Tiles convince not only through functionality and comfort, but also through their appearance. To keep it that way as long as possible, regular cleaning is of course indispensable. In the following article, we will give you useful information and practical tips on how to effectively remove various smaller and larger stains from your tiles.

Tiles are extremely hard-wearing and robust. No wonder that they are particularly popular where walls and floors are in great demand. However, dirt, stains and deposits cannot be avoided, especially under heavy use. And over time, this can leave its mark on even the most grateful tiles.

The bad news in this context: To keep your wall and floor tiles clean or to make them clean again, you unfortunately have no choice but to clean them. But the good news is that tiles are basically quite easy to clean.

Tile cleaning: Simple, but with certain differences

Generally speaking, cleaning clay tiles does not require much. They are generally very easy to clean and can usually be kept in good condition with a vacuum cleaner, cloth and clear water.

Most tiles are also quite resistant to cleaning agents. Most, but not all. With ceramic tiles, you can in principle use all common products without hesitation. However, anyone who wants to clean unglazed porcelain stoneware tiles should make sure that they do not contain any surfactants. Tiles made of natural stone, on the other hand, are the famous exception to the rule: The sensitive surface needs particularly gentle cleaning and should, if at all, only be treated with special cleaners.

In addition to the material of the tiles, the type of dirt also plays a role. On the one hand, in terms of the effort involved and on the other hand, how best to deal with the dirt. So it makes a difference whether you are dealing with everyday dust and conventional street dirt in the hallway, grease splashes in the kitchen or stubborn lime stains in the bathroom.

Tips from A for all-purpose cleaner to Z for toothbrush: How to clean tiles properly

In other words: Tiles are not the same and dirt is not the same as dirt. This makes it all the more important to have the optimum procedure, the suitable cleaning agents and aids or the best household remedies for every application. And the following tips should help you do just that.

First basic cleaning: Cleaning of tiles after laying

The first step for beautiful and clean tiles is a thorough cleaning after the laying work. Warm water alone can have a great effect: To remove the remains of the jointing mortar, first of all simply wipe the newly laid tiles carefully with a damp cloth or sponge.

If a grey cement veil remains nevertheless, you now have several further possibilities. For example, there are various special chemical cleaners available in the trade with which you can easily get the dirt off the tiles. However, you should pay attention to the ingredients (e.g. hydrochloric or phosphoric acid) so that the product is also suitable for the material of your tiles.

Alternatively, you can also use household remedies. Lemon juice or a mixture of vinegar essence and water can also be used to remove the cement film: simply apply to the tiles, leave to work for a few minutes and wipe thoroughly with clear water. This may require a little more effort because you may have to repeat the process more often, but it is also much cheaper and more environmentally friendly.

What is important in any case: Wait with cleaning until the joints (including the expansion joints of the tiles) are completely hardened (approx. 7 days) in order not to risk damage.

Clean floor tiles

Floor tiles are exposed to more or less high loads, depending on the area of application. Thus the degree of soiling also varies from light to heavy. And this logically requires different procedures for cleaning. But of course there are also helpful tips for each specific case (most of which can be applied to the cleaning of wall tiles):

  • The most important basic rule for clean floor tiles: Clean regularly. This means that dirt has fewer chances from the outset and the overall effort is kept within limits.
  • In case of loose dirt and dust, it is best to simply reach for a broom or vacuum cleaner as quickly as possible so that the dirt cannot spread and become stuck.
  • In addition to dry cleaning, you should of course also wipe your floor tiles wet at regular intervals. The recommendation here is usually once a week, or more often if there is heavy use. All you usually need is clean, warm water, any cleaning system (e.g. mop) and a suitable cover (ideally made of cotton).
  • Of course you can also add a few drops of cleaning agent to the mopping water. In the case of ceramic tiles, standard household or all-purpose cleaners or simple washing-up liquid are completely sufficient. You can also clean porcelain stoneware with anything, as long as it does not contain any surfactants. This is because the residues can settle in the porous surface, making the tiles much more difficult to clean over time. To be on the safe side, alkaline or acidic cleaners (e.g. acetic or citric acid) are therefore the better choice for porcelain stoneware.
  • You should generally avoid aggressive cleaning agents for tiles. On the one hand it is usually not necessary anyway and on the other hand it can damage both tiles and joints in the long run.
  • Remember to change the mopping water regularly when cleaning floor tiles so that the dirt absorbed does not get back onto the tiles and, above all, into the joints.
  • After wiping, it is recommended to dry the tiles with a microfibre cloth. This means that excess water cannot leave behind limescale stains – and the floor remains free of streaks even if too much cleaning agent is used.
  • Heavily soiled tiles are best cleaned by soaking: Apply the water-cleaner mixture generously to the affected areas and let it soak in for a few minutes before wiping your floor tiles clean as usual. Particularly stubborn stains can be additionally treated with a brush, for dried incrustations the ceramic hob scraper from the kitchen can also be useful. If all this does not help, there are still special remedies for stains in the tile trade. TIP: Do not use sharp or pointed objects or metal meshes to scrape off any dirt – they could damage the tiles despite their resistance.
  • If you generally do not feel like scrubbing, you can use a steam cleaner instead. The practical devices are ideal for cleaning floor tiles and dissolve even heavy dirt almost by themselves.
  • If you prefer natural cleaning, you can fall back on proven household remedies: vinegar, citric acid or orange peel usually remove dirt just as reliably as the considerably more expensive cleaning agents. Curd soap and soft soap are also alternatives worth considering, especially the latter is even suitable for cleaning natural stone tiles.

Cleaning bathroom tiles

In general, the same recommendations apply when cleaning bathroom tiles as in any other room. With one special feature: In the bathroom, the dirt consists mainly of lime deposits – especially where walls and floors frequently come into contact with water. Here are a few additional tips:

  • The best tip against annoying lime spots is to avoid them at first. Ideally, you should therefore remove the water from your bathroom tiles with a squeegee and/or a dry, absorbent cloth immediately after each shower. Do not forget the joints!
  • Remaining lime residues are best removed with the popular household remedy vinegar. Take the cheapest household vinegar or mix vinegar essence 1:1 with water and wipe the calcified tiles with it. Allow the vinegar to soak in for a few hours before rinsing thoroughly with warm, clear water. Tip: Since vinegar is highly acidic, you should avoid the joints as much as possible when applying the product.
  • The alternative to vinegar is lemon juice or orange peel. Simply rub the calcified tiles with it, let it take effect and rinse with clear water as usual. A positive side effect: the citrus fruits not only remove limescale, but also leave a wonderfully fresh scent in the bathroom.
  • An insider tip against lime are dishwasher tabs. Dissolve the tab completely in a spray bottle of water and spray the mixture onto the tiles. After a short reaction time of approx. 15 to 20 minutes, the lime residues should be easily removed with a damp cloth. TIP: You can achieve the same effect with denture cleanser or vitamin C tablets.
  • For heavily calcified tiles, rinse aid is also often used. When applied diluted with water (or undiluted in cases of hardness), the unsightly white stains should disappear quickly.
  • Limescale deposits on natural stone tiles are easily removed with gemstone soap. Put a little soap in warm water and wash the tiles with it. Afterwards you should wipe with clear water to avoid a lubricating film.

Cleaning tiles in the kitchen

What is lime in the bathroom is fat in the kitchen. Grease stains are a daily occurrence, especially on the wall tiles around the stove. To remove them, however, it does not take much:

  • Warm water and dishwashing detergent usually already achieve the desired result.
  • Liquid detergent also dissolves the grease and gives your kitchen a new shine.
  • Encrusted areas can be additionally treated with curd soap and brush.

Clean rough tiles

If tiles are particularly rough, dirt particles can settle more easily. But with the right tips you can also clean rough tiles very easily:

  • Microfibre cloths are very useful on rough surfaces, as the fine fibres penetrate deep into the pores and even get out deep-seated dirt.
  • With a dirt eraser you can also get rid of the dirt on your rough tiles.
  • In case of coarser dirt, it is recommended to wipe the tiles with vinegar water.
  • You can also clean heavily soiled areas on rough tiles with a versatile household remedy: baking powder. To do this, make a paste with water and apply it to the tiles. Then spray some vinegar on the paste and let it work for about 15 minutes. If necessary, you can also help with a toothbrush before you finally clean the treated area thoroughly.

Cleaning old tiles

If tiles are already a bit old, yellowing often occurs. A mixture of salt and turpentine helps to get rid of the unsightly yellow veil.

Clean matt porcelain stoneware tiles

In the course of time, tiles can become dull. Rub your tiles with ammonia or ammonia solution – and they will look like new again. You can also use rinse aid, linseed oil or hair shampoo to make matt tiles shine.

Clean joints

A not very popular (because it is much more complex), but at least as important topic is joint cleaning. Finally, here are a few valuable tips and household remedies:

  • Wipe the joints in the same way with all-purpose cleaner and a damp cloth when cleaning your tiles. In this way you keep the dirt – and the associated cleaning effort – within limits from the outset.
  • Dirty joints are made nice and clean again with a paste of baking powder and water. Simply apply with an old toothbrush, let it work for a short time and rinse off with water. Of course you can also use a special joint brush.
  • As an alternative to baking powder, you can clean the joints of your tiles with soda. The procedure is basically the same as for baking powder, as is the effect. Please note, however, that soda may cause skin irritation.
  • And you will often find another tried and tested household remedy when grouting and cleaning tiles: With baking soda you can not only remove dirt, but also prevent the formation of mould.

If you want tiles, you also need joints – and therefore sooner or later you have to find the right grout. Compared to the tiles themselves, the choice is much less extensive, but the decision is no less important. Read this article to find out what types of grout are available and how to choose the right product for your tile project at home.

The tasks of joints

There are two main reasons why grouting tiles is so important: one visual and one technical. On the one hand, joints set design accents and give wall or floor tiles their final, characteristic appearance. On the other hand, they compensate for movements of the tiles or the substrate, distribute acting forces, prevent the penetration of moisture under the tiles and ensure a hygienically closed surface. In other words: joints take over several central functions for a durable, flawless, robust and hard-wearing tile covering.

However, the decisive factor is to find the right grout for the tiles used, the existing substrate and the degree of stress in the respective area of application. After all, not every grout is equally suitable for the different requirements in terms of durability, use and load of the tiles.

What kind of grout is available?

A large number of different grouts are available in stationary specialist shops, DIY stores or online. Apart from brand and price, these differ primarily in their composition. Depending on the raw material base, jointing mortars are divided into the following categories:

Normal joint mortar / cement joints / joint white

The classic joint mortar – commonly referred to as joint white – consists of fine cement, colour pigments and fillers without a plastic content. Simple joints in tiles or slabs can usually be produced without problems and at a reasonable price with this type of grout.

However, it should be noted that the material does not guarantee water-repellent joints, which means that conventional cement grout is not recommended for tiles in damp or wet rooms . In addition, the grout made of conventional, cement-based tile mortar is relatively rigid and should therefore only be used on flexurally rigid and thus vibration-free substrates.

Flexible joint mortar / Polymer-modified cement joint / Flex joint

In principle, flexible joints are also cement grouts – but enriched with plastics. These make the grout more elastic, so that material movements and surface tensions (e.g. with vibrating substrates or temperature fluctuations) of the tiles can be compensated. In addition, flex joints are usually water-repellent and improve the tile’s flank adhesion.

This means that jointing compounds made of polymer-modified cement can be used in a variety of ways and also for more demanding applications. The areas of application range from wall and floor tiles subject to higher loads to tiles on underfloor heating systems and other problematic substrates to patio tiles or tiles in rooms subject to splashing water or wetness, such as bathrooms or showers.

Rapid jointing mortar

Wherever newly laid tiles need to be reused quickly, fast grouting mortars are often used. These grouts set within a few hours and are then both waterproof and frost-proof (partly suitable for tiles in outdoor areas). In addition, fast-setting grouts can be washed off the tiles earlier and at the same time longer, which is particularly advantageous when grouting large areas. As a rule, this type of grout is mainly used in the commercial sector, less so for private individuals at home.

High strength jointing mortar

If tiles are exposed to heavy loads, high-strength grouts are recommended. The extra-fine microcement jointing compound hardens particularly densely, then exhibits a very high abrasion resistance and is even resistant to weak acids.

Epoxy resin jointing mortar

Where even the best cement grout is no longer sufficient, expoxy resin grouts are used. They are diffusion-tight, resistant to chemicals, easy to clean (important for clean tiles with tile cleaner) and extremely hard-wearing. The solvent-free two-component joint sealants are therefore often used on complicated substrates or in wet areas exposed to water, such as swimming pools, wellness areas, commercial kitchens, laboratories, etc.

However, all these advantages are counterbalanced by disadvantages – first and foremost the elaborate processing and the higher price. But even the completely vapour-tight surface can become a problem if penetrated moisture under the tiles can no longer escape.

Grout colours: What works how?

As mentioned at the beginning, besides the functional benefit, the optical effect of joints should not be disregarded. Especially the colour play of grout – tiles can make a room look completely different. For example, a surface is generally considered to be much more harmonious when tiles and grout are colourful tone on tone, while strong contrasts are often used as a conscious element of interior design.

This should definitely be taken into account when deciding on a suitable grout. However, the colour sorting of many tile manufacturers is unfortunately not always very varied – most articles are offered in various gradations of the classics white and grey, with more and more alternatives being offered online in particular.

Even ambitious craftsmen know: tiling is not that easy. It requires craftsmanship, experience and precise execution. Otherwise, mistakes can quickly happen that cannot be easily eradicated. So if you don’t think you can do it yourself, you should probably leave the laying to a professional. The decisive question in this context is then quickly: What will the tiler cost me? The answer to this question is revealed in this article.

What are the costs of tiling?

One thing in advance: It is not easy to give a general answer to the question of how much the laying of tiles by a professional actually costs. This is because the tiler price depends on several factors and can therefore vary greatly depending on the project.

What the tiling will cost is always influenced by the following three components:

  • Material
    • which tile manufacturer
  • Workload
  • possible additional services
    • must the substrate first be levelled with a leveling system for tiles?
    • must the substrate be levelled with a levelling compound for tiles?

These costs are usually quoted per square metre, which is also the most reliable basis of calculation for you as a customer. This allows you to estimate the total cost of tiling a given area when you request a quotation.

Material costs

The tiles themselves naturally account for the largest share of the material costs. The following applies: the price differences are just as large as the selection. While simple ceramic floor tiles or promotional items are already available from 5 to 10 euros per square metre, extravagant brand-name tiles or special formats, such as mosaic tiles, for example, can also be considerably more expensive at 70 to 100 euros per square metre. On average, however, high-quality tiles usually cost between 20 and 40 euros per m2. When making your choice, make sure that the tile is suitable for the desired application. You should pay particular attention to the tile abrasion class and in the bathroom or on the terrace additionally to the skid resistance of the tiles. This may increase the costs a little bit, but the higher quality is definitely worth it in these cases.

In addition, there is also the tile mortar or tile adhesive during laying or the grout. Depending on the size of the tiles, joint width and the filling material used for the expansion joints of the tiles, the costs per m 2 for this can be between 2 euros and 11 euros.

The total cost of the material depends, of course, on the surface on which you want to lay the tiles. Because on the one hand, this determines how many square metres of tiles you need, and on the other hand, what tile mortar or adhesive is required.

You can easily calculate a guide value for the material requirements:

For a floor installation, multiply the length and width of the room, for wall tiles take instead the height up to which the tiles should be placed. Also remember to allow for about 10 percent reserve for cuttings, breakage or later repairs.

Labour costs

The choice of tiles also influences how much the laying work costs. This is because tilers calculate the estimated work required with the corresponding tile and also convert this into costs per m2. In addition to the cost of laying tiles, the prices quoted per m 2 usually also include grouting and other necessary sealing work (e.g. silicone or acrylic joints). If not, this usually adds about 1 to 2 euros per meter.

The price per square meter is influenced by several factors:

Thus, floor plans that require complex cutting of the tiles increase costs just as much as special requests or complicated patterns. In addition, glued installation is in principle cheaper than laying tiles in a mortar bed. On the one hand, even large-format tiles often mean less work and correspondingly lower costs because they can be laid more quickly. On the other hand, however, they must also be aligned much more precisely, which at the same time increases the effort required. The trend towards particularly narrow joints, often associated with large tiles, can also increase costs.

As a rule, the cost of a tiler is between 30 euros and 50 euros per m 2. However, the above-mentioned influencing factors can by all means increase the costs per m 2 by another 10 to 20 euros. In addition, regional price differences may exist: For example, tiles are generally more expensive to lay in the city than in the countryside – and the well-known West-East divide also plays a role.

Some tilers prefer, especially for complicated orders, to charge according to actual time spent instead of a price per m 2. An example of this is the laying of tiles on stairs, as the amount of work involved here is above average in relation to the area. An hourly rate of at least 40 euros is normally customary in the industry, but the costs can sometimes be considerably higher depending on the requirements or qualifications of the tilers.

Additional services

In addition to material and installation work, additional costs may also be incurred. For example, you should check whether the offer already includes the filling and priming of the surface. This is because this work is required relatively frequently and can also cost around 5 euros per square metre extra. Also the installation of edge or skirting boards usually costs around 5 euros per meter extra. Not to be forgotten are possible costs for travel, construction site equipment or transport or delivery of the tiles.

Example: Costs for 20 square meters of tiles

On the basis of the cost factors for tiling, which have now been explained, the following exemplary calculation now shows what a tiler can cost for 20 m2 :

  • Tiles (porcelain stoneware, abrasion class 2, non-slip, EUR 30,-/m2) 600,- Euro
  • Tile adhesive (permanently elastic, EUR 7,-/m2) 140,- Euro
  • Filling and priming (extra charge, EUR 5,-/m2) 100,- Euro
  • Labour costs for tilers (EUR 40,-/m2) 800,- Euro
  • Additional services (installing skirting boards, setting silicone joints) 150,- Euro
  • Journey all-inclusive 70,- Euro

Total for 20 m2 Have tiles laid 1,860.- Euro

The best saving tips when tiling

All in all, it can be quite expensive to hire a tiler. Therefore we have a few tips on how you can reduce costs:

  1. It pays to compare prices
  2. You can also save on the installation itself, for example by dispensing with elaborate installation patterns or by not selecting a joint width that is too small.
  3. Avoid billing on an hourly rate to avoid unforeseeable cost developments. Instead, it is better to agree on a flat rate if a price per square metre is not possible.
  4. In addition, you can already make some advance payments yourself, which the tiler would otherwise charge for. For example, you can prepare the substrate by cleaning, smoothing and priming it yourself.
  5. You can also do the grouting or sealing with silicone yourself. Compared to tiling itself, this is almost child’s play.

Tiles convince not only by their attractive appearance and durability, but above all by their durability. Optimum adhesion to the substrate is the be-all and end-all – and for this you need the right conditions. In this article, you will learn how to ensure that your tiles have a lasting hold and what a decisive role the primer plays in this context.

The right substrate for tiles

Whether cement, concrete, plaster or even tile on tile in the bathroom – in principle, you can lay tiles on almost any surface. The prerequisite, however, is that they are clean, dry, flat and stable.

For example, when laying a new screed, it is essential to allow time for the tiles to fall below a certain residual moisture content and for the floor to be ready for laying. While, on the other hand, when laying tiles on top of tiles, you must first create a sufficiently even surface – preferably by using tile levelling compound, which you use to cover the old tiles.

But that’s not all. Because in most cases, an optimally prepared substrate also includes the right primer.

Primer – why actually?

If we were to ask you what actually makes tiles stick, tile adhesive would probably be your first answer. Basically, this is not wrong of course – after all, you can use it to attach the tiles to the wall or floor. But then it is not quite right either. Because the adhesive alone does not provide good adhesion.

In order to ensure that the tiles actually remain permanently bonded, you must first ensure that the substrate is evenly absorbent to increase the effect of the tile adhesive or even create it in the first place. And that is exactly what the primer is for.

Which primer for which substrate?

In principle, a distinction is made between the categories of deep primer and adhesive primer. The various products, which are available in a wide range of ready-to-use products in specialist shops, differ both in their composition and in the type of surface on which they can be applied:

Deep base for highly absorbent material

Highly absorbent substrates, such as plaster or cement, draw water from the tile adhesive – with potentially unpleasant consequences during and after installation. On the one hand, the adhesive hardens faster, leaving you less time to install the wall or floor tiles. On the other hand, the adhesive effect can be impaired, which in turn leads to less adhesion of the tiles. In these cases, therefore, a pre-treatment with Tiefengrund forms the basis for a permanently perfect result when tiling.

Tiefengrund is usually a liquid primer based on synthetic resin, which is applied to the substrate diluted with water or undiluted, depending on the manufacturer’s information. It penetrates deep into the surface, solidifies the material and thus reduces its absorbency. In this way, the primer not only helps the tiles to adhere better, but also protects against too much penetrating moisture under the tiles.

Primer for smooth surfaces

In contrast, primer is used on non-absorbent or only weakly absorbent, smooth surfaces on which bonded tiles would normally not hold sufficiently.

This type of primer provides optimal conditions, especially for surfaces made of concrete, metal or even screeds made of mastic asphalt. In addition, existing tiles can also be treated with primer to ensure the necessary adhesion when laying tile on tile.

Adhesion primer consists of coarse-grained mortar with binding agents, which serves as a bonding agent between tile and adhesive. Unlike Tiefengrund, Haftgrund does not penetrate very deeply into the surface.

The best tips for an optimal primer

1. determine the absorbency of the substrate

Before priming your wall or floor, you should first test the absorbency of your substrate. With the so-called scratch test this can be tested well and easily: The easier and deeper you can prick the surface with a screwdriver or other sharp object, the more absorbent it is.

Another possibility is the water test, in which you moisten a small area of the substrate. If a dark discoloration is visible, you are also dealing with a highly absorbent material.

2. choose a suitable primer

On the shelves of DIY stores, but also in various online shops, you will find countless different products for priming. You can find out which of these is the right one for the condition of your surface from the manufacturer’s information. In addition, the primer and adhesive must be compatible. Ideally, therefore, only products of a system should end up in your shopping cart.

3. apply primer step by step

Before the primer can be applied, dust, dirt and material residues must be carefully removed from floors or walls. For the priming itself, it is best to use a paint roller or ceiling brush to achieve the most even result. Alternatively, you can also use a brush or a spray bottle.

In case of highly absorbent surfaces or larger damages, it is recommended to apply at least two coats of primer (first diluted and then undiluted) – more if necessary. Make sure that the first layer is sufficiently dry before applying the next one. All necessary information about the drying time can be found in the manufacturer’s instructions. When the primer is dry, you can start laying the tiles.

Expansion joints is the decisive keyword for a permanently beautiful and damage-free tiled floor. After all, like almost any other material, tiles need sufficient room to move to be able to work. In this article you can read about the important functions of an expansion joint, where it is required and how best to create it.

Why do you need expansion joints?

Tiles consist mainly of natural raw materials that react to external influences. Temperature fluctuations or the application of force cause the plates to work: The material expands and contracts according to the ambient conditions. However, this reaction behaviour is not a unique phenomenon of the tile, but occurs always and everywhere where different building and material materials meet.

This is exactly the point why expansion joints are so important when laying tiles. They serve as a buffer to compensate for the movements of the different materials without the components colliding with each other. At the same time, expansion joints have another function: they dampen sound because they reduce the transmission of vibrations.

What happens if the expansion joint is missing?

As low as the expansion and shrinkage behaviour of tiles may be, it can be unpleasant if expansion joints are not taken into account accordingly. Although the changes are usually barely perceptible to the human eye, they do increase the pressure on the individual plates.

This causes stresses on the surface, which in turn can cause cracks in the tiles. And sometimes not even directly where the joint is missing, but – due to the transmission of force – in a completely different place. Therefore even adjacent floor coverings or the screed can be damaged if the corresponding joints are not set.

For which tiles are expansion joints necessary?

Expansion joints – often also called movement joints, expansion joints or dilatation joints – are to be considered in principle for all tile floors. No matter whether it is natural stone, earthenware, stoneware or porcelain stoneware. Also the substrate or the tile adhesive or tile bonding primer used during installation have no influence on the necessity of the joints.

Where should an expansion joint be placed?

Specifically, expansion joints must always be created when different components come together. This primarily concerns all transitions to rooms (e.g. door thresholds) and between different floor coverings (e.g. B. tiles and parquet), but also areas which are only partially tiled (e.g. around a tiled stove or fireplace) or which adjoin rigid elements (e.g. radiators or fittings).

Edge joints as a connection area to the wall are also considered expansion joints and must therefore always be taken into account accordingly. In addition to their compensatory function when expanding, they also ensure that the impact sound is not transmitted to the wall and thus into the room. This is one of the reasons why they should be regularly maintained and checked for their condition or tightness (to protect against moisture under the tiles).

Important: Interaction of expansion joint & observe screed!

Existing expansion joints from the screed must also be taken over in the tiled floor – and in the same position. This applies both to the initial laying of tiles and slabs and to subsequent renovations. Only then can it be guaranteed that the substrate also has sufficient room to move and that the materials can work independently of each other according to their properties. This avoids cracks or fractures that could otherwise sooner or later be transferred to the tiles. Where these joints should be planned exactly is usually announced by the screed layer.

By the way: A term that also appears again and again in connection with the screed are the so-called dummy joints. Although these serve a similar purpose to expansion joints, they are not actually expansion joints. Rather, these are deliberately placed predetermined breaking points that specifically control the further course of possible cracks in the screed.

From which room size are expansion joints required?

The formation of expansion joints is regulated according to DIN standards. Accordingly, field boundary joints are prescribed for rooms with a size of 40 m2, whereby the field length and width should be between 5 and 8 m at the most. In this context, the room geometry, the tile format used and the expected stress on the floor must be taken into account. If the room has a floor heating under the tiles, the arrangement of the heating circuits must also be taken into account.

In general, the recommendation is to work in expansion joints vertically and horizontally at intervals of 3 to 6 m. For larger areas and tiles in outdoor areas, joints should be planned around every 4 m, as the expansion of the tiles can be even greater there than indoors due to higher temperature differences.

How wide must an expansion joint be?

The width of the joints depends on the tile format as well as on the respective position. The limit values recommended by the DIN standard again serve as a guideline:

Especially in the edge areas to the wall or wherever the tiles are adjacent to other rigid components, a width of 5 mm should not be undercut under any circumstances. To be on the safe side, in this case it is even better to increase to 8 mm. Professional planning and exact calculation of the joint dimensions is definitely advisable.

Excursus: Attention with narrow joints!

However, since the joint pattern in a room also has visual effects, care should be taken to ensure a balanced distribution and the most uniform width possible of all necessary joints. In particular, the continuing trend towards large-format tiles with very narrow construction joints – i.e. the distance at which the tiles are placed on the floor during installation – can sometimes become a problem.

On the one hand, because the considerably wider expansion joints can quickly look unsightly in comparison and thus disturb the overall harmonious impression. On the other hand, the narrower the joints are, the more difficult it is to grout – and improper execution impairs the quality of the joints.

If too much water is added to the jointing mortar to make it more fluid, this can lead to differences in colour and spots in the joints due to different drying phases. While too little water, on the other hand, makes the joint sealant brittle. For this reason, filling with conventional, cementitious jointing compound is only possible from a width of at least 2 mm. Among these, only highly viscous materials with a synthetic resin content can be used, as these are more elastic and can be worked into the joint more easily.

And even otherwise, very narrow joints entail an increased risk of damage. This is because if the proportion of joints is small, moisture can only escape from the floor very slowly on the one hand and on the other hand, tensions are less well balanced.

How is an expansion joint correctly filled?

In order to be able to compensate for the movements of the tiles, expansion joints may only be sealed with permanently elastic sealants. The best known and most frequently used material for this is silicone. The best possible result is achieved if the joint sealing compound is applied as deep as the joint is wide – otherwise, too deep filling can have a negative effect on the elasticity. Tip: You can work particularly precisely if the tip of the cartridge is simply cut to the appropriate joint width.

Since the silicone must not adhere to the substrate under any circumstances, expansion profiles made of foam or plastic are also recommended. These are pressed into the joint before filling and fixed at the edges with adhesive tape. Alternatively, paper strips can also be used.

Practical side effect: In this way, the material requirement is also minimized.

Before filling, dust, dirt or adhesive residues must be thoroughly removed from the joint. This is especially true when existing expansion joints are renewed: They must be carefully scraped out before the new filling material is applied.

After the joint has been sealed, the joint sealing compound is evenly removed with a smoothing trowel. Finally, the attached adhesive tape is peeled off and the excess joint sealing compound and any adhesive residues are removed with a damp sponge.