin during the production
process and characterised by a greater tread
resistance.
1.c - Paired slabs having a total thickness of
7 mm, consisting of two 3 mm slabs joined
with an interposed fibreglass mat, suitable
for high traffic flooring.
2 - Slabs pressed in ceramic moulds and
then baked at 1200°C, with a thickness rang-
ing between 4 and 5 mm and a maximum
format of 8100 cm². The reinforced back is
not available for this type of material.
Reduced thickness, large formats, extremely
low water absorption that characterises
porcelain stoneware and a bonding surface
consisting of a glass mat embedded in poly-
urethane resin are the distinctive features
that these ceramic products have in com-
mon, all of which must be considered for the
installation to favour adequate surface dura-
bility.
The purpose of this document is to provide
the correct guidelines to plan the installation,
starting with the examination of the sub-
strates and ending with the choice of the
most suitable adhesives and grouting materi-
als depending on the intended use. In order
to simplify the use of this operation manual,
summary tables of practically every possible
kind of installation have been included when
possible. Therefore, the people operating in
this field can easily access the parts that in-
terest them and obtain the information they
require in a short time.
FOCUS ON LAYING THIN PORCELAIN STONEWARE SLABS
Natural 3 mm thick slabs
3.5 mm thick slabs reinforced
Flatness
Due to the thinness of the slabs, flatness is an
essential requirement of the substrates. In this
case, tolerance is inferior to that of substrates
used when laying slabs with a regular thick-
ness. While the tolerance measured with a 2 m
long straight edge for the latter is equal to ± 3
mm, it should not exceed ± 2 mm in the case of
thin slabs. A more restricted tolerance is neces-
sary to prevent the voids underneath the slabs
from causing them to break in the event of con-
centrated loads or accidental falls of heavy ob-
jects. If the flatness does not fall within this tol-
erance limit, levelling or self-levelling cement
mortars must be used, such as:
Aging
Whatever the nature of the substrates, they
must have completed their aging cycle for them
to be stable and not subject to shrinkage once
the slabs are laid. In the case of traditional ce-
ment-based screeds, aging can vary according
to the season, ranging from 7 to 10 days per
centimetre of thickness. Shorter waiting times
are attainable by using special normal-setting
fast-drying hydraulic binders, such as LITO-
CEM, which allows ceramics to be laid after 24
hours, instead of common Portland cement.
Aging lasts at least 3 months in the case of
concrete surfaces. Gypsum-based substrates,
such as anhydrite-based screeds or gypsum
plasters, must reach a maximum residual hu-
midity of 0.5%. For cement-based pre-mixed
plasters, it is recommended to follow the suppli-
er's recommendations concerning aging and
the mechanical strength.
Cleaning
Substrates must always be clean, free of loose
fragments, paint, wax, grease, oil or anything
else that can affect the correct adhesion of the
product. Concrete substrates must be cleared
of release agent residues. Existing ceramic
surfaces must be thoroughly degreased with
alkaline detergents or with a caustic soda water
solution.
Mechanical strength
In flooring, the substrates must have adequate
mechanical compressive strength in relation to
the intended destination area. For instance, the
compressive strength of a cement screed used
for a residential indoor area must be at least 20
N/mm2, whereas the adhesion to the substrate
of a cement-based or gypsum-based plaster
applied to an internal wall must be at least 0.5
N/mm2.
SUBSTRATES
FOCUS ON
3
LITOLIV EXTRA 15
(fast-drying and hardening self
-levelling, free from shrinkage
cement for a thickness range
of 1 to 15 mm, with very low
emission of volatile organic
substances, EMICODE EC1
certified, for indoor use).
LITOLIV S40 ECO
(Fibre-reinforced, fast-drying
and hardening self-levelling
cement for 3 to 40 mm thick
substrates).
LITOPLAN RAPID
(Thixotropic cement-based
levelling layer with ultra rapid
drying and hardening for verti-
cal and horizontal applications
from 1 to 25 mm thicknesses.)
LAYING THIN PORCELAIN STONEWARE SLABS
FOCUS ON
Laying and grouting the slabs 4
Certain guidelines are valid for all slab formats
and every kind of application (flooring, wall, in-
door, outdoor, residential, commercial, industri-
al, etc.). These recommendations are:
1. The double coating technique must always
be adopted when using the adhesive, applied
on the substrate as well as the back of the slabs
with the proper notched trowel, to achieve thor-
ough wetting and prevent the formation of voids.
2. A 2-3 mm space must be left between the
slabs to interrupt surface continuity, in order to
reduce the elasticity modulus and, therefore, its
rigidity. The elastic modulus of the grouting ma-
terial is significantly inferior to that of the slabs.
Conveying greater elasticity to the tiled surface
prevents dangerous stresses due to expansions
caused by temperature changes, hygrometric
shrinkage or settling of the structures that could
lead to the detachment of the slabs.
3. In the case of surfaces larger than 25 m2, it is
mandatory to create elastic fraction joints and
respect possible structural joints. Likewise, pe-
rimeter joints are required in correspondence
with walls or other elevations, such as columns,
steps, etc., on smaller surfaces also.
Choosing the adhesive
The choice of the adhesive is determined by
several factors listed below and will be reported
in the following synoptic tables for additional
clarity. The factors that determine the choice of
the adhesive are:
· Format of the slabs
· Type of slabs: "natural" slabs without rein-
forcement or "reinforced" with a glass mat on
the back
· Type of substrate
· Indoor or outdoor areas
· Flooring or wall
· The need to apply the ceramic coating quickly
LITOELASTIC
Two-component epoxy-
polyurethane reactive ad-
hesive for laying ceramic
tiles and natural stone.
CEMENTKOL K21
Cement-based adhesive for laying ceramic tiles.
LATEXKOL
Elasticising synthetic latex
for cement-based adhe-
sives.
LITOSTONE K99
Fast-drying and harden-
ing, high performance
cement-based white ad-
hesive for ceramic tiles
and natural stone to be
laid. Ideal for overlaying.
SUPERFLEX K77
High-performance, deformable, no
vertical slip cement-based adhe-
sive with extended setting time,
particularly suitable for laying
large formats. Ideal for overlaying
and heated flooring.
LAYING THIN PORCELAIN STONEWARE SLABS
FOCUS ON
5
Substrates
Normal-setting adhesives Quick-setting adhesives
TAB. 1 NATURAL THIN
SLABS FOR
INDOOR FLOORING
Format of the slabs Format of the slabs
≤ 3600 cm² ˃ 3600 cm² ≤ 3600 cm² ˃ 3600 cm²
Adhesives (type and class) Adhesives (type and class)
Cement-based screeds
SUPERFLEX K77
(C2TE -S1)
CEMENTKOL K21
+ 30% LATEXKOL
(C2-S2)
LITOSTONE K99
+ 30% LATEXKOL
Diluted in water 1:1
(C2FE-S1)
LITOSTONE K99
+ 30% LATEXKOL
(C2FE-S2)
Anhydrite screeds*
Heated flooring
Concrete
Existing ceramic, natural stone and marble floorings
Wood, PVC, rubber, metal surfaces
LITOELASTIC (R2T)
*After Primer C has been applied ATTENTION: many ceramic companies do not lay non-reinforced thin tiles on the floor, regardless of them being laid on screed or overlaid. Follow the instructions provided by the manufacturer and contact our technical department beforehand.
Substrates
Normal-setting adhesives Quick-setting adhesives
TAB. 2 NATURAL THIN
SLABS FOR
INDOOR COATINGS
Format of the slabs Format of the slabs
≤ 3600 cm² ˃ 3600 cm² ≤ 3600 cm² ˃ 3600 cm²
Adhesives (type and class) Adhesives (type and class)
Cement-based plasters
SUPERFLEX K77
(C2TE -S1)
CEMENTKOL K21
+ 30% LATEXKOL
(C2-S2)
LITOSTONE K99
+ 30% LATEXKOL
Diluted in water 1:1
(C2FE-S1)
LITOSTONE K99
+ 30% LATEXKOL
(C2FE-S2)
Gypsum-based plasters*
Plasterboard or gypsum-
based panels*
Concrete
Existing ceramic, natural stone and marble coatings
Wood panelling and metal surfaces
LITOELASTIC (R2T)
*After Primer C has been applied
TAB. 3 NATURAL THIN
SLABS FOR
OUTDOOR COATINGS
Substrates
Normal-setting adhesives Quick-setting adhesives
Format of the slabs Format of the slabs
≤ 3600 cm² ˃ 3600 cm² ≤ 3600 cm² ˃ 3600 cm²
Adhesives (type and class) Adhesives (type and class)
Cement-based plasters
SUPERFLEX K77
(C2TE -S1)
CEMENTKOL K21
+ 30% LATEXKOL
(C2-S2)
LITOSTONE K99
+ 30% LATEXKOL
Diluted in water 1:1
(C2FE-S1)
LITOSTONE K99
+ 30% LATEXKOL
(C2FE-S2) Concrete
Choosing the adhesive
LAYING THIN PORCELAIN STONEWARE SLABS
FOCUS ON
6
TAB. 4 REINFORCED THIN SLABS
FOR INDOOR
FLOORING
Substrates
Normal-setting adhesives Quick-setting adhesives
Format of the slabs Format of the slabs
≤ 5000 cm² ˃ 5000 cm² ≤ 5000 cm² ˃ 5000 cm²
Adhesives (type and class) Adhesives (type and class)
Cement-based screeds
SUPERFLEX K77
(C2TE -S1) CEMENTKOL K21
+ 30% LATEXKOL
(C2-S2)
LITOSTONE K99
+ 30% LATEXKOL
(C2FE-S2)
LITOSTONE K99
+ 30% LATEXKOL
Diluted in water 1:1
(C2FE-S1)
Anhydrite screeds*
Concrete
Existing ceramic, natural stone and marble floorings
Heated flooring
CEMENTKOL K21
+ 30% LATEXKOL
(C2-S2)
LITOSTONE K99
+ 30% LATEXKOL
(C2FE-S2)
Wood, PVC, rubber, metal surfaces
LITOELASTIC (R2T)
*After Primer C has been applied ATTENTION: many ceramic companies do not lay non-reinforced thin tiles on the floor, regardless of them being laid on screed or overlaid. Follow the instructions provided by the manufacturer and contact our technical department beforehand.
Substrates
Normal-setting adhesives Quick-setting adhesives
TAB. 5 REINFORCED THIN SLABS
FOR INDOOR
COATINGS
Format of the slabs Format of the slabs
≤ 5000 cm² ˃ 5000 cm² ≤ 5000 cm² ˃ 5000 cm²
Adhesives (type and class) Adhesives (type and class)
Cement-based plasters
SUPERFLEX K77
(C2TE -S1)
CEMENTKOL K21
+ 30% LATEXKOL
(C2-S2)
LITOSTONE K99
+ 30% LATEXKOL
Diluted in water 1:1
(C2FE-S1)
LITOSTONE K99
+ 30% LATEXKOL
(C2FE-S2)
Gypsum-based plasters*
Plasterboard or gypsum-
based panels*
Concrete
Existing ceramic, natural stone and marble coatings
Wood panelling and metal surfaces
LITOELASTIC (R2T)
*After Primer C has been applied
TAB. 6 REINFORCED THIN SLABS
FOR OUTDOOR COATINGS
Substrates
Normal-setting adhesives Quick-setting adhesives
Format of the slabs Format of the slabs
≤ 5000 cm² ˃ 5000 cm² ≤ 5000 cm² ˃ 5000 cm²
Adhesives (type and class) Adhesives (type and class)
Cement-based plasters CEMENTKOL K21
+ 30% LATEXKOL
(C2-S2)
LITOSTONE K99
+ 30% LATEXKOL
(C2FE-S2) Concrete
Choosing the adhesive
LAYING THIN PORCELAIN STONEWARE SLABS
FOCUS ON
7
In addition to the environmental and technical
characteristics listed at the beginning of this docu-
ment, thin slabs meet the requirements of archi-
tects and designers who choose this kind of mate-
rial, in order to obtain continuous surfaces, the-
reby minimising the grout joints, thanks to the pos-
sibility of being produced in large formats. Never-
theless, a number of precautions must be taken
by the installers when laying large formats and
these are provided below.
Firstly, utmost attention must be paid when mo-
ving these slabs, which can reach a size of 1 x 3
meters. In such cases, it is essential to follow the
recommendations of the manufacturers, who pro-
vide special frames designed to help move the
slabs safely in order to prevent breaking them.
Likewise, it is necessary to involve a number of
people in order to prevent the slabs from being
bent too much and risk breaking the corners.
As mentioned, thin slabs always require the dou-
ble coating technique during installation, therefore
it is preferable to choose adhesives with an exten-
ded setting time (E) to prevent the film on the sur-
face from forming too quickly or, in any case,
before laying the slabs. This precaution is more
important in the presence of warm weather, for
slab formats exceeding 3600 cm² or when instal-
led on an outdoor facade, where it is likely to be
exposed to more ventilation.
Maintaining flatness is one of the main difficulties
encountered when laying large format thin slabs.
Often, "steps" are formed at the corners because
the substrates are not perfectly flat or due to the
flexibility of the slabs themselves. The installers
can use state-of-the-art levelling spacers, which
guarantee ideal positioning of the slabs until the
adhesive is completely hardened.
Laying recommendations
LAYING THIN PORCELAIN STONEWARE SLABS
FOCUS ON
8
LITOKOL S.p.A. Via G. Falcone 13/1
42048 Rubiera (RE) Italy Tel: +39 0522 622811 Fax: +39 0522 620150
[email protected] www.litokol.it
A valuable help for your work: view and
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FOCUS ON at www.litokol.it
The joints can be grouted using cement-based
grouting mortars as well as two-component
epoxy mortars. If a cement-based product is
used, it is generally preferable to opt for fine-
grain products as these slabs are normally laid
with 1 to 3 mm joints. For such cases, Litokol
suggests LITOCHROM 1-6, a CG2 class ce-
ment-based grouting mortar (improved cement-
based grouting mortar) compliant with UNI EN
13888, available in a variety of 16 colours
In order to obtain more resistant grouts, which
are completely waterproof and easy to clean,
Litokol recommends using LITOCHROM
STARLIKE® epoxy mortar, classified as RG
(reactive grouting mortar), compliant with UNI
EN 13888 and ideal for 1 to 15 mm joints. This
product comes in a particularly wide variety of
colours, featuring 103 finishes, and hence it is
able to satisfy every aesthetic requirement.
Thanks to the collaboration with OTTO-
CHEMIE, a leading manufacturing company of
sealants in cartridges, Litokol is able to offer its
clients acetic silicones that match the STARLI-
KE®colours, so it is possible to create flexible
expansion joints and seal the fittings with the
GROUTING
LAYING THIN PORCELAIN STONEWARE SLABS