Natural stone is an excellent material for cladding a building exterior, offering weather resistance and non-combustible properties while creating an attractive appearance to any property’s façade. At SSQ, with over forty years of expertise in natural stone products, we recommend our premium Riverstone phyllite for professional cladding installations.
The importance of good preparation
SSQ’s Premium Natural Stone Cladding Products
Riverstone Phyllite – SSQ’s Sensational Architectural Stone
Riverstone is SSQ’s exceptional architectural stone product – not slate, but phyllite, made harder, denser and stronger by millions more years spent underground. This remarkable material features a distinctive satin phyllitic sheen appearance, coarse grain and naturally riven surface.
Riverstone phyllite has been selected for prestigious stone cladding projects worldwide, including the Topography of Terror Museum in Berlin, The Four Seasons hotel in New York, the Hilton in Helsinki, the Grand Lisboa Casino in Macau, and hundreds of luxury homes around the world.
The material’s exceptional weather resistance makes it ideal for cladding applications, repelling heavy rain and acting as a barrier against strong winds while shielding the building’s exterior from damage. Riverstone phyllite is also non-combustible, ensuring it will never create a fire risk.
Essential Tools and Materials for SSQ Stone Installation
Based on SSQ’s official installation guidance, professional installation requires specific tools :
Required Tools:
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Castellated trowel for adhesive application
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Spirit level for precise alignment
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Tape measure for accurate positioning
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Stone/slate adhesive (SSQ has tested Ardex X7G with E90 external additive)
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SSQ Riverstone phyllite
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Mitred corner pieces for professional finishing
Safety Equipment:
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Eye protection, face dust mask and gloves should be worn during installation
Pre-Installation Requirements
Substrate Preparation
Good preparation is key to the success of any natural stone installation. External walls to be cladded should be constructed using concrete blocks and built on top of strong concrete foundations. Walls must be flat and free of any protruding mortar.
If possible, design the wall to dimensions that minimise the number of cuts to be made to the cladding. Uneven walls will make installation of Riverstone cladding difficult and will result in an uneven surface finish.
Measuring External Walls
Before fitting SSQ stone cladding to walls, measure the length and width of your exterior to determine the right amount of material. Take extra measurements of space around windows and doors for corner pieces.
Alternatively, send scaled architectural elevation drawings to info@ssq.co.uk and we will provide an estimate.
Height Limitations and Fixing Requirements
Adhesive Installation: Riverstone phyllite can be installed up to a maximum height of 5.5m using adhesive.
Mechanical Fixing Requirements:
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100mm width stones: Maximum 0.05m² per piece, mechanical fixing required above 5.5m
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150mm width stones: Maximum 0.075m² per piece, mechanical fixing required above 5.5m
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200mm width stones: Maximum 0.1m² per piece, mechanical fixing required above 5.5m
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250mm width stones: Maximum 0.125m² per piece, mechanical fixing required above 3.0m
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300mm width stones: Maximum 0.15m² per piece, mechanical fixing required above 3.0m
Fixing the cladding to the wall
SSQ Cladding Installation Process
Preparation Steps
Prior to fixing the first course of cladding, fix a level timber batten across the length of the wall. The top of the timber batten should be set at the same height as the underside of the first course of cladding. This prevents vertical migration of the cladding before the adhesive has set.
Adhesive Application Method
Cladding should be fixed to the wall using a flexible, setting exterior adhesive. Using a tiling trowel, evenly butter the surface of the wall and the back of the cladding stone with adhesive. Firmly press the stone to the wall and check that the cladding is horizontally level using a spirit level. Using a trowel, scrape off any excess adhesive.
Corner Installation
Ensure mitred corner slates line up at both the external and internal corners, including at the recess around windows and doors. Install the remainder of the cladding as described previously.
Level Maintenance
Regularly check the levels of the cladding using a spirit level. Small plastic packers may sometimes be required to maintain an even level of cladding across the courses.
Managing Adhesive Spills
Adhesive spills are a common occurrence when installing natural stone cladding. Always keep a bucket of clean water and a cloth close to hand and remove any spills immediately.
Cutting Techniques
Should there be a need to cut to size, this operation should be carried out using a wet bed, diamond bladed table saw. Avoid cutting with an abrasive disc cutter as this will cause dry dust.
Understanding Natural Stone Characteristics
Natural stone can contain small chips which is an unavoidable part of the production process. While SSQ takes as much care as possible with handling, packaging, and quality control, some pieces may contain small chips. Most chips will be virtually undetectable once the stone is installed and will not detract from the appearance of the finished project.
During the sorting process, cladding with chips should be set aside wherever possible to be used for cuts or in less visible areas.
Fire Safety and Compliance
Following the devastating Grenfell tragedy, fire safety regulations for all types of cladding have become stricter, particularly for materials used on buildings over 18 metres in height.
Natural stone including SSQ’s Riverstone phyllite is exempt from fire testing requirements because natural slate has been repeatedly tested and proven to be 100% non-combustible for many years. Riverstone phyllite is classified as a non-combustible covering.
Technical Specifications
Thermal Performance: The U-value of natural slate has been calculated to 1.49.
Adhesive Recommendations: SSQ has tested Ardex X7G with E90 external additive.
Maintenance and Long-term Care
SSQ’s natural stone cladding requires minimal maintenance when professionally installed. Riverstone phyllite can last for well over 100 years, often outliving the building on which it is installed.
Cleaning Guidelines
When cleaning cladding stone, use a hose instead of a high-pressure washer. High-pressure washers may damage the layer of mica on the slate, altering the appearance and detracting from its natural beauty. High pressure washing can also potentially damage the joins between slates.
For moss removal or deeply ingrained dirt, use a cleaning agent suitable for natural slate – a domestic detergent should be sufficient. When scrubbing natural slate, avoid using wire brushes as residue from the metal may adhere to the slates and cause rust stains to develop.
Long-term Performance
Riverstone phyllitecomes with SSQ’s guarantee up to 100 years depending on the grade. During this extended lifespan, some repair work may be needed but this should be minimal.
Professional Installation Recommendation
We strongly recommends professional installation to ensure optimal results and maintain warranty coverage. The combination of specialized knowledge, proper tools, and quality control experience maximizes the performance and appearance of these premium natural stone products.
Applications Beyond Cladding
Due to Riverstone’s satin phyllitic sheen appearance, coarse grain and naturally riven surface that makes it more slip-resistant than natural slate, this versatile phyllite is perfect for multiple applications including flooring, stairs, skirting, patios, worktops and even swimming pools.
Project Support and Technical Assistance
SSQ provides comprehensive support throughout your cladding project. Over forty years of expertise in natural stone products ensures technical guidance from initial specification through to completion.
For project estimates, send scaled architectural elevation drawings to info@ssq.co.uk. For technical support, detailed specifications, or project consultation, contact us directly or visit our Professional Resources centre for case studies, CAD drawings, technical PDFs and additional support materials.
For maintenance queries and ongoing support, contact SSQ at 020 8038 6454 or email info@ssq.co.uk.
SSQ’s commitment to quality, backed by decades of natural stone expertise, ensures that Riverstone phyllite installations deliver exceptional performance and aesthetic results that enhance any building’s exterior for generations to come.
