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

info@litokol.it 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