SOME of the region’s most prestigious industrial and commercial developments, including Dubai International Airport, Dubai Cricket Stadium and Dubai Marina Towers have made use of Flowcrete Middle East’s innovative Isocrete Floor Screed systems to ensure that their floors can withstand the diverse and challenging on-site conditions of such large-scale environments.

Screeds provide a vital layer in a floor that bonds the finish people see and walk across every day to the concrete substrate of the building’s construction. For commercial locations, which will undergo frequent traffic, a more robust screed is required than is used in residential projects.

If properly applied and maintained, most screeds need never be seen until the building comes to the end of its life and is dismantled. However failures in the planning, application, curing or drying processes can lead to later, potentially very costly, problems.

“The screed layer may stay hidden underneath the final floor finish or protective coating, but it is a vital component to ensuring that an attractive, hardwearing and effective surface can remain operationally sound above the building’s concrete substrate throughout its projected lifecycle,” says a spokesman for Flowcrete.

He continues: “It’s important to understand the requirements of your project and the viability of the different types of screeds and methods of application. The same solution should not be copied and pasted into a different scenario, as the relevant individual factors of the project may not be the same.

“Essential factors to consider include the projects scale, budget, underfloor heating or cooling systems, environmental impact, insulation, construction schedule, durability requirements and development constraints. For example an operating theatre or workshop area will need a heavy-duty system whereas an office room will likely require a light duty screed.

“The planning process is vital to making sure the screed does not fail, as if the wrong screed is chosen, the wrong thickness applied or the wrong installation method used then a whole range of failures and problems are likely to occur.”

Traditionally screeds are sand and cement mixtures, blended and applied on site. However these are often unpredictable as the ratios and properties cannot be exactly determined and so can lead to a weak layer liable to crack, peel or collapse without warning.

Vik Vithlani, sales director for Flowcrete Middle East suggests: “Traditional sand and cement screeds have high levels of failure. Proprietary screeds that are pre-packed and pre-weighted, such as those in our Isocrete range, not only meet modern performance levels but offer enhanced features including fast-drying times and a reduced risk of cracking, giving the client peace of mind.”

The Isocrete K-Master ... automated screeding machine.

Flowcrete Middle East has produced a range of proprietary screeds with enhanced strength and a faster application speed that will react more predictably.

“Generally speaking, there are two types of screed, a semi-dry formula which is hand applied and then trowelled to a finish and a liquid, free-flowing mixture that is pumped to a prescribed depth,” the spokesman says.

“Of these types, there are several different identifiable screeds with different properties which will thrive or fail in various environments and which can be applied in varying thicknesses.

“An advantage of semi-dry screeds is that they can be laid at an angle. This is useful for applications such as floors that need to slope to a drain or internal ramps.

“Self-levelling screeds are applied in a liquid form which smoothes itself out over a given area whilst the semi-dry version has to be levelled by hand or machine. Self-levelling screeds will usually arrive as a dry powder and have water added. They are very sensitive to the ratio of water used, too much and it will segregate and crack, too little and it won’t level correctly.

“The thickness of the layer will vary depending on the screed type and the load requirements of the floor. Thicker screeds will generally take longer to install due to an increased drying time, however fast drying systems can be utilised to avoid long delays to construction programmes.”

Flowcrete Middle East’s innovative Isocrete K-Screed is an award-winning semi-dry cementitious screed which has a good reputation within the construction industry and architectural community for combining high strength and excellent moisture control with a very quick installation turn around. The K-Screed includes a plasticising and accelerating admixture called K-additive that modifies and enhances the screed performance compared to traditional screeds.

More than 300,000 sq m of Isocrete K-Screed was installed at Dubai International Airport, representing one of the largest consignments by the company to date. The material was specified across all five levels of the airport’s adjoining multi-storey car parking facility as well as underneath the ceramic tiles in the passenger arrivals hall.

The system also has an impressive international track record having been used at various landmark buildings including Soccer City Stadium in Johannesburg (South Africa); Wembley Stadium in London (UK); Chep Lap Kok Airport in Hong Kong and The Wynn Resort and Casino in Macau as well as at major shopping malls including Westfield in London, Festival City in Dubai and Médiacité Liège in Belgium.

Investment into research and development has enabled Flowcrete Middle East to introduce a range of sustainable features to its Isocrete Floor Screeds range, without any compromise on the performance of the products, which have been used on commercial developments around the world for decades.

A major development has been the removal of Ordinary Portland Cement (OPC) from the products.

Isocrete Green Screeds also contain up to 40 per cent recycled materials – most of which have been reclaimed from heavy industry and would otherwise be sent to a landfill. This includes fly ash (otherwise known as pulverised fuel ash or PFA), which is used to reduce the overall carbon dioxide (CO2) footprint of the screed and improve surface finish as well as reduce permeability and shrinkage.

Improved flexural and compressive strength also ensure Isocrete Green Screeds can remain in-situ for the lifetime of a building, minimising the cost and impact of repairs.