Schlüter-BEKOTEC-EN-FTS  Low-noise studded screed panel

The reliable Schlüter-BEKOTEC-EN 18 FTS covering assembly technology is a system for crack-free and functionally safe floating screeds and heated screeds, with coverings made of ceramics, natural stone and other covering materials.

This floating system is installed directly on load-bearing, weight-distributing substrates, such as concrete, as well on existing wooden ceiling structures or bound fills (> 100 kPa). Similarly, the use of additional thermal insulation materials is permitted. The suitability of the substrate for heating purposes must be verified (movement joints, edge strips, etc.). The system is based on the Schlüter-BEKOTEC-EN 18 FTS studded screed panel with integrated sound insulation of 5 mm, which is installed directly on the load-bearing substrate. An impact sound improvement of 25 dB in accordance with DIN EN ISO 717-2 has been measured for the system. The actual improvement offered by the respective assembly depends on local conditions (structural design) and may differ from this measured value. The measured test values do not, therefore, always apply for the situation at the respective construction site. Accurate values can only be determined by direct measurements on site, while taking into account the actual structural design. The geometry of the BEKOTEC-EN 18 FTS studded panel dictates a minimum screed layer thickness. The thickness is 26 mm between – and 8 mm above – the studs. The stud distances make it possible to clamp the corresponding heating pipes (with a diameter of 12 mm) in a 50 mm grid to produce a heated screed.

The floor heating system is easily adjustable and is ideally suited for operation at low supply temperatures. That is because just a relatively small amount of screed has to be heated or cooled (with a coverage of 8 mm, approx. 52 kg/m² ≙ 26 l/m²).

As the screed hardens, some shrinkage occurs. This is configured in a modular studded pattern. Stresses resulting from contraction buckling do not, therefore, affect the entire area, and it is not necessary to install movement joints in the screed. Once the cement screed is ready to support weight, the Schlüter-DITRA uncoupling mat (alternatively, Schlüter-DITRA-DRAIN 4 or Schlüter-DITRA-HEAT) can be installed (gypsum-based screed ≤ 2 CM %).

Ceramic tiles or natural stone can then be installed directly over this layer, using the thin-bed method. Movement joints can be created in the covering layer with Schlüter-DILEX according to industry standards.

Covering materials that are not susceptible to cracking (such as parquet or carpeting), are installed directly over the screed as soon as it reaches the corresponding residual moisture level.

Further information can be found in our Technical Manual.

Technical data

1. Stud size: approx. 40 mm
   Installation spacing: 50, 100, 150 mm ...
   Matching heating pipes: ø 12 mm
   The studs have a cutback design to securely keep heating pipes in place without the need for clamps.
2. Connections:
   The studded panels are connected by overlapping a row of studs and interlocking the panels together.
3. Working area: 1.4 x 0.8 m = 1.12 m²
   Panel height: 23 mm (incl. 5 mm sound insulation)
4. Packaging: 10 units/box = 11.2 m²
   Box dimensions are approx. 1500 x 855 x 185 mm.

• Warranty:
  Schlüter-Systems offers a five-year warranty for the life of the covering assembly, provided all installation instructions were observed and the covering is used as intended.
• Crack-free covering:
  The BEKOTEC system is designed to reduce shearing tensions of the screed within the grid of the studded panel. No construction reinforcement is required.
• Low-buckling construction:
  The covering assembly of the BEKOTEC system is free of inherent stresses. Consequently, no buckling can occur in the area. This applies in particular to stresses resulting from temperature fluctuations, e.g. in heated screeds.
• Joint-free screed:
  No expansion joints are needed in the screed since the BEKOTEC system evenly distributes any shearing tension in the screed across the entire area.
• Movement joint in the joint pattern of the tile or paver covering:
  The BEKOTEC system allows for aligning the design of movement joints to the selected joint pattern of the covering for tile or paver coverings since expansion joints from the screed do not have to be continued into the top covering. The applicable regulations for the placement and construction of movement joints in and around the tile field must be observed.
• Short construction time:
  The uncoupling mat ensures that the screed created with the BEKOTEC system is ready for covering with ceramic tiles, natural stone or agglomerate stone as soon as the screed is ready to bear weight. Ceramic thermal comfort floors are ready for heating only seven days after the completion of the cover assembly.
• Low material requirements:
  With a screed coverage of 8 mm, only approx. 52 kg/m² ≙ 26 l/m² screed volume is needed. This advantage is also reflected in the static calculations.
• Fast responding floor heating system:
  A covering assembly using the BEKOTEC system in conjunction with a floor heating system is able to respond to temperature changes faster than a conventional heated screed since the volume to be heated or cooled is significantly smaller. This allows for operating the floor heating system in the low temperature range to save energy.

1. Install Schlüter-BEKOTEC-EN 18 FTS on a sufficiently weight-bearing substrate. The substrates must be flat and have no point-like protrusions (e.g. mortar residue). Uneven sections in the floor must be corrected with screeds or suitable bound fill in advance. If required, additional suitable pressure-resistant heat insulation (DEO) must be installed over the substrate. The applicable heat insulation requirements must be observed. Additional impact sound insulation is not permitted.
2. Cover the edges of the covering at walls or structural elements with BEKOTEC-BRS edging strips according to the screed type or height. The adhesive leg integrated in the edging strip features a self-adhesive strip on both sides for attachment. The edging strip is pressed toward the wall by the backing adhesion on the substrate and the pre-tensioning of the integrated foil leg. When the BEKOTEC studded panel is placed on top of the adhesive leg, the panel bonds with the substrate and flowing screed can no longer flow underneath the panel.
3. The BEKOTEC-EN 18 FTS studded panels must be precisely cut to size in the edge areas to avoid sound bridges. Snap the studded panels into the tapered connection studs at the edges to connect them (see picture).
   
   In door threshold areas and near distributor boxes, the smooth levelling panel Schlüter-BEKOTEC-EN 18 FGTS 5 may be used to simplify the pipe installation. This is installed below the studded panels and fixed in place with double-sided adhesive strips. It may be necessary to remove the sound insulation of the studded panel in transition areas to achieve a precise fit. The Schlüter-BEKOTEC-ZRKL 10/12 self-adhesive pipe clamping strip enables precise pipe layout in these areas.
4. Clamp the matching heating pipes between the cutback studs to create a Schlüter-BEKOTEC-THERM floor heating system. The spacing of the pipes must be selected so that it corresponds to the required heating output, as shown in the BEKOTEC heating diagrams.
5. When installing the screed, fresh cement or gypsum-based screed is installed with a minimum screed cover of 8 mm over the studded panels. A compressive strength of C20 to C35, as well as a flexural tensile strength of F4, max. F5, must be maintained for both cement and gypsum-based screeds. If the cement screed has a shrinkage class of SW1, the use of products with a higher flexural tensile strength is also possible. The layer thickness can be partially increased to max. 20 mm for levelling. Suitable flowing screeds CAF/CTF with the corresponding specifications may be used as well. The systems approved for this application must be taken into account here.
   
   Note: Please contact our Technical Department in advance to discuss different screed properties for specific projects.
   
   To prevent impact sound transmission between two rooms, separate the screed in the relevant places with the Schlüter-DILEX-DFP expansion joint profile.
6. The DITRA uncoupling mat (or, alternatively, DITRA-DRAIN 4 or DITRA-HEAT) is bonded in place in accordance with the installation instructions provided in the product data sheets as soon as the screed is ready to bear weight. The uncoupling mat can be installed over gypsum-based screeds as soon as they have reached a residual moisture level of 2 CM % or less.
7. Ceramic tile or natural stone coverings can then be installed directly on top of the uncoupling mat, using the thin-bed method. Divide the covering above the uncoupling mat into fields, using movement joints – in accordance with the applicable regulations. Schlüter-DILEX-BWB, Schlüter-DILEX-BWS, Schlüter-DILEX-KS, Schlüter-DILEX-AKWS or Schlüter-DILEX-F profiles can be used for creating movement joints (see product data sheets 4.6–4.8, 4.18 and 4.23). Install the Schlüter-DILEX-EK or Schlüter-DILEX-RF corner movement profile as a flexible edge joint in the area of the floor-wall transition (see product data sheet 4.14). Cut off the protruding part of the BEKOTEC-BRS 808 KSF edging strip in advance.
8. When using BEKOTEC-THERM ceramic thermal comfort floor as a floor heating system, the full covering assembly is ready for heating just 7 days after completion. Start from a water temperature of 25 degrees C and increase the supply temperature by no more than 5 degrees C a day until the desired usage temperature has been reached.
9. Covering materials that are not susceptible to cracking (e.g. parquet, carpet or vinyl coverings) can be installed without the uncoupling mat, directly on top of the BEKOTEC screed. Please adjust the screed thickness to the relevant material thicknesses.
   
   Note: In addition to the applicable installation guidelines, please observe the permissible residual moisture level of the screed for the selected covering material. For detailed installation instructions in conjunction with non-ceramic surface coverings, please refer to our technical manual for Schlüter-BEKOTEC-THERM or contact our Technical Department.

Schlüter-BEKOTEC-EN 18 FTS with 5 mm sound insulation is made of impact-resistant structured polystyrene. The sound insulation fleece is made from a special textile blend. Schlüter-BEKOTEC-EN 18 FTS is suitable for conventionally applied cement or gypsum screeds as well as flowing screed.