Thin-layer heat screed construction on partition and insulating layer

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Solution Overview

Problem

Existing heated screed constructions for buildings often require direct bonding to the substrate, leading to increased construction heights and inadequate stress absorption, particularly when modernizing residential buildings or requiring thermal or sound insulation.

Innovation Solution

A heating screed construction utilizing foil elements for heating pipes, calcium sulphate screed, and insulating or separating layers such as expanded polystyrene or coated special paper, which allows for a construction height of less than 35 mm without direct bonding, reducing tensile and bending stresses through the use of low-expansion calcium sulphate screed and stress-distributing knob elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a standard heated screed construction is used, then the heating function is provided, but the construction height becomes too large (55-65 mm) for modernization projects

Engineering Contradiction:
Improveconstruction heightVSAvoidheating function provision
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The screed is segmented into multiple thin layers (first screed layer 14, second screed layer 15) with different materials and functions. The first layer uses calcium sulphate for rapid drying and low thermal expansion, while the second layer provides structural completion, allowing the total height to be reduced to 20-35 mm while maintaining heating functionality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite material construction with calcium sulphate screed (anhydrite) combined with heating pipes and insulation layers. This composite structure achieves both the reduced height requirement and reliable heat transmission, as calcium sulphate has favorable thermal and mechanical properties for this application

Inventive Principle:
Principle #40Composite materials

2Strength

If direct bonding to substrate is required, then stress absorption is improved, but construction complexity increases and insulation requirements cannot be met

Engineering Contradiction:
Improvestress absorptionVSAvoidbonding requirement
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

An insulation layer (12) is placed beforehand between the heating screed construction and the substrate to cushion and distribute stresses. This prevents direct bonding requirements while still providing stress absorption, as the insulation layer acts as a compliant interface that accommodates thermal and mechanical stresses

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The insulation layer serves as an intermediary element between the heating screed construction and the substrate. It mediates the stress transfer, allowing the screed to be laid without direct bonding while still achieving adequate stress absorption through the insulating material's mechanical properties

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by stationary object

If insulation layer is added, then thermal and sound insulation is provided, but construction height increases

Engineering Contradiction:
Improvethermal insulationVSAvoidconstruction height
Core Design Contradiction:
Use of energy by stationary objectVSLength of stationary object

Solution Approach 1:

The invention changes the parameters of the screed material to calcium sulphate, which has low thermal expansion and high strength, allowing the screed layers to be made thinner (20-35 mm total) while maintaining structural integrity. This enables the inclusion of insulation layers without excessive height increase, as the screed itself contributes less to the total thickness

Inventive Principle:
Principle #35Parameter changes

4Strength

If thicker screed is used, then tensile force absorption is improved, but construction height and drying time increase

Engineering Contradiction:
Improvetensile force absorptionVSAvoidscreed thickness
Core Design Contradiction:
StrengthVSLength of stationary object

Solution Approach 1:

The use of calcium sulphate screed as a composite material provides both the necessary tensile strength and rapid drying properties. Calcium sulphate has inherently low thermal expansion (reducing tensile forces) and high permeability (accelerating drying), allowing thin screed layers of 20-35 mm to achieve the same tensile force absorption as much thicker conventional screeds

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables a low-profile heated screed system that can be installed without direct substrate bonding, effectively managing stress and achieving rapid drying and readiness for flooring, while maintaining insulation and sound reduction properties.

Implementation Method 1

Due to temperature expansion and frictional forces, tensile forces occur in the heated screed, which must be absorbed by the screed cross-section

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the insulating layer is selected from expanded polystyrene (EPS), soft wood fibres, mineral wool, rubber or foamed polyurethane or phenolic resin, vacuum insulating materials or insulating materials based on aerogels

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

heating pipes; where the heated screed construction without the insulating or separating layer has a construction height of less than 35 mm

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2210866B1Thin-layer heat screed construction on partition and insulating layer
Publication Date: 2021.09.15 KNAUF GIPS KG

AI summary

The structure includes: a sheet component holding heating pipes, the heating pipes themselves and a calcium sulfate- or plaster-based screed. Without insulating- or separating layers, the structure has a thickness less than 35 mm. The insulating layer is selected from expanded polystyrene (EPS), soft wood fibers, mineral wool or rubber. Further alternatives include foamed polyurethane or phenolic resin, vacuum insulation or insulation based on aero-gels. The separation layer is selected from a coated speciality paper, film, foil or thin insulation sheeting. The sheet component is adhesively-bonded to the insulation- or separation layer. The screed is ready to accept loading seven days after laying. To make the screed, 20%-50% of CaSO 4binder is used. This is added to ballast comprising limestone, quartz sand or natural anhydrite. The ballast grading is preferably between 0-0.5 mm and 0-2.5 mm. Additives are optionally included to promote flow and control setting. An independent claim IS INCLUDED FOR the corresponding method of manufacture.