Tile adhesive is typically composed of a rubber-based powder that's combined with a water-based polymer dispersion liquid, and is used to form a bond between a tile and a surface. Available in many different types, tile adhesives can vary in terms of their composition and recommended application, but generally speaking they are appropriate for bonding tiles to almost any kind of base, including: brick, concrete, rendering, blockwork, plaster, plasterboard, painted walls, epoxy coatings, tile backer boards, steel, floorboards, plywood, chipboard, vinyl, ceramic, natural stone, and asphalt.
When choosing the best tile adhesive for your project, there are a number of factors to consider. First of all and perhaps most obviously, consider the quantity you need. Tile adhesive is available in many different sizes generally ranging from smaller 3kg tubs, to larger tub sizes of 20kg. A general rule of thumb is to estimate approximately 2kg per m2 (this is for a depth of 1mm). Therefore, by calculating the total depth you require your adhesive to fill – let's say 5mm for example – you multiply this by two (for the number of kilograms) and then again per m2 of coverage required.
Tile adhesive can vary in terms of colour and type of application. It's important to take into account the surface you're tiling onto, and also the kind of tile you're laying, as this will affect which product is most appropriate for your job. When laying natural stone tiles for example, which by nature may have a level of transparency to them, it's important to use a tile adhesive with a colour that will not ‘stain' the tile by showing through after being laid. In this instance, it would be advisable to use a white adhesive. You can also choose between adhesives that offer extra flexibility, quicker setting times, and improved performance when bonding on specific materials such as wooden floors.
Applying tile adhesive requires the use of specific tools to achieve what's known as a ‘solid bed' for your tiles to sit on top of. The most common and useful tools in applying adhesive are tiling trowels and finishing profilers. It is useful to use a trowel appropriate for the type of tiles and adhesive you are using – for example, when laying large tiles you can use a trowel with a larger notch size to create deeper and wider ridges in the adhesive. Alternatively, if you are laying mosaic tiles, it's recommended that you use a mosaic trowel, which will feature much narrower notches to promote extra texture on a smaller given space. You may also wish to use a profiling tool to apply a more detailed finish to your adhesive, or to re-touch areas that may need further attention.
Mixing your tile adhesive is a simple enough job, and is best done using an electric mixer or an electric drill with a mortar-mixing paddle. It is important not to mix your adhesive too rapidly – under 300rpm is recommended – as it may otherwise encourage unwanted air pockets to become trapped in the mixture. You may also find that purchasing a dedicated mixing bucket will help to mix the correct quantities and reduce wastage. It is also advisable to allow the adhesive to rest for 5-10mins before applying it, as this can help to encourage any un-dissolved powder to mix effectively.
Most tile adhesives will set within 24 hours, although, rapidset tile adhesive can set within 2 hours. Bear in mind that setting times function as guidelines and that the actual setting time may differ depending on the temperature of the environment you're working in (higher temperatures generally reduce setting time, and colder temperatures generally increase it).
