When selecting tiles for a project, most of the thought process tends to revolve around the appearance of the tile, plus its properties, such as the level of slip resistance provided.
However, selecting the correct tile adhesive is also crucial to a successful tiling installation.
As a bonding agent, tile adhesive is used to fix tiles securely to surfaces such as floors and walls or countertops. Its job is to create a strong and durable hold between the tile and the substrate.
Tile adhesive is commonly used for installing ceramic, porcelain or stone tiles in both residential and commercial settings, providing stability and helping tiles stay firmly in place over time.
The wrong product can lead to premature failure, debonding or costly remedial work, particularly in demanding commercial environments.
To ensure your next tiling project is a success, the Parkside team are here to explain the main tile adhesive types available. Crucially, we'll cover when each one should and shouldn't be used.
Ready-Mixed Adhesives (Paste)
Pre-mixed adhesives require no on-site preparation and are applied directly from the tub. They are best suited to wall tiling with lighter ceramic tiles in dry internal environments. Some of the most common applications include domestic kitchens and bathrooms.
It's important to note that ready-mixed adhesives are not appropriate for floor tiles, natural stone, large format tiles or any area subject to prolonged moisture exposure. Their convenience comes with significant limitations, meaning they are rarely the right choice for commercial work.
Cementitious Adhesives (Powder Based)
Powder based cementitious adhesive is the most widely used adhesive type in UK tiling. Mixed with water on site, cementitious adhesives are available in standard, improved and high polymer-modified formulations.
They are classified under BS EN 12004 as C1 (normal) or C2 (improved), with additional designations indicating extended open time (E), fast setting (F) and reduced slip (T).
C2 adhesives are the minimum recommendation for most commercial applications.
This type of adhesive is suitable for walls and floors across a wide range of substrates including concrete, sand and cement screeds and tile backer boards.
Epoxy Adhesives
Epoxy adhesives offer exceptional bond strength, chemical resistance and durability. This makes them the preferred choice for commercial kitchens, food production facilities, laboratories and other chemically aggressive environments.
They are available as two-part or three-part systems consisting of a resin, hardener and in some formulations a cement filler.
In some systems, epoxy tile adhesives can function as both adhesive and grout, simplifying the specification. However, the trade-offs are a more demanding application process, faster working times and a higher material cost.
Correct surface preparation and temperature control are essential when using epoxy as an adhesive.
Rapid-Setting Adhesives
Rapid-setting tiling adhesive is a variation of cementitious adhesives. However, it is formulated to achieve handling strength within hours rather than the standard 24 hour cure period.
This type of adhesive is useful where project programmes are tight or where areas need to return to use quickly, with retail refurbishments and transport environments being common examples.
Available in both C1 and C2 classifications, additional care is required when using rapid setting products, as reduced open time demands a faster and more experienced application.
Flexible Adhesives
Granted, ‘flexibility’ is a property of tile adhesive rather than a distinct product type. However, adhesives that offer flexibility are essential where differential movement is anticipated. For example, over underfloor heating, timber substrates, large format tiles or external applications subject to thermal expansion and contraction.
Flexibility within a tile adhesive is achieved through polymer modification of cementitious adhesives and is indicated by the S1 (deformable) or S2 (highly deformable) designation under BS EN 12004.
In commercial settings, a C2S1 or C2S2 adhesive is the standard minimum specification for most floor applications.
Large Format Tile Adhesives
Again, tile adhesive for large format tiles doesn’t relate to a specific product. However, it’s worth mentioning due to the fact that tiles above 60cm in any dimension place greater demands on the adhesive bed. This is because of their weight, rigidity and reduced tolerance for substrate imperfections.
A highly polymer-modified C2TE or C2S1TE adhesive is typically required for large format tiles.
The installation technique for large format tiles can also differ from the installation of smaller tiles. In particular, back-buttering the tile in addition to combing the substrate is standard practice to ensure full coverage. A minimum of 95% coverage is required under BS 5385 in wet areas and for external applications.
External Adhesives
Tiles installed externally must contend with freeze-thaw cycling, wind loading and significant thermal movement.
Adhesives for external use must achieve the S1 or S2 deformability classification and be frost resistant. The substrate, movement joint provision and tile selection all need to be compatible with the adhesive system chosen.
BS 5385 Part 2 covers external wall tiling and provides detailed guidance on the required specification.
Understanding The BS EN 12004 Classification System
If you are involved in a commercial tiling project (i.e. planning, design, installation or procurement), then you should know that commercial tile adhesive is also subject to stringent requirements.
When reviewing UK adhesive datasheets, the classification string gives a concise summary of product performance:
- C - Cementitious adhesive
- D - Dispersion adhesive (ready-mixed)
- R - Reaction resin adhesive (epoxy)
- 1 or 2 - Standard or improved performance
- E - Extended open time
- F - Fast setting
- T - Reduced slip (non-sag)
- S1 / S2 - Deformable / highly deformable
A product labelled C2TES1, for example, is an improved cementitious adhesive with reduced slip, extended open time and deformability. This makes it a robust all-round specification for most commercial floor and wall applications.
This framework should give any specifier, contractor or facilities professional a general understanding of which adhesive type is appropriate for a given substrate, tile and environment.
As leading commercial tile specialists in the UK, our technical advisors here at Parkside can also help you ensure that both your tile and adhesive selection meet the required specifications for your project.
Please call us on 0116 276 2532 or visit one of our design studios for tailored advice.
The Risks Of Choosing The Wrong Tile Adhesive
Any competent tiling contractor should have a comprehensive understanding of the tiling adhesive that a project requires. Also, whether specific application techniques are needed to ensure compliance with health and safety, not to mention a high standard of finish.
That said, we thought we’d take this opportunity to explain some of the problems that can occur when the wrong adhesive is used for the job.
The key point to note is that adhesive failure is almost always preventable. Furthermore, the BS EN 12004 classification system exists precisely to make the correct specification straightforward.
The cost difference between a standard and a correctly specified adhesive is marginal relative to the total project cost. It’s also often negligible compared to the cost of putting it right.
When you choose the correct tile adhesive for your project, you’ll stand the best chance of avoiding the following issues.
Tile Debonding & Hollow Spots
The most common consequence of under-specified adhesive is loss of bond between the tile and substrate. This manifests initially as hollow-sounding tiles when tapped, which is a sign that the adhesive has failed to maintain full contact. Left unaddressed, debonded tiles become a trip hazard and will eventually crack or lift entirely. In high traffic commercial spaces, this can happen rapidly once the bond begins to fail.
Cracked Or Broken Tiles
Where an adhesive lacks sufficient flexibility for the substrate, differential movement between the tile and substrate generates stress that the tile absorbs rather than the adhesive. The result is cracking, often in a pattern that follows the grout joints or runs diagonally across the tile face. This is irreversible and requires full strip-out and reinstatement.
Grout Joint Failure
Adhesive choice affects the behaviour of the entire tiled assembly, including the grout. Where movement has not been adequately accommodated by the adhesive, grout joints crack and open up. Water then penetrates the assembly, accelerating further failure and creating hygiene risks in food service or healthcare environments.
Substrate Damage
In wet areas, failed adhesive and cracked grout allow water ingress into the substrate. Over time, this can saturate screeds, cause efflorescence, undermine timber substrates and in severe cases damage the structural slab. Remediation at this stage is significantly more disruptive and expensive than the original installation.
Adhesive Slump On Walls
Using a non-anti-slip adhesive on vertical surfaces (particularly with heavier tiles), can cause tiles to slide during installation before the adhesive sets. This affects alignment and in worst cases, leads to tiles falling from the wall entirely. On large commercial wall installations at height, this becomes a serious safety issue.
Hygiene Failure
In environments cleaned with industrial products such as commercial kitchens, healthcare settings or food production environments, a standard cementitious adhesive not rated for chemical exposure will degrade over time. The adhesive bed softens, bond strength drops and the tiled surface becomes impossible to clean effectively. This directly compromises food safety and infection control standards.
Thermal Failure Over Underfloor Heating
A non-flexible adhesive over an underfloor heating system will not accommodate the repeated expansion and contraction of the tile and screed. Bond failure is typically progressive, often starting at the edges of a field and working inward over successive heating cycles. By the time it becomes visible, the majority of the floor may need relaying.
Health & Safety Issues
In commercial settings this is where the consequences become most serious. A debonded or cracked tile in a public space that causes injury can expose a business to claims under the Occupiers Liability Act 1957. If it can be demonstrated that the installation did not meet BS 5385 or that an inappropriate adhesive was specified, both the contractor and specifier face potential liability. In healthcare or food service environments, regulatory consequences may follow if tiled surfaces fail to meet hygiene standards.
Cost Of Remediation
Strip-out and reinstatement of a failed tiled floor or wall in a commercial environment is rarely straightforward. The cost of materials is often the smallest part, as access, disruption to operations, waste disposal, subfloor repair and labour typically make remediation three to five times more expensive than getting the specification right in the first place. In occupied premises such as hotels, hospitals or retail units, the indirect costs of closure or restricted access can exceed the direct remediation cost.
Need Further Advice About Tile Or Adhesive Specifications For Your Commercial Project?
When planning an architectural or design project involving tiles, it pays to get expert advice about all of the specifications your tiles must meet.
At Parkside, we have technical advisors to help our clients ensure their tile selections are fully compliant, while also meeting the desired aesthetic appeal for their commercial space.
On our website, you’ll find a range of wall and floor tiles covering different styles, from wood effect tiles to stone effect tiles and much more.
But we can also go further by giving you personalised advice about your project.
Please get in touch or call us on 0116 276 2532 to speak with our tile technicians.
If you would like to view our tiles in person, we invite you to drop into any of our tile design studios located in London, Manchester, Leicester and Glasgow.
