Why do we need self-levellers and moisture barriers today if we didn’t need them 20 years ago?

by Ofentse Sefolo
Why do we need self-levellers and moisture barriers today if we didn’t need them 20 years ago?

With more than 50 years’ experience in the local and international flooring industry, Denver Coleman, Chairman of Polyflor SA, answers questions posed by installers, architects and readers. In this issue, he discusses the repercussions of modern building methods and environmental sustainability on subfloor preparation.

“There is a great deal of frustration and confusion as well as cost factor implications regarding adding a self-levelling screed and moisture barrier to the floor preparation for vinyl flooring installations. We didn’t experience the same issues 20 years ago. Why is it a problem today?” – Herman Kleingeld, Cape Town

Flooring manufacturers spend a lot of time, money and effort attending to problems with screeds, moisture and poor installation at no fault of their own products. The floor covering is actually only the decorative “icing on the top” but aesthetically dependant on good quality floor preparation.

A number of changes in the built environment have led to an increase in problematic subfloors. Some of these changes include changes in how concrete is manufactured such as the addition of chemical additives; changes in cement because the water ratio has been increased; power floating and fast-track building programmes.

Each stakeholder involved in the project, from the engineer to the adhesive supplier, will have different reasons and motivations for potentially requiring a self-leveller and moisture barrier:

Structure specification (architect/engineer)
Changes in construction techniques, such as changes in types of surface beds and suspended slabs, have affected the way the structure is designed. While there are time, cost and environmental benefits for these structural changes, they also have an impact on the subfloors that a flooring contractor has to work with.

Building and flooring contractor (contractor/sub-contractor)
While it is the building contractor’s legal responsibility to produce a screed that is sufficiently hard, smooth and flat, this has become somewhat difficult with today’s level of skill in the building industry. It has therefore fallen to the flooring contractor to use self levelling products to ensure a Class 1 screed. Testing for moisture is the responsibility of the flooring contractor. With power floated screeds and fast tracked building, it is rare to find a screed that is sufficiently dry and does not require a moisture barrier, especially on ground floor surface beds.

Adhesive supplier
There have been changes in adhesive formulation to ensure the safety of installers and to meet stricter environmental requirements. Adhesives now have far less solvents and are more water based thus more susceptible to moisture than the high solvent adhesives were. Therefore the use of a moisture barrier is often required in order to prevent moisture rising and emulsifying the adhesive.

Flooring material supplier
Whilst the formulation of vinyl floor coverings have changed little over the last 20 years, other than removing harmful or banned substances, the fast tracked building environment and lack of skills in the industry have led to more costly sub floor preparation.

Quantity Surveyor
A quantity surveyor will be in the best position to provide a financial overview of a complete floor installation and compare past installations to present-day ones. Everything from traditional building methods and adhesives to modern methods would need to be carefully weighed to determine the total financial cost savings.

Are new subfloor methods and products a cost saving? Does fast tracked building also save costs? The question begs are vinyl floors really more expensive now or are the additional costs as a result of cost savings in other areas?

Vinyl flooring installations require a very specific preparation and installation technique. Some points every flooring contractor needs to keep in mind when preparing for a vinyl installation are the following:
• The screed will become your problem. You will ultimately be responsible for ensuring that the screed is sound, level and sufficiently dry before installing the vinyl flooring or you could jeopardise the success of the installation.
• Keep a R2 coin handy. To ensure levelness, you shouldn’t be able to insert more than a R2 coin under the straight edge at any point along a 3m length of screed.
• Check moisture. The Wagner meter or Protimeter are reputable tools that will enable you to read the moisture levels at the correct depth. Check readings in different areas because factors such as ventilation and ground conditions can have an impact on moisture readings.
• Use a self-leveller and moisture barrier. In order to mitigate any risks when installing vinyl flooring, it is always advisable to use a moisture barrier and self levelling product to ensure correct flooring preparation for a successful installation.

For more information, visit www.polyflor.co.za, email marketing@polyflor.co.za or call +27 (11) 609 3500 to speak to Blythe or Wendy.

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