Choosing the Optimum Smoothing Compound with F. Ball

Choosing the optimum smoothing compound

The application of a suitable floor smoothing compound helps to ensure a surface that is free of imperfections for the installation of floorcoverings. While formulations with specialist features are often advantageous, or even highly recommended, general-purpose options should be the ‘go-to’ for many situations, explains Neil Sanders, technical director at F. Ball and Co. Ltd.

F. Ball recommends the application of a smoothing compound as part of any flooring installation to create a smooth base to prevent subfloor imperfections affecting the appearance of the finished floor, as well as optimising the bond between the flooring adhesive and the subfloor.

Our technical service department will often advise flooring contractors to consider using a specialist smoothing compound. These products have been developed to provide a long-lasting, professional flooring finish, as well as to optimise the installation process, in particular situations.

Fast-track applications

Examples of when it will be advantageous to use a specialist smoothing compound include working to tight timescales.

The fastest-drying products are walk-on hard from just 30 minutes after application and ready to receive floorcoverings in as little as 45 minutes later. Another development that has sped up subfloor preparation is the arrival of smoothing underlayments that can be applied directly over old adhesive residues, eliminating the need to spend valuable time mechanically removing them.

When it comes to preparing floors that will be subject to heavy loads or high levels of foot traffic, a heavy-duty smoothing compound should be selected for its high compressive strength, which will ensure that installations can withstand this kind of treatment for years to come.

Other situations

The application of a smoothing compound that is designed to accommodate slight movements or flexing in the subfloor is recommended when working over subfloors of steel. These products are reinforced with tiny fibres that maintain the integrity of the smoothing compound when subject to minor subfloor movement as a result of normal foot traffic or temperature fluctuations.

When working over electrical wired or water-fed underfloor heating systems that are increasingly installed over subfloors as part of new build or refurbishment projects, it is advisable to allow at least 15mm of a special-purpose smoothing compound above the pipes to avoid hotspots and ensure its structural integrity.

Efficient solutions

Where contractors are working over subfloors in a good condition, perhaps in multiple areas, such as new-build developments, and they don’t require advanced features, such as suitability for use over adhesive residues or flexible substrates, general-purpose smoothing compounds are often the best choice. Apart from being a cost-effective option, the ease with which some formulations can be applied helps flooring contractors to work quickly and efficiently.

Initial preparations

Before a smoothing compound is applied, always make sure that the subfloor is suitably sound, smooth and dry enough for the receipt of subfloor preparation products and floorcoverings. This should include the removal of any surface contaminants. There are also situations where additional preparations, such as the application of a repair compound, will be required to achieve a perfectly smooth base – where sand/cement screeds are mechanically damaged, for example.

A subfloor moisture test should be undertaken as part of any flooring installation. Where relative humidity (RH) levels within the subfloor are above 75% (65% if installing bonded wood floorcoverings), the application of a waterproof surface membrane will be required to prevent excess subfloor moisture attacking adhesives and floorcoverings, potentially leading to floor failure. The application of a primer is also recommended in almost all circumstances prior to installing a smoothing compound.

After these steps have been undertaken, the application of an appropriate smoothing compound is the final stage in the subfloor preparation process before new floorcoverings can be installed.

Support available

F. Ball’s technical service department is on hand to answer questions about subfloor preparation and floorcovering installation, including the best smoothing compound for a particular situation. They are contactable by phone, as well as by contact form and a new live chat facility on F. Ball’s recently redesigned and relaunched website.