AVOIDING TILE FAILURESFrancesco Stronati
Director of Technical Services
Tuesday 19th October 2010
Malone House, Barnett Desmene Belfast
PREPARATION OF SUBSTRATES
SUITABLE FOR THE LAYING OF CERAMIC
TILES
ASSESMENT AND PREPARATION OF
SUBSTRATES:
• Cementitious screeds and screeds based on special binders
• Smoothing compounds
• Old ceramic or natural stone floorings
• Concrete
•Wood, Chipboard, PVC, linoleum or rubber floorings, metallic surfaces
• Render
• Gypsum or Anhydrite
• Lightweight cement blocks
• Old painted surfaces
TECHNICAL AND PERFORMANCE
CHARACTERISTICS OF THE SCREED
To be suitable for the laying of ceramic tiles or natural stone, a screed must have the following characteristics:
•Sufficient thickness
•Sufficient mechanical strength
•Solid
•Cured and dimensionally stable
•Dry
•Clean
•Free of cracks
•Smooth and level
UNBONDED SCREED
POLYTHENEPOLYTHENE
SCREEDSCREED
FLEXIBLE FLEXIBLE
MATERIALMATERIAL
UNBONDED SCREED
1. MINIMUM THICKNESS ≥≥≥≥ 5.0 cm
2. POLYTHENE
3. FLEXIBLE MATERIAL
4. FLOOR
5. BS 8204-1
FLOATING SCREED
1. MINIMUM THICKNESS ≥≥≥≥ 7.5 cm
(domestic / light loading ≥≥≥≥ 6.5 cm)
WITH ELECTROWELDED MESH
2. POLYTHENE
3. FLEXIBLE MATERIAL
4. INSULATING LAYER
5. FLOOR
BONDED SCREED
Casting of the screed over fresh slurry bond coat based of:
• Epoxy resin
• Synthetic-rubber latex additive mixed with water and with the material (binder) used to make the screed
HEATED SCREED
HEATED SCREED
1. SCREED THICKNESS (THICKNESS
OVER PIPES ≥≥≥≥3.5 cm)
2. ELECTROWELDED MESH
3. HEATING PIPES
4. FLEXIBLE MATERIAL
5. THERMAL INSULATION LAYER
6. FLOOR
WAITING TIME BEFORE CARRYING OUT HEATING CYCLE
Cement +
aggregate +
water +
MAPEFLUID N200
Cement +
aggregate +
water +
MAPEFLUID PZ 500
TOPCEM
PRONTO +
water
TOPCEM +
aggregate +
water
MAPECEM
PRONTO +
water
MAPECEM +
aggregate +
water
21 days 14 days 4 days 4 days 1 day 1 day
PRESENCE OF PIPES
Over the pipes there must always be a minimum
thickness of the screed of approx. 3.5 cm. To
reinforce this small section of the screed and to
limit the formation of cracks it is necessary to
position a wire mesh over the pipes.
It is essential that the heating system is
commissioned before any floor tiling is
commenced.
TECHNICAL AND PERFORMANCE
CHARACTERISTICS OF THE SCREED
To be suitable for the laying of ceramic tiles or natural stone, a screed must have the following characteristics:
•Sufficient thickness
•Sufficient mechanical strength
•Solid
•Cured and dimensionally stable
•Dry
•Clean
•Free of cracks
•Smooth and level
MECHANICAL STRENGTH
The mechanical strength of a screed must be
suitable for the foreseen service conditions and
for the type of floor covering to be laid:
• BS 5385, part 3, Annex C
SCREED COMPOSITION
• Water, cement and aggregates
• Water, cement, aggregates + superplasticizing admixtures (such as MAPEFLUID N200 or MAPEFLUID PZ 500)
• Normal setting, fast drying – 4 days - special binder (such as TOPCEM) to be mixed with water and aggregates
• Fast drying - 24 hours – special binder (such as MAPECEM) to be mixed with water and aggregates
• Fast (such as TOPCEM PRONTO) or quick (such as MAPECEM PRONTO) drying, ready-to-use, pre-blended mortar to be mixed only with water.
TOPCEM TOPCEM
PRONTO
MAPECEM MAPECEM
PRONTO
RESIDUAL MOISTURE (%)
after 24 hours
after 3 days
after 4 days
<4
<3
<2
<4
<3
<2
<2
<1,6
-
<2
<1,6
-
SMOOTHING COMPOUND 1÷÷÷÷ 4 days 1 ÷÷÷÷ 4 days 4 hours 4 hours
TIME BEFORE LAYING
ceramic
natural stone
wood
24 hours
2 days
4 days
24 hours
2 days
4 days
3 ÷÷÷÷4 hours
3 ÷÷÷÷4 hours
1 day
3 ÷÷÷÷4 hours
3 ÷÷÷÷4 hours
1 day
COMPR. / FLEX. Strength
(N/mm2)
after 24 hours
after 3 days
after 4 days
after 7 days
after 28 days
>7/4
-
>20/5
>25/6
>30/7
>7/4
-
>20/5
>25/6
>30/7
>30/5
>40/6,5
-
-
>45/7
>40/6
>50/7
-
-
>62/10
TECHNICAL AND PERFORMANCE
CHARACTERISTICS OF THE SCREED
To be suitable for the laying of ceramic tiles or natural stone, a screed must have the following characteristics:
•Sufficient thickness
•Sufficient mechanical strength
•Solid
•Cured and dimensionally stable
•Dry
•Clean
•Free of cracks
•Smooth and level
COMPACTNESS
The screed must be solid and well-blended throughout its entire thickness. If there are layers or areas with lower compactness it is possible to consolidate the screed by means of impregnation using:
• two-component epoxy-based primer (such as PRIMER EP(20%) or PRIMER MF(100%) in case plus PRIMER KL)
• one-component polyurethane-based primer (such as ECOPRIM PU 1K(100%))
• silicate mixture in water (such as PROSFAS(24%))
PRIMER EPPRIMER EP
PRIMER MFPRIMER MF
TECHNICAL AND PERFORMANCE
CHARACTERISTICS OF THE SCREED
To be suitable for the laying of ceramic tiles or natural stone, a screed must have the following characteristics:
•Sufficient thickness
•Sufficient mechanical strength
•Solid
•Cured and dimensionally stable
•Dry
•Clean
•Free of cracks
•Smooth and level
CONTROL JOINTS
The incorporation of check joints in the screed
make sure that the formation of cracks due to
hygrometric shrinkage occur in pre-established
sections of the screed.
Cuts are made in the screed to a depth of at least
1/3 of its thickness. The screed is, therefore,
locally weakened which favours the formation of
cracks exactly at those points.
Correct size for check
joints
Formation of shrinkage cracks
in the wrong position due to
shallow cuts in the presence of
an irregular substrate
WHEN ARE CONTROL JOINTS
REQUIRED?
In floating / unbonded screeds, they must be made every 20-
25 m² for internal applications, and at least every 16 m² for
external applications.
In the case of screeds made with controlled shrinkage
binders, such as TOPCEM or MAPECEM, TOPCEM PRONTO
or MAPECEM PRONTO the bay size may be increased
accordingly.
In bonded screeds, the joints must be made in
correspondence with the joints in the substrate.
The expansion joint in the tiles does not correspond with the control joint in the screed.
TECHNICAL AND PERFORMANCE
CHARACTERISTICS OF THE SCREED
To be suitable for the laying of ceramic tiles or natural stone, a screed must have the following characteristics:
•Sufficient thickness
•Sufficient mechanical strength
•Solid
•Cured and dimensionally stable
•Dry
•Clean
•Free of cracks
•Smooth and level
HIGH RESIDUAL MOISTURE
Too high amount of mixing
water
Aggregate too rich in fine
parts and dirty
No vapour barrier
Accidental contact with water
on the finished screed
Excessive wetting during
finishing and excessive
floating / trowelling
DRYING
EFFLORESCENCE OF
CALCIUM CARBONATE
CAUSED BY MOISTURE
COMING FROM
SUBSTRATE
It is necessary to ensure that, in case of absence
of a vapour barrier, also the layers below the
screed are dry.
In case of rising damp, a functioning and long
lasting vapour barrier must be guaranteed.
DRYING
TECHNICAL AND PERFORMANCE
CHARACTERISTICS OF THE SCREED
To be suitable for the laying of ceramic tiles or natural stone, a screed must have the following characteristics:
•Sufficient thickness
•Sufficient mechanical strength
•Solid
•Cured and dimensionally stable
•Dry
•Clean
•Free of cracks
•Smooth and level
CLEANING
The surface of the screed must be perfectly
clean.
Dust, laitance, dirt and debris must be removed
because they can compromise the adhesion of
the smoothing compound or of the adhesives.
6 c
m
1.5
cm
CLEANING
Remove dust and proceed with the application of a suitable
FIXING PRIMER based on synthetic resins dispersed in water, with also the aim to provide uniform substrate absorption
before levelling(such as PRIMER G or ECOPRIM T)
Where laitance is present, remove this layer mechanically and then proceed with the application of a suitable
CONSOLIDATING PRIMER CONSOLIDATING PRIMER based on epoxy resinsbased on epoxy resins, , to to consolidate the superficial part of the screedconsolidate the superficial part of the screed
(such as(such as PRIMER MF)PRIMER MF)
TECHNICAL AND PERFORMANCE
CHARACTERISTICS OF THE SCREED
To be suitable for the laying of ceramic tiles or natural stone, a screed must have the following characteristics:
•Sufficient thickness
•Sufficient mechanical strength
•Solid
•Cured and dimensionally stable
•Dry
•Clean
•Free of cracks
•Smooth and level
CRACKS
•Hygrometric shrinkage
• In correspondence with construction joints not well realized
• Above pipes where there was an inadequate thickness of the screed
Too high amount of mixing water
Too fine aggregate
Too high amount of binder
Lack of control joints
Before proceeding to apply a levelling
compound, it is necessary to monolithically
seal the cracks by pouring a solvent free two
component epoxy resin
(such as EPORIP, EPOJET or EPOJET LV)
Seal with EPORIP, EPOJET or EPOJET LV
epoxy resin, or with EPORIP TURBO polyester
resin
CRACKS
TECHNICAL AND PERFORMANCE
CHARACTERISTICS OF THE SCREED
To be suitable for the laying of ceramic tiles or natural stone, a screed must have the following characteristics:
•Sufficient thickness
•Sufficient mechanical strength
•Solid
•Cured and dimensionally stable
•Dry
•Clean
•Free of cracks
•Smooth and level
Requirement of REGULARITYRequirement of REGULARITYRequirement of REGULARITYRequirement of REGULARITY
FLATNESS (Floors and Walls)
Method: ISO 7976-1 clause 7.3.1
BS 5385-3 clause 7.1.4
Reference limit :
Tolerance = ± 3 mm under 2 m rule
Note: Laying with adhesive: flatness of ceramic floor
depends on flatness of substrate
ASSESMENT AND PREPARATION OF
SUBSTRATES:
• Cementitious screeds and screeds based on special binders
• Smoothing compounds
• Old ceramic or natural stone floorings
• Concrete
•Wood, Chipboard, PVC, linoleum or rubber floorings, metallic surfaces
• Render
• Gypsum or anhydrite
• Lightweight cement blocks
• Old painted surfaces
ECO PRIM T – MAPEPRIM SP
In case of laying over old ceramic or natural stone floorings it is very important to proceed with the
following operations:
1.Cleaning of old flooring
2.Abrasion of the surfaces when required
3.Examination of old flooring conditions(adhesion and presence of cracks)
4.Repair of damaged parts with NIVORAPIDNIVORAPID(+ LATEX PLUS)(+ LATEX PLUS) or with ADESILEXADESILEX P4P4
5.Laying of the new flooring respecting existing structural and expansion joints
ASSESMENT AND PREPARATION OF
SUBSTRATES:
• Cementitious screeds and screeds based on special binders
• Smoothing compounds
• Old ceramic or natural stone floorings
• Concrete
•Wood, Chipboard, PVC, linoleum or rubber floorings, metallic surfaces
• plaster
• Gypsum or anhydrite
• Blocks of cellular cement such as Gasbeton
• Old painted surfaces
ASSESMENT AND PREPARATION OF
SUBSTRATES:
• Cementitious screeds and screeds based on special binders
• Smoothing compounds
• Old ceramic or natural stone floorings
• Concrete
•Wood, Chipboard, PVC, linoleum or rubber floorings, metallic surfaces
• Render
• Gypsum or anhydrite
• Lightweight cement blocks
• Old painted surfaces
Timber floors must be firmly fixed using screws not nails or ring shank nails. The surface to be tiled
must be clean and free from wax, grease, oil, paint or other materials that can cause detachment.
Direct fixing to plywood, chipboard and floorboards is possible with the correct preparation, using the correct choice of adhesive and where necessary
anti-fracture membranes.
Levelling of substrates particularly deformable (timber floors, metallic surfaces, rubber, linoleum) can be
carried out by the use of smoothing compounds with high adhesion and elasticity, prepared by mixing ultra fast drying thixotropic cementitious materials (such
NIVORAPID or PLANIPATCH) with plasticizing admixtures (such LATEX PLUS).
The use of plasticizing admixtures reduces the modulus of elasticity of the smoothing compound and
therefore increasing the adhesion to “difficult”substrates.
MAPEI SMOOTHING AND LEVELLING
COMPOUNDS
ASSESMENT AND PREPARATION OF
SUBSTRATES:
• Cementitious screeds and screeds based on special binders
• Smoothing compounds
• Old ceramic or natural stone floorings
• Concrete
•Wood, Chipboard, PVC, linoleum or rubber floorings, metallic surfaces
• Render
• Gypsum or anhydrite
• Blocks of cellular cement such as Gasbeton
• Old painted surfaces
• To verify the performance of a render
or adhesion of coverings to the
substrate it must be determined by a
pull-out test with a dynamometer
• Fixing tiles to external façades must be carried out using improved
adhesives classified as C2 (according to EN 12004).
Consequently a render’s resistance to the pull-out test must be
≥≥≥≥ 1N/mm²
EXTERNAL DETACHMENT DUE TO COHESIVE FAILURE OF THE RENDER
Fixing ceramic or natural stone is possible
only after the curing of the render –
minimum 2 weeks (BS 5385 parts 1 & 2)
(7-10 days/cm of thickness)
It is advisable to insert a metallic mesh in
the render by string-courses and at the
border between concrete and masonry.
CRACKINGS BETWEEN CONCRETE AND MASONRY
crackbeam
masonryGalvanized
mesh
ASSESMENT AND PREPARATION OF
SUBSTRATES:
• Cementitious screeds and screeds based on special binders
• Smoothing compounds
• Old ceramic or natural stone floorings
• Concrete
•Wood, Chipboard, PVC, linoleum or rubber floorings, metallic surfaces
• Plaster
• Gypsum or anhydrite
• Blocks of cellular cement such as Gasbeton
• Old painted surfaces
Plasters based on gypsum must be at least 4 weeks
old. Anhydrite screeds must have residual moisture
less than 0.5% (by weight)
When the laying of tiles has to be carried out using
cementitious adhesives, the gypsum based
substrates must be treated in advance with a primer
(such as PRIMER GPRIMER G) to prevent the chemical
reaction between gypsum sulphates and cement
aluminates which, in damp environments, forms a
salt that can cause the detachment of the covering.
In addition anhydrite screeds must be abraded to
remove any surface laitance.
ASSESMENT AND PREPARATION OF
SUBSTRATES:
• Cementitious screeds and screeds based on special binders
• Smoothing compounds
• Old ceramic or natural stone floorings
• Concrete
•Wood, Chipboard, PVC, linoleum or rubber floorings, metallic surfaces
• Plaster
• Gypsum or anhydrite
• Lightweight cement blocks
• Old painted surfaces
EXTERNAL FIXING: fixing directly on this substrate is
not advisable since it tends to be dusty, mechanically
weak and, therefore, unable to contrast the stresses,
caused by different thermal expansion coefficient,
between substrate and covering materials.
In these cases it is ALWAYS necessary ,before laying
coverings materials, to apply a cementitious render
reinforced with galvanized mesh.
INTERNAL FIXING: it is possible to fix the material
directly on cellular or expanded concrete by applying
beforehand a coat of PRIMER G diluted 1:1 with water.
ASSESMENT AND PREPARATION OF
SUBSTRATES:• Cementitious screeds and screeds based on special
binders
• Smoothing compounds
• Old ceramic or natural stone floorings
• Concrete
•Wood, Chipboard, PVC, linoleum or rubber floorings, metallic surfaces
• Plaster
• Gypsum or anhydrite
• Blocks of cellular cement such as Gasbeton
• Old painted surfaces
ALWAYS REMOVE old paintwork before
fixing tiles.
If it is not removed, the bond of the
covering is not guaranteed over a long
period of time, because the paint may
soften and flake off which would lead to
detachment of the tiles.
THE EUROPEAN STANDARDS
• EN 12004ADHESIVES FOR CERAMIC TILES: DEFINITIONS AND
SPECIFICATIONS
• EN 13888GROUTS FOR CERAMIC TILES: DEFINITIONS AND
SPECIFICATIONS
• EN 12002ADHESIVES FOR CERAMIC TILES :
DETERMINATION OF THE TRANSVERSAL
DEFORMATION OF CEMENTITIOUS ADHESIVES
Standards that define the tests methods to determine
the characteristics of adhesives and grouts
Thank You.
STONE
MATERIAL
STONE
MATERIAL
CLASSIFICATION
According to Italian Standard UNI 8458“Terminology and classification of stone materials”ornamental rocks can be classified in four different
categories :
MARBLEMARBLE
GRANITGRANIT
TRAVERTINETRAVERTINE
STONESTONE
AGGLOMERATES
MARBLE, GRANIT OR QUARTZ CRUSHED
+
POLYESTER RESIN, EPOXY RESIN OR CEMENT
PROBLEMS OF STONE MATERIAL
• DIMENSIONAL STABILITY TO WATER AND TO
HEAT
• SENSITIVITY TO HUMIDITY THAT CAUSES
STAINS OR EFFLORESCENCES
COEFFICIENT
OF THERMAL
EXPANSION
(°C-1)
∆T
(°C)
EXPANSION
(mm/m)
AGGLOMERATE
MATERIAL35 • 10-6 70 2,45
NATURAL STONE 7 • 10-6 70 0,49
Dimensional stability laboratory
Simulation test with humid felt
Detail of the sensors positioned on slab
In the first 6 hours of measuring it is possible to
register reduced or very strong movements, so
that the materials can be classified in three
categories:
CLASS ACLASS AMovements inferior
to 0,3 mm after 6
hours
CLASS BCLASS BMovements between
0,3 mm and 0,6 mm
after 6 hours
CLASS CCLASS CMovements higher
than 0,6 mm after 6
hours
0 3 6 9 12 15 18 21 24
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
Movimento (mm)
Tempo di prova (h)0 3 6 9 12 15 18
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
Tempo di prova (h)21 24 0 3 6 9 12 15 18
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
Tempo di prova (h)21 24
Bonding test
(for slabs belonging to Class B or C)
Warping of a slab in Verde Alpi because of the application
carried out with normal-set cementitious adhesive
CASE HISTORY
Tests No. class A class B class C
455
Natural
stones
367
(80,7%)
37
(8,1%)
51
(11,2%)
249
Cement
agglom.
87
(34,9%)
95
(38,2%)
67
(26,9%)
285
Resin
agglom.
180
(63,2%)
59
(20,7%)
46
(16,1%)
989 in
TOTAL
634
(64,1%)
191
(19,3%)
164
(16,6%)
class C
17%
class B
19% class A
64%
Class B +
class C =
36% !
STAINS OF STONE MATERIALS:
CAUSES
• Presence of rising damp from substrate in
absence of a vapour barrier
• Installation carried out on a screed with very high
residual humidity
• Installation carried out by the use of a traditional
mortar bed or with a non fast-setting cementitious
adhesive
• Thickness of thin material
• Deposits of “iron” substances present on the back
of the marble after the working process.
• High concentration in the stone of iron sulphide
(FeS2), that is pyrite, which, in contact with water
and oxygen, transforms, after different chemical
processes, into iron hydroxide; this last one, in
form of solution, seeps into the stone porosities
and is visible on the surface as yellowish stains
that can in the time affect the whole surface and
become always darker.
STAINING OF WHITE CARRARA MARBLE
• In this specific case, the presence of “pyrites” in the structure of the marble may lead to a complete colour change.
Installation of floorings and coverings with improved
cementitous adhesives (C2) or improved reactive
adhesives (R2), of optional class F-T-E, according to the
norm EN 12004 depending on the type of installation to
be carried out, of the material to be laid and on its
belonging class
Grout the joints with:
Cementitious mortar classified as
CG2 according to EN 13888
(possibly mixed with polymeric admixture)
or with epoxy mortar
classified as RG
according to EN 13888
Thank You.