On the safe side in terms of building physics

Nothing to stand in the way of the planning process

Clay has outstanding building physics properties, which is why it has therefore been considered a healthy and ecologically particularly valuable building material for thousands of years. We have optimised it for today's world. If you prefer a modern lightweight construction, consistently sustainable and environmentally compatible buildings, and if you want to enjoy complete and utter planning freedom, then Lemix® is a first-class alternative. Lemix® clay boards are dry and used in the same way as gypsum plasterboards for all purposes of interior finishing construction. They also have excellent properties for indoor climate and acoustics.

Lemix® preserves wood

Clay has a very low equilibrium moisture content. This has a positive effect on adjacent materials: When wood and other organic materials are surrounded by clay, they are dehumidified and kept dry. Fungi and insects don't stand a chance to get a foothold in them. Which can be seen in centuries-old half-timbered houses.

Warm in winter, cool in summer

Clay belongs to the group of heavy building materials and is therefore a good heat accumulator. It is particularly useful for drywall construction, because traditionally, construction there is an uphill battle as the lightweight construction only has a small storage mass. Using Lemix® with its very high heat storage capacity for such scenarios, you can create an incomparable room climate and help to ideally regulate humidity. Similar to a solid brick, clay absorbs the heat evenly and slowly releases it again. Consequently, Lemix® stores heat in winter and protects from overheating in summer.

Comparison of a lightweight clay board or plasterboard with Lemix® clay boards.

The specific heat capacity of a material indicates how much energy (heat or cold) must be added/removed from a material in order to heat/cool 1 kg of this material by 1 Kelvin (1 degree Celsius). Together with water vapour adsorption, the specific heat capacity of building materials is largely responsible for a pleasant indoor climate. Particularly with clay boards, high density and the associated high weight per square metre provide the typical "comfortable ambient climate".
Examples for the storage capability:

Spezifische Wärmekapazität c
Flächenbezogene Speicherenergie
Lemix® Lehmplatte 1450 1100 ¹ 22 32 35,2
16 23 25,3
Leichtlehmplatte 700 1450 ¹ 22 15 21,8
14 10 14,5
Gipsbauplatte GKB 680 960 ² 12,5 8,5 8,2
¹ nach Lehmbauregeln ² nach Gipsdatenbuch

The examples showed that a Lemix® clay board has 60 % more storage capacity of light-weight clay panels with the same wall thickness.

Brief technical information
Panel size 62,5 × 125,0 cm
Panel thickness / m² 16 mm 22 mm
Panel weight approx. 18 kg approx. 25 kg
Panel weight / m² approx. 23 kg approx. 32 kg
Pallet loading 60 pieces = 46,9 m² 40 pieces = 31,2 m²
Item number 17 000 2016 17 000 2022
Bulk density approx. 1.450 kg/m³
Sound insulation value up to 56 dB with a 15 cm thick clay partition wall
Thermal conductivity λ = 0,353 W/mK
Building material class A1 (non-flammable) according to EN 13501-1:2010-01
Vapour diffusion resistance μ = 5/10
Cutting to size of the Lemix® clay panels with circular saw is recommended.
Lemix® clay panels can be used on all conventional substructures used in drywall construction.
Lemix® clay panels can be glued, clamped or screwed onto solid, full-surface substrates.
Lemix® clay panels comply with DIN 18948 of December 2018.
Structure of a Lemix® partition wall
Aufbau einer Lemix® Trennwand

Sound, water, strength - top-class values

Lemix® provides particularly good sound insulation

Sound insulation primarily correlates with mass, which is why clay is the ideal building material for good sound insulation values due to its high bulk density.
With clay panels, the clay content of the panels is important. The Lemix® clay panels have a bulk density of 1.450 kg/m³.

For comparison:
A plastered brick wall with a total thickness of 14.5 cm and a raw density of 1,0 kg/dm³ achieves a sound insulation value of 45 dB..

Sound insulation values for partition walls made of Lemix® according to DIN EN ISO 10140-2

Sound insulation test arrangement 1:
Wooden wallboard construction 60 × 80 mm
with jute insulation of 80 mm
planked with Lemix® 22 mm and plastered on both sides
total wall thickness approx. 13 cm
sound insulation value 52 dB

Sound insulation test arrangement 2:
Wooden wallboard construction 60 × 80 mm
with jute insulation of 80 mm
planked two layers Lemix® 22 mm and plastered on both sides
total wall thickness approx. 15 cm
sound insulation value 56 dB

For partition walls in residential buildings, the requirement is 53 dB, for example.

Lemix® schirmt Schall besonders gut ab
Lemix® complies with DIN 18948

Standards create a uniform compliance basis and verifiable evidence. This gives security to both planners and processors. The new DIN 18948 of December 2018 defines the requirements, testing and marking of clay panels. It also defines the acceptable components of clay panels. Lemix® complies with DIN 18948 and provides the security of being a "real" clay panel.

By the way: DIN 18948 was developed in cooperation with the experts from Lemix. Part of the standard is also: The previous product name “clay building slabs” has now been changed to “clay boards”.

Water vapour adsorption in the highest category WSIII

One measure of the moisture-regulating properties of clay panels is water vapour adsorption, i.e. the ability to absorb a certain amount of moisture in a certain period of time. Clay panels complying with DIN 18948 must absorb at least 7.0 g/m² per hour. Lemix® clay panels are capable of absorbing more than 13 g/m² during this time and can therefore be included in the higher water vapour adsorption class WSIII.

Tested and found to be superior

The water vapour adsorption properties of the Lemix® clay boards were tested in detail under various conditions. The results show how much better the Lemix® boards perform.

Lemix® is stable

The mechanical properties of clay panels are regulated in the new DIN 18948. The surface tensile strength is important here in order to provide sufficient support for a coating with clay plaster, for example. According to the standard, the adhesive strength of the surface should be at least 0,1 N/mm². Lemix® clay panels have more than twice the surface tensile strength and thus guarantee safe coating.

Lemix® also meets and exceeds the requirements for surface hardness. When measuring the surface hardness, a 50 mm steel ball is dropped onto the clay panel and the resulting indentation is measured. If it is smaller than 15 mm, the panel may be classified as a clay panel with increased surface hardness. It goes without saying that Lemix® panels provide increased surface hardness.


Lemix® is not flammable!

The fire behaviour of Lemix® clay panels was tested in accordance with DIN EN 13823. According to DIN EN 13501-1 the highest classification A1 was achieved.

Fire protection test arrangement 1:
Wooden wallboard construction 60 × 60 m
with jute insulation of 60 mm
planked with Lemix® 22 mm on both sides total
wall thickness approx. 11 cm
fire resistance duration EI45 (=F30)

Fire protection test arrangement 2:
Wooden wallboard construction 60 × 80 m
with jute insulation of 80 mm
planked with Lemix® 22 mm on both sides total
wall thickness approx. 13 cm
fire resistance duration EI90 (=F90)

Fire protection test arrangement 3:
Wooden wallboard construction 60 × 80 mm
with jute insulation of 80 mm
planked with double layers of Lemix® 16 mm on both sides total
wall thickness approx. 15 cm
fire resistance duration EI120 (=F120)

In addition, it was proved that double-layered planking of walls with Lemix® 16 mm has achieved a fire resistance duration of 30 min (F30).

It can't be hot enough for our clay plates.
In fire resistance tests, a wooden wallboard construction with Lemix® achieved a fire-resistance of 120 minutes.

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