Underfloor heating filler LL 5500

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Product description

The Fescon Underfloor heating filler LL 5500 is a fibre-reinforced, casein-free underfloor heating filler compound with a special cement binder that hardens and dries rapidly. 

  • For layer thicknesses 10-80 mm
  • Manually levelled


  • Underfloor heating filler for indoor concrete floors
  • Underfloor heating filler for indoor primed plasterboard floors
  • Graded floors requiring rapid hardening and drying
  • Ceramic or stone tiles, or parquet, for example, can be installed on the levelled base
  • If necessary, finish with Fescon FlowPlan. Fine levelling is recommended when installing plastic or textile carpets, vinyl tiles or cork
  • Overlaid underfloor heating filler LL5500 can be waterproofed according to the Fescon waterproofing instructions
The product is listed in the portal for building products that can be used in Nordic Swan Ecolabelled buildings.
GTIN code Product name Product number Package size
6416841202017 UNDERFLOOR HEATING FILLER LL 5500 20 KG 20201 20 kg



  • Clean, solid and dust-free
  • Sufficient strength, load-bearing capacity and immobility
  • Temperature >+10oC and relative humidity <95% RH
  • Any substances reducing or preventing adhesion must be carefully removed


  • Carry out the priming in accordance with Fescon Adhesive Primer instructions
  • When beginning the levelling work, there must be no puddles of primer

Instructions for use

  • Mix a bag of the levelling compound in 3.0-3.6 litres of clean water
  • Mix the LL 5500 into a consistent paste using a drill paddle
  • Spread the compound on the base and level with a steel trowel
  • Working time is around 20 minutes from adding the water
  • Wash the tools and equipment with water immediately after completing the work
  • Remove dried levelling compound mechanically


  • The Fescon LL 5500 can be covered with all flooring materials, including natural materials
  • We do not recommend leaving the floor levelling compound without coating

Storage and handling of waste
See the separate storage and disposal instructions https://www.fescon.fi/en/material-bank

Material usage

1.8 kg/m2/1 mm

Water requirement 3.0-3.6 l/20 kg
Binder special cement
Aggregate lime filler
Colour gray
Maximum grain size

1.2 mm

Package size 20 kg

12 months in a dry room

Mixing time 1-2 min
Layer thickness

10-80 mm

Fibre plastic fibre
Usage temperature


Workability time approx. 20 min
Drying time

1 mm/h (+20°C, 50% RH)

Walkable approx. 2- 3 h
Strength class C 20 (EN 13813)
Compressive strength

> 30 MPa (28 days, +20°C, RH 50%)

Adhesion strength

28 days > 1.2 MPa

Flexural bond strength F 5 (EN 13813)
Surface tensile strength > 1,0 MPa (28 days, +20°C, RH 50 %)


Limitation of liability, product use notes and restrictions: Please familiarize yourself with Fescon Oy's general terms of delivery and the design and work instructions related to the product.