Gary Haigh, training and technical support manager at ARDEX Group, explains why smoothing and levelling compounds
Smoothing and levelling compounds are designed to eliminatesurface irregularities on both new and existing subfloors, creating a flat, even surface ready for additional proprietary products such as uncoupling systems, the tiles themselves or other floor coverings.
Available in one-part and two-part systems, these products are easy to mix, simple to apply, and self-smoothing—flowing naturally to form a consistent, high-quality finish.
Successful application begins with thorough subfloor preparation. The surface must be clean, dry, sound, and free from dust, grease, or any contaminants that could hinder adhesion. New concrete or screeds should be allowed to fully cure/dry in line with manufacturer instruction or industry standards.
Where subfloors are directly in contact with the ground, an effective damp proof membrane, such as ARDEX DPM 1C, is essential to prevent moisture-related issues.
For most, dry subfloors, correct priming is another critical step. Priming ensures maximum product performance through hydration, extends the “wet edge” and increases the flow, ensuring the best possible surface finish.
Mixing should always follow the manufacturer’s instructions.
Once mixed, pour the compound onto the prepared floor and spread it evenly using a steel trowel, pin or cam rake. Work thoroughly into edges and corners, blending each section as you go to maintain a uniform surface finish.
Finally, using spikes rollers (product depending) can also improve the final surface finish by breaking the surface tension of the product, removing minor imperfections left by the trowel or rake, and allow any trapped air to expel via the surface. It is important to choose a roller with a suitable pin length, based on the thickness of application.
Drying times vary by product – and be wary of the difference between setting and fitting times – particularly if fitting LVT. Be aware that many smoothing and levelling compounds available within the flooring and tiling industry, may advise a walk on time of mere hours, but the fitting/fixing may be in excess of 72 hours.
There are of course, rapid setting options such as BAL Level Fast or ARDEX K 55 Fast that can be tiled in as little as 45–60 minutes. For thicker applications, products such as BAL Level Max can be applied from 2mm up to 80mm in a single pour and tiled after just four hours, with ARDEX K40 HB from 3mm to 40mm and tiled in as little as 2 hours (at 40mm).
It’s important to note that most levelling compounds are not designed as final wearing surfaces and should be covered. For challenging substrates—such as bitumen, steel, or damp concrete—specialist solutions like ARDITEX NA or BAL Level Plus with BAL Level Plus Liquid – are recommended. Likewise, for timber or heated screeds, fibre-reinforced products provide the flexibility and durability required.
