This month Jim Percival, technical director at Palace Chemicals, considers the different types of trowels and their applications for different tiling projects.
A tiling project can fail unless the right tools – and most importantly the right tiling trowels – are used for the job.
The essential purpose of the tiling trowel is to spread adhesive evenly, ensuring a strong, full bond between tile and substrate. Trowels typically have a flat metal blade made from hardened or stainless steel, though other materials can also be used. Stainless steel is the most popular choice because it’s durable and resistant to rust. Carbon steel blades are also common and very strong, but they can rust if not cleaned properly. Some trowels are made from lightweight, rust-free materials such as plastic. The trowel will feature notches on one or more sides to create consistent ridges. The ribs formed in the adhesive allow air to escape when the tile is pressed into it.
Cheap trowels are to be avoided – they’re sometimes single use only. Any trowel will have a limited life and should be replaced when the notches become rounded, the blade is bent, or the handle becomes loose, as this impacts the consistency of the adhesive bed.
It is not the case that one type and size of trowel is suitable for all tiling applications. In fact, a professional tiler may have 10 – 15 different trowels in their toolbox.
Square-notched trowels are the most common type and are used mainly for wall tiles, porcelain and larger, thicker tiles, as they provide high coverage.
U-notched or half-moon trowels are specifically designed for floor tiling, especially large-format tiles and natural stone. That’s because the rounded ridges allow for easier collapse without trapping air, which is crucial for achieving 95-100% coverage.
V-notched trowels are used for smaller, lighter tiles, such as mosaics and small wall tiles (under 100mm), as they apply less adhesive.
Margin trowels are small, rectangular tools used for applying adhesive into corners and other tight spaces, or for detailed, small-scale work.
Notch size (width x depth) is also important, as that determines the amount of adhesive applied. As tile size increases, so should the notch size to ensure proper coverage and avoid voiding. But it’s important to note the maximum thickness of the adhesive being applied, as some adhesives are only to be used on thin bed applications.
For small tiles (<100mm) a 3mm – 4.5mm notched trowel is suitable. For medium tiles of 100-300mm a 6mm – 8mm notched trowel should be used and for large tiles of 300mm or greater a 10mm to 12mm notched trowel is best.
Jim Percival – Tiling technical manager at Palace Chemicals
www.palacechemicals.co.uk
