It’s no secret that knowing when to opt for a powdered adhesive over a ready-mixed tile adhesive can be confusing.
Here Dunlopman shares his tops tips for correct product selection.
It’s an age-old predicament, can I use a ready-mixed tile adhesive, or should I go for the conventional cement-based powdered tile adhesive?
The truth lies behind how the product dries. Ready-mixed is generally easier to use as it can be spread straight out of the bucket and does not require water or mixing (hence the name). While ready-mixed adhesives (e.g Dunlop RX range) are perfect for fixing 300x300m ceramic tiles or metros, at Dunlop we would never recommend using such a product when using porcelain, large-format tiles and tiling floors or wet areas.
This is because the drying chemistry behind a ready-mixed product doesn’t function well within these environments as it requires a greater amount of water evaporation.
If you think about the product itself, it’s already wet, meaning the moisture levels in the adhesive are significantly higher than in a powdered product – resulting in longer drying times and a greater need to have access to air for moisture evaporation.
Take porcelain tiles for example: they have a non-porous surface, which reduces access to air. If they were attached to a surface using a ready-mixed adhesive, the middle of the tile would remain wet and fail to attach. This is called picture framing. The result can be disastrous, leading to unnecessary expense and time wasted, as the tiles will initially attach but are then at risk of coming loose or cracking when the adhesive fails to fully dry.
The same premise is also applicable to large-format tiles. Again, the larger surface area reduces access to air for moisture evaporation, and as any builder and merchant will know, these tiles are heavy. The result of a large-format tile failing to stick isn’t just costly and time consuming; it’s potentially dangerous – especially if the tile is fixed above shoulder height.
The same rules apply to the environment in which a tile is being used. If it’s a wet environment, there is an inevitable reduction in moisture evaporation, meaning the tiles will never fully dry and fix. When applying tiles to a floor, professional builders will need to consider that impact and movement is greater than on a wall. If a tile has been fixed using a ready-mixed adhesive, the likelihood of cracking is increased, as the surface beneath may still be wet – weakening the tile and increasing the chances of slipping or cracking.
Although ready-mixed is generally cheaper and easier to use, it is worth investing a few extra pounds into a powdered tile adhesive (e.g Dunlop Flexible Rapidset Tile Adhesive) for such jobs. Powdered tile adhesives use a different drying chemistry. This provides added flexibility when it comes to the hold and drying consistency, helping the product to dry throughout, rather than in just the exposed areas.
Powdered adhesives are ideal for large-format, natural stone and porcelain tiles and help to adhere a tile to floors and wet environments. The added strength, flexibility and drying consistency are absolutely essential to ensure a quality and long-lasting hold.
Powdered cement-based tile adhesives also provide significant time savings to builders as they can be grouted quicker than ready-mixed tile adhesives. For example, Dunlop Flexible Rapidset Tile Adhesive can be grouted after only 3 hours (at 20°C) while a ready-mixed adhesive (such as Dunlop RX 3000 Waterproof Wall Tile Adhesive) may take up to 24 hours to dry and be ready for grouting.
In short, always question the environment that is being tiled and the tile type being used before advising on a ready-mixed over a powdered adhesive. This will save you time, money and a lot of hassle, ensuring you get a quality result from start to finish with peace of mind that the job has been delivered to the highest of standards.