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Commercial Flooring News

Smoothing Compounds Move With The Times

Neil Sanders on flexible flooring

THIS month I will offer information and advice on flexible smoothing underlayments.
Some fibre-reinforced underlayments can ‘flex’ once cured to accommodate the likely movement of some substrates, including plywood and steel.
From plywood substrates to raised access steel panels, the flexibility of a new floor needs careful consideration in a whole host of different settings and environments.
If a traditional smoothing underlayment were to be installed over either of these subfloors, also known as ‘semi-flexible substrates’, the surface may crack due to movement in the subfloor caused by changes in ambient temperature, moisture or traffic.
Cracking can ultimately threaten the long-term performance and aesthetic appeal of a finished floor. This can, of course, lead to timely and costly remedial work.
To avoid such issues, flooring contractors should thoroughly prepare a subfloor before installing a suitable smoothing underlayment that has the ability to ‘flex’.
n Flexible properties: Flexible smoothing underlayments are specifically formulated utilising the latest technology to withstand the potential movement within a semi-flexible subfloor, while promoting the strength required to prevent cracking occurring.
The products are able to ‘flex’ due to the high polymer to cement ratio in their formulation, and the use of acrylic fibres to reinforce the compound.
These features support a flexible smoothing underlayment, ensuring it remains a strong and stable base throughout the lifetime of a floorcovering.
n Semi-flexible substrates: As a wood composite, plywood is considered semi-flexible because it is particularly susceptible to movement caused by moisture.
When working on such installations, 6mm plywood must be primed before a minimum of 3mm of a flexible smoothing underlayment is installed. This is in accordance with guidelines outlined in BS 5325 and 8203.
Furthermore, contractors may work with steel subfloors when completing projects on marine vessels, commonly fitting new floorcovering onto decking.
In these circumstances, it is importance to note that any products used during marine installations should meet the relevant standards, such as those set by the International Maritime Organisation.
n Fast track and flexible: As flooring contractors are often under pressure to complete installations to strict deadlines, F. Ball and other subfloor preparation product manufacturers, work hard to ensure that smoothing underlayments promote fast-track properties, without compromising on the floor finish.
Some flexible smoothing underlayments are ready to receive resilient floorcoverings in as little as three hours, when applied at a thickness of 3mm over an absorbent plywood surface.
Selecting a specialist flexible smoothing underlayment will ensure the best floor finish on a project involving a semi-flexible substrate.
When working with semi-flexible substrates such as steel and plywood, a specially designed smoothing underlayment, with the latest cement technologies and fibre-reinforcement is guaranteed to promote the strength and flex needed to negate cracking and provide a lasting, durable finish.
Neil Sanders is technical director for F Ball and Co
T: 01538 361633

This article has been reproduced from the Contract Flooring Journal website. You can find them at