These screeds are based on calcium sulfate and are growing rapidly in popularity. The PIPE2000 System Board and 15mm PEX pipe are specifically designed for use with flowing screeds.

Although the anhydrite material is more expensive than traditional sand/cement screeds, the thinner floor section and the speed of application, together with other potential benefits in programme time often makes the overall package more cost-effective.

To summarize the advantages:

• Good flow and contact around Underfloor Heating pipes.

• Generally a 55mm thick screed (i.e. giving a 40mm cover over a 15mm pipe) can be used to compared to a 65-75mm sand/cement screed. This gives a significant weight saving and allows the Underfloor Heating to respond more quickly. Note: To estimate the ammount of material (m²) required for a specific project, multiply the m² x 50/1000. The result takes into account for the volume of material displaced by pipe and castellations of the PIPE2000 System Board.

• Large areas can be poured wthout the risk of curling. Particulary suited to sports halls, atria, schools etc.

• Speed and efficiency of screeding operation. Less time on site. Areas available sooner to following trades.

• Mixed off site under strict quality control procedures. More consistent compaction and lack of voids.

• Virtually no construction joints required.

• Suitable for most applications from heavy duty to domestic.

• Surface regularity to British Standard SR2.

• Protein-free and will not encourage the growth of bacteria.

Please note that:

Areas below 250m² in one pour or sites which are located too far away from a batching plant are unlikely to be viable. Anhydrite screeds are not a wearing surface and a final floor finish must be applied. Sealers, primers or latex may be required depending on the floor finish involved.

For more information vist www.lafarge-aggregates.co.uk and find Agila Screed A under the product listing.

Or:

www.rmc.co.uk and select Readymix Supaflo

“Doing It Right” – An Article By Ian Moxom, Managing Director of PIPE2000

Combining Underfloor Heating with flowing calcium sulfate screeds offers significant benefits - but only if it is done properly.

The introduction of flowing calcium sulfate screeds in recent years has provided the opportunity for improved performance and cost effectiveness. It results in better response times, giving improved control, as well as reduced energy consumption, enhanced safety and a quicker installation. Such installations, however, require a different approach using specially designed systems installed by properly trained operatives.

Flowing screeds are applied in liquid form, with the screeds being pumped through large diameter hoses. The physical properties of the material allow a thinner screed (around 55mm overall thickness compared to 75mm for sand/cement screeds) which is also stronger and more consistent in quality. Our experience shows that under normal circumstances one team of four operatives can apply screed at rates of up to 1000m² a day – far faster than sand /cement screeds.

As the screed is applied, it flows all round the pipe, forming a void-free intimate contact that would be virtually impossible to achieve using a sand/cement screed. This intimate contact allows heat to diffuse evenly within the screed. And, because this screed is thinner, there is less material to heat so the space reaches its design temperature earlier. Similarly, when the heating is switched off, the screed cools more quickly. This means that pipes embedded in a thin, flowing screed provide quicker response and improved energy efficiency compared to traditional sand/cement screeds. These characteristics of flowing screed also impose certain requirements on the type of system used. For that reason, it's essential that the system specified has been designed for use with flowing screeds.

For example, if the work area is not sealed the screed will penetrate any gaps and the insulation boards may float up. Similarly, if the pipes are not held securely over their full length, the relatively dense flowing screed will lift the pipe between the fixing points. Even steel mesh, which is traditionally used as a clipping system for Underfloor Heating, will not be heavy enough to hold the pipes.

In order to make it easier to meet these requirements in the simplest and safest way possible, PIPE2000 offers a complete system for this type of application. It consists of insulation board, a pipe holding system and sealing - and is supplied in modular format for ease of delivery and installation.

The pipes are set into the system board, which incorporates raised pads. These hold the pipes securely and prevent them from been dislodged or damaged. It also provides a safe base for the laying engineers and screeders to walk on. Our experience of many projects has shown that the trip and injury hazards that are common with mesh clipping systems are eliminated by this base board system.

Though not suitable for all projects, calcium sulfate screeds are now frequently used for many projects over 300m². We can expect to see them used in conjunction with UFH on a regular basis.

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Underfloor Heating - Flowing Screeds
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