Some of you must question what is meant by a flexible cementitious product. It really sounds like a contradiction in terms; is sand and cement really flexible? Martin Cummins, Ultra Floor Technical Sales Manager explains what is really meant when referring to the flexibility of cementitious products used in contract flooring i.e. smoothing and levelling compounds.

When the words flexible or flexibility are used as a unique selling point for a sub-floor preparation product they are referring to that fact that the product can accomodate some deformation and/or vibration of a floor without wholesale failure and debonding. Both occur quite often when the substrate type is timber, or a mezzanine is being created or refurbished. A truly flexible product will perform on such substrates by 'flexing' with the substrate; any others will not - consequently cracking and debonding causing failure. Similarly a sub-floor undergoing deflection cannot be prevented from moving by simply smoothing over. The floor must be made inherently stable first.


So what is in the makeup of a product that allows this 'flexing' to occur? There are essentially three separate characteristics, of which each can ensure the 'flexibility' required for the above named types of substrate.

1. A low strength product, more often than not, a latex

2. Excellent adhesion from high polymer content will help ensure that a compound stays bonded and intact, with any floor movement

3. Adding fibres to the formulations of smoothing compounds reinforces their flexibility

Essentially flexibility in terms of smoothing compounds should be defined as:

"The ability of a compound to remain bonded to a sub-floor under deflection and or vibration."

Always be prepared to question the use of flexibility in a product's marketing communication. With the number of products available and their varying uses it is important to understand terminology correctly.

When mentioning flexibility in association with a traditional latex bag and bottle, the explanation is a soft low strength product or that it has a high polymer content. Fibre reinforced feathering or smoothing compounds are ideal for use over timber.

To read a full in-depth version of this article, please visit www.ultra-floor.co.uk or call 01827 871871 to request a copy.