From our experience it's clear that most tilers favour a powder adhesive, and whilst both varieties have their advantages and disadvantages, each is best suited to slightly different projects. The real difference is in the chemistry of how the products dry. But what does that mean in practice?
Ready-mix adhesives dry by evaporation
Ready-mix adhesives dry a bit slower than powder adhesives, due to the evaporation process, so while it may have the convenience factor, it can have its limitations. The way it dries makes it unsuitable for tiling onto floors or for porcelain tiles. This is because it relies on the air to dry, whereas cementitious powder tile adhesives dry chemically.
Ready-mixed adhesives are ideal for tiling areas such as kitchen splashbacks where the levels of moisture are lower, but you may need to check if suitable for use in wet areas. These tile adhesives are ideal for smaller projects as you can just pop the lid off and start tiling – great for quick jobs that don't need a more versatile adhesive.
Powder adhesives dry chemically
Powdered adhesives come in various grades and dry as a chemical reaction takes place after mixing. Suitable for most tiling jobs and types of tiles — including ceramic, porcelain and natural stone, as well as larger tiles — powder tile adhesives can also be used in wet areas such as bathrooms or wet rooms.
Unlike ready-mix tile adhesives, powdered tile adhesives can be used for tiling floors, and are suitable for use outdoors, which means you can also lay paving or patios. With flexible varieties available, these types of adhesives are suitable for tiling over underfloor heating, or in areas where movement is expected.
What's more, with new innovations such as Low Dust Technology™, Weber powder adhesives are safer and more convenient to use than ever.
Classifications for tile adhesives
Whether you're working with ready-mix or powder adhesives, there's a method of classification that means it's quick and easy to choose the right adhesive for the job.
Normal or improved cementitious (C)
C1 (normal cementitious) and C2 (improved cementitious) classifications refers to the strength of powder adhesives.
Normal or improved dispersion (D)
D1 (normal dispersion) and D2 (improved dispersion) classifications regards the strength of ready-mix adhesives.
Extended open time (E)
E classifications are used for tile adhesives which have an extended open time, meaning the product won't start to set too quickly after being spread with a notched trowel – useful for larger jobs.
Fast setting adhesives (F)
An F classification refers to a tile adhesive which is fast-setting in nature, this is useful when tiling in lower temperatures where the setting process may take longer, or where there is a tight deadline.
Improved flexibility (S)
Flexible tile adhesives are denoted with two classifications: S1 (improved flexible tile adhesive) and S2 (ultra-flexible tile adhesive), which are suitable on substrates which are subject to deflection and movement.
Reduced slip (T)
T classifications refer to tile adhesives which have reduced slip – useful for applying larger or heavier tiles onto walls, keeping them firmly in place throughout the tiling process.