Gypsol HTC

Our Gypsol HTC is a high strength high-performance screed explicitly designed to enhance the thermal properties of an underfloor heating system.

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Alan Jackson

Alan Jackson

National Commercial Manager Gypsol - UK & Ireland

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Gypsol HTC; a high-performance screed designed explicitly for underfloor heating

You can use this free-flowing and self-compacting screed to produce a highly efficient heating system with a co-efficient of performance some 25% higher than competing sand cement screed systems. We have our screed independently third-party verified for the thermal conductivity, which is of up to 2.5W/mK.

Our screed will give you a surface finish which is:

  • smooth
  • flat
  • level

Therefore, it forms the perfect subfloor for tiles, vinyl, laminate or any other floor covering for internal floors.

Specially trained screeders using specialised equipment pump Gypsol HTC into place. You can lay this screed thinner than other flowing screeds because it requires just 20mm cover to any underfloor heating pipes/cables. Because you are reducing the mass of screed that you need to heat, it improves overall diffusivity and offers unrivalled thermal performance.

Screed solutions for every project

We have manufactured a screed for every construction challenge. You can read all about the different Gypsol solutions from the individual product pages.

  1. Rapide; A self-compacting, self-smoothing, fast-drying floor screed
  2. Classic; Our general-purpose screeding system. The most commonly used material in our range.
  3. TS-15; An ultra-thin screed for bonded and un-bonded applications at a minimum depth of 15mm.
  4. TS-20; A thin screed suitable for bonded and un-bonded applications down to a 20mm minimum depth.
  5. XS; Extra strength material for use in heavy-duty applications, where loading is likely to be higher than normal.
  6. TimBRE; Specially formulated and tested for use in timber frame and over timber supported floors including acoustic conditions.
  7. Sureflo; Pre-blended product supplied in 25kg bags for mixing on site. Ideal where minimal quantities are required, or access for ready-mix lorries is not possible.
  8. Summit; Particularly fit for screeds pumped over very long distances or high buildings of 10 stories and above.
  9. Modular; Designed for use in modular construction to allow early movement of units, also for a lightweight steel frame and Lewis Decking.
  10. Rustique; a unique fast track floor, providing a rustic or architectural finish.
  11. Diamond; a unique and innovative “micro concrete” providing a polished floor.
Gypsol screed on underfloor heating

Gypsol HTC product details

We manufacture our Gypsol HTC to exacting standards in quality-assured Readymix facilities throughout the UK. Additionally, it is also available in specific locations from volumetric on-site mixing systems.

Because we produce this product from high-quality Gypsol anhydrite binder, specially selected sands and clean water, it offers the user a simple and effective floor screeding solution. This reasoning is especially valid for floating, unbonded or fully bonded applications which contain underfloor heating and where you need a subsequent floor covering.

Your screed benefits

Using Gypsol HTC will benefit your screed floor because of:

  • Rapid application
  • Unrivalled thermal performance
    • Up to 2.5W/mK thermal conductivity
    • Up to 25% improvement in COP
    • Reduced depth
    • Reduced operating energy
    • Higher output
    • Up to 94% lower Carbon Emissions
  • Thin Screed sections
    • 40mm Floating Commercial
    • 35mm Floating Domestic
    • 30mm Unbonded
    • 25mm Bonded
    • 20mm cover to underfloor heating pipes/cables
  • Fast drying
    • 28 days natural drying*
    • 13 days forced drying*
    • Is also available in Rapide format for even quicker drying times
  • Rapid commissioning of underfloor heating
    • Underfloor heating can be commissioned and run after just seven days
  • No reinforcement nor fibres required
  • No curing agents required
  • Low Carbon Footprint
    • Gypsol Binder produces just 26.26kg per tonne of material manufactured saving up to 94% CO2 compared to cement-based screed.
  • Fully self-compacting and high density
    • Offers 80kg/m2 density at just 40mm
  • Rapid return to service of work areas
    • Foot traffic after only 48 hours
    • Full loading after just seven days
  • Assured high strength
    • Minimum Ca-C30 – F5

*Independently tested and based on 50mm depth at 20˚C and 60% RH. We have the full test data available on request.


LKAB Minerals Gypsol HTC screed is available from all Readymix and volumetric screed producers who stock Gypsol Binder.

Gypsol HTC - Frequently Asked Questions

  • What is the minimum Gypsol HTC screed thickness my floor needs?


    You can use Gypsol HTC screed either with or without insulation to the following minimum depths

    • 40mm Floating Commercial
    • 35mm Floating Domestic
    • 30mm Unbonded
    • 25mm Bonded
    • 25mm cover to underfloor heating pipes
  • How soon can I lay my floor coverings over the HTC screed?


    At a depth of 50mm, Gypsol HTC screed dries naturally in around 28 days in the right drying conditions. If you have underfloor heating, you can commission and run this to force dry the screed in which case it will be dry in just 13 days. Gypsol HTC screed dries by evaporation of residual moisture into the air above it. It is therefore vital to ensure that you carry out drying in well-ventilated conditions to remove the moisture as it evaporates. Besides, it is also essential to ensure that you carry out an appropriate moisture test to confirm the screed is suitably dried before you apply floor coverings.

  • How will Gypsol HTC affect my underfloor heating?


    We have designed the HTC specifically for a floor with embedded underfloor heating. The type of underfloor heat can be either electric or warm water. Because you can lay it even thinner than our other screed allowing just 20mm cover to underfloor heating pipes there is less mass to heat up, allowing the screed to generate thermal inertia very quickly. Also, it has a high thermal conductivity, which has been independently tested and verified, and therefore it will produce thermal inertia at much lower operating temperatures. As a result, this product offers an unrivalled response profile making your underfloor heating up to 25% more efficient than other screed systems.