Exterior Façades with Natural Stone Cladding

The aim is to reliably assess moisture penetration, water absorption, and drying behavior in plaster, masonry, concrete, natural stone, and coatings.
In practice, indicative in-situ measurements are combined with standardized reference/laboratory methods. DIN 4108-3 applies to building physics assessments in Germany.

How is it tested? (typical procedure)
Orientation measurements (e.g., electrical/capacitive) for mapping damp zones. In situ detection of water absorption with test tube (Karsten principle) according to DIN EN 16302 – suitable for porous, inorganic building materials.

Laboratory/reference:
Moisture content determined by drying (kiln drying method) in accordance with DIN EN ISO 12570;
depending on the issue at hand, additional capillary water absorption coefficient in accordance with DIN EN ISO 15148 and – for coatings – water vapor permeability in accordance with DIN EN ISO 7783. The results are included in the verification in accordance with DIN 4108-3.

Relevant standards (selection)

• DIN EN 16302 – Measurement of water absorption at low pressure (in situ/laboratory).
• DIN EN ISO 12570 – Determination of moisture content by drying.
• DIN EN ISO 15148 – Determination of the capillary water absorption coefficient.
• DIN EN ISO 7783 – Water vapor permeability (cup method) of coatings.
• DIN 4108-3 – Climate-related moisture protection: requirements, calculation, evaluation.

The peel test assesses the adhesion of elastic adhesives/sealants (e.g., for facade joints) to concrete substrates. DIN ISO 21194 is the current standard (replaces DIN 54457).

How is the test performed?
A defined bead of sealant is applied to the prepared substrate, allowed to cure, and then peeled off under specified conditions.
The type of failure/fracture patterns (adhesive, cohesive, mixed) and, if required, the peel force are evaluated. Optional pre-aging in accordance with the standard can be agreed upon.

Special features of facade joints
DIN 18540 (planning, execution, product requirements) applies to exterior wall joints in building construction. Joint sealants used must comply with EN 15651-1 (CE marking for facades). The bead peel test is the practical proof of adhesion/suitability on the specific substrate.

Relevant standards (selection)

• DIN ISO 21194 – Bead peel test for elastic adhesives/sealants.
• DIN EN ISO 10365 – Designations of fracture patterns of adhesives.
• DIN EN ISO 9142 – Guidelines for laboratory aging conditions.
• DIN 18540 – Sealing of exterior wall joints in building construction.
• EN 15651-1 – Joint sealants for facade elements (CE marking).

The cross-cut test is a quick orientation test for the adhesion of coatings to the substrate. It provides a visual classification in classes 0–5 (0 = very good) and no adhesive strength in N/mm².

How is it tested?
A cross-cut tester is used to make intersecting cuts down to the substrate (cut spacing appropriate to the layer thickness). Loose particles are removed and, if necessary, adhesive tape is briefly applied and pulled off. The tear pattern is classified into classes 0–5 according to the standard.

Important for classification
For thick/multi-layer systems, especially corrosion protection on steel: Cross-cut/X-cut according to ISO 16276-2 (usually published in Germany as DIN EN ISO 16276-2).
For numerical adhesion strength: Pull-off test according to DIN EN ISO 4624.

Relevant standards (selection)

• DIN EN ISO 2409 – Cross-cut test.
• ISO 16276-2 / DIN EN ISO 16276-2 – Evaluation of adhesion (cross-cut/X-cut) for protective coatings.
• DIN EN ISO 4624 – Tear-off test (adhesion strength in N/mm²).

No, we do not sell a complete ETICS package. You can buy the natural stone veneers from us, which you can bond to the mineral substrate reinforced with reinforcing mesh as the final top layer.

The basic structure of the ETICS façade is carried out in accordance with current regulations and standards.
The reinforcing mesh must be located in the upper third of the render layer (executed in accordance with VOB/C[1]ATV-DIN 18350, DIN EN 13914 and DIN 18550), whereby the thickness of the render layer must not be less than 5 mm.
Unevenness must not exceed ± 3 mm so that the adhesive application using a B3 notched trowel provides sufficient adhesion.

You don't have to build a completely new façade to upgrade it with Slate-Lite stone veneers.
As long as the existing façade is in good general condition and structural integrity, existing façades can also be extended without any problems!

The integrity of your existing façade can be checked by an expert using simple cross-cut tests, bead peel tests and moisture measurements.

• The substrate must be dry, clean, frost-free, solid and free from microbial infestation.
• Low-strength or non-load-bearing surface layers, separating layers (e.g. dirt, dust, grease, oil, paint residues, etc.) must be removed.
• Previously applied undercoat plasters, fillers and similar must be completely dry/hardened and have sufficient load-bearing capacity.

No, joints are not required if the covering area does not exceed 8 m in length or height.
If the processed area is larger, an expansion joint is recommended.

Almost all Slate-Lite decors are suitable for outdoor use and as a stone façade.
Exceptions to this are our ICE PEARL and GREEN PEARL limestone decors, which are not approved for outdoor and wet areas.

Our sales department will be happy to send you a list of all the decors that you can use for your natural stone façade. Just get in touch with us!

Slate-Lite can generally be laid butt-to-butt so that you simply push the stone slabs together.
If you would prefer to use finishing profile strips (especially for the outer edges of the building), we have finishing strips in several colors in our portfolio that perfectly match the overall thickness of Slate-Lite.
As the natural stone surface of Slate-Lite is rough and therefore there are slight differences in height due to the stone structures and grains, we recommend the use of profile strips in the façade area.

The Slate-Lite cladding is not open to vapor diffusion due to the GRP support of the stone material.
This means that no moisture can penetrate.

Thanks to the 100% natural stone surface, you generally do not need to protect Slate-Lite stone veneers for outdoor use with an impregnation or sealant.

If you require additional protection against snow, salt or rain in addition to the natural properties of the stone surface, we recommend the use of our Slate-Lite Special Protection for outdoor use.

We provide a 5-year guarantee in accordance with German law, provided that all façade work is carried out correctly and in compliance with the applicable standards and specifications.
However, our long-term tests and experience with façade projects show that you will enjoy your new stone façade for 20 years or more.

Thanks to the 100% natural stone surface, the weathering of our stone veneers causes hardly any or minimal uniform deviations in color.

Signs of weathering such as black mold, algae, green deposits or other environmental soiling can usually be removed quickly and easily with clear water and a brush.
In outdoor areas, cleaning with a high-pressure cleaner is also possible, but please observe the distance recommended by the appliance manufacturer when using it.