Beginners guide - Problems/Solutions

Tilers Forums Official Sponsors

Nice work monty, I don't have the webbers manual and I suspect there are still alot who don't as well. Very infomative and with pics as well :grin:. Great job M8 your a STAR!!:thumbsup:
 
Tiling uneven surfaces

Problem

It is important, both for appearance
and for safety, that the finished tile
surface is flat with no tiles standing
higher than the others. Providing the
normal tiling practices are followed
this is straightforward on flat, level
substrates. If the substrate is not flat
then a number of problems can arise.



13076_img.jpg




A serrated adhesive spreading trowel, when used at a constant angle, enables the even distribution of adhesive onto the substrate. If the tiles are all bedded with a similar force they should be at the same height with only minimal unevenness. However, if the substrate is not level, this is much more difficult to achieve and there is more chance that some edges will be standing proud.






13078_img.jpg








Localised deep holes may result in a bed thickness that exceeds the specification for a thin-bed adhesive.

Patching such holes can be time consuming if there are more than a few of them.







13080_img.jpg








In some instances, for example when tiling over a layer of existing ceramic tiles, the above mentioned problems may be combined.

Some tiles may need to be removed because they are unsound, whilst others may have been imperfectly fixed and exhibit some variation in height.







13082_img.jpg








Uncalibrated natural stones are stones that have been split along natural fracture planes rather than machine cut. The result is a stone that varies in thickness, both from within each stone and from piece to piece. These types of stones require an adhesive that can be applied to greater thickness than normal.



Solution

Use correct material depending on condition of substrate


There are a number of possible solutions depending on the condition of the substrate. A levelling compound will give a smooth surface but this does not help with uncalibrated stone where a high-build adhesive must be used. Deep holes should be filled first with a repair mortar.



Solution 1:
Use a levelling compound

A levelling compound can be used to smooth out
irregularities, holes and gaps between existing tiles etc.
and provide a flat and level surface for tiling.
Ensure that the surface is clean, dry and sound. Any
existing tiles, paint etc. must be firmly adhered.
Prime porous surfaces with appropriate
and
impervious surfaces with appropriate primer
.Allow primer to dry,
Pour the appropriate levelling compound to the
required thickness
. Make sure that any
movement joints in the substrate are carried through
the screed and tiling layer.
Fix the tiles using a
cement-based adhesive as
appropriate for the type of tile. Allow the adhesive to
set fully and then grout the joints.




Solution 2:
Use a thick bed adhesive

If the tiles/stones are uncalibrated, a thick bed
adhesive must be used. This will also allow for some
irregularities in the substrate.
Ensure that any loose or unsound material is removed.
Fix the tiles with
thick bed adhesive.





Solution 3:
Use a patch repair mortar

For occasional deep holes in an otherwise flat surface,
a repair mortar may be the best option.
Ensure that any loose or unsound material is removed
and that the edges are cut square, not feathered.
Fill the hole with appropriate mortar
. Allow the
mortar to cure.
Fix the tiles using a
cement-based adhesive that
is appropriate for the type of tile.
Allow the adhesive to cure fully before grouting the

joints.








 
External Tiling



Problem

Exterior tiling is exposed to more aggressive conditions than interior tiling. The effects of sun, wind, rain, and frost combine to shorten the life of an installation, by exposing it to a continuous onslaught of a number of mechanisms.






13070_img.jpg




Most cement-based products including grouts and adhesives, are porous to some extent.

They have minute voids left by the evaporation of un-combined water or by gaps between the aggregates.

These pores allow water to permeate through the grout into the adhesive and substrate.


13072_img.jpg








Water expands on freezing and in doing so in a confined space, generates enormous forces. In cold climates the cumulative effect of repetitive cycles of freeze (expand)/thaw (contract) causes rocks to fracture. This action, known as frost shattering is part of the mechanism for weathering.

For tiling this has several implications: Pores in the grout will be vulnerable to frost damage. Any voids behind the tile provide a possibility for water to gather and then on freezing, push off the tile.


13074_img.jpg








Interior tiling situations tend to be maintained at more or less constant temperatures. Exterior installations, however, are exposed to much larger cyclic temperature swings.

With changes in temperature different materials expand and contract at different rates. When they are fixed rigidly together this causes stresses to build at the interface between the materials. If the stress gets high enough it can exceed the force that binds the two materials and delamination occurs.





Solution


Use polymer-modified cement-based adhesives


A cement-based adhesive must be used for exterior work. Whilst standard cementbased tile adhesives are suitable for exterior use, highly polymer-modified adhesives offer enhanced bond strength, reduced porosity and therefore better resistance to frost & greater resistance to movement (thermally induced movement is inevitable particularly for walls). Tiles recommended for exterior use will often be fully vitrified and these also require a higher specification for the adhesive.


A suitable SPF or rapid SPF is recommended for exterior walls and floors, both of which are highly polymer-modified. Alternatively, a suitable 2 part adhesive. It is very important that a solid bed of adhesive is achieved behind the tiles to prevent water collecting and this is easiest to achieve by back buttering the tiles in addition to spreading adhesive on the wall. It is good practice to occasionally remove a tile during fixing to ensure that the appropriate contact is being achieved. If tiles are large, heavy or being fixed above first-floor height (3m), they must also be mechanically fixed.



Construction requirements


Any movement joints in the building structure must be carried through the tiling layer and intermediate flexible joints included at suitable intervals.



Grouting


As with adhesives, highly polymer-modified grouts are more durable due to their reduced porosity, higher strength and resistance to flexing.

Ensure that the joints are completely filled with grout and tool the surface to obtain a closed surface texture. Protect the top edge of the highest row of tiles from water ingress.






 
Tiling onto balconies



Problem


Balconies can be difficult substrates to tile. The substrate and tiles will be subject to many extremes of weather from high temperatures in the summer to freeze/thaw cycling in the winter. Dark tiles will heat up quicker and to greater temperatures thus creating greater stresses. Larger tiles will also create greater stresses than smaller tiles. Without the correct design and application, the tiles are likely to debond or crack.






13126_img.jpg




The balcony should be designed in such a way that there is a slope to allow drainage. Water should not be allowed to pool.

The structure must be strong enough to support the expected load including tiles, adhesive, grout and a screed if needed, without undue movement.

Wooden balconies are not suitable for tiling.


13172_img.jpg








Balconies will receive a full array of weather conditions from freeze/thaw in the winter to direct sunshine in the summer.

Screed or adhesive that is constantly saturated with water will freeze and expand causing it to break up.

Direct sunlight onto tiles will cause them to warm up and expand causing stresses to form between the tile, adhesive and screed.


13174_img.jpg








External grade asphalt should not be tiled directly onto. The asphalt is not a stable base as it is very soft and malleable. Due to the oils naturally present in the asphalt, it is also very difficult to adhere to.




Solution




Use polymer-modified adhesives and grouts


The existing design of a balcony should be of rigid concrete construction with a gradient of 1.5mm/m towards drainage points. The construction should be capable of withstanding the extra load of adhesive, grout and tiles (consult a structural engineer). Polymer-modified adhesives and grouts offer better adhesion strengths and reduced porosity. Therefore, they offer greater resistance to frost and thermally induced movement. Dark coloured tiles absorb more heat than light coloured tiles and therefore experience greater thermal movement. Smaller tiles create less stresses than larger tiles.


1: Preparation


The surface of the balcony should be flat,
slope towards drainage points and be free
from dust, grease or any other
contaminating layer. Any existing loose or
damaged tiles should be removed and the
resulting hole filled with a suitable material
and allowed to cure. Balconies with an
asphalt residue can only be tiled when an
uncoupling membrane is used between
asphalt and tile adhesive.




2: Uncoupling and
waterproofing


An uncoupling membrane should be fitted
to the balcony so that it runs 30mm up
surrounding balcony walls and overlaps the
edge of the balcony by the same amount.
Gaps between sheets of uncoupling
membrane should be sealed with a
waterproof tape. The fitting of a gutter
should be considered at the balcony edge to
prevent dripping.



3: Fixing and grouting



Fix the tiles using a suitable
SPF or a

rapid set SPF, leaving grout joints at least 3mm
wide and ensuring that a solid bed of
adhesive at least 3 mm thick is achieved. It is
good practice to occasionally remove a tile
during fixing to ensure that the appropriate
contact is being achieved. A movement joint
of approximately 6 mm should be left at all
internal corners to allow for thermal
movement. Grout the tiles with a suitable flexy grout.




4: Protecting against water ingress​





A layer of skirting tiles should be fixed along surrounding walls and the

top edge should be protected by a waterproof trim to prevent water
ingress. A gap of approximately 6 mm should be left at the bottom of
the skirting tile to allow for movement.


 

Advertisement

Weekly Email Digest

Back
Top

Click Here to Register for Free / Remove Ad