Manufactured stone cladding: what to specify before you order

Manufactured stone cladding, also called concrete stone cladding, cast stone cladding or artificial stone cladding, is cast from pigmented concrete in moulds that reproduce the appearance of natural stone. Two walls clad with the same-looking stone can perform very differently depending on what is underneath, how heavy the stone is and how the corners are finished. This guide lists what to specify, in order.

1. The substrate

Concrete stone cladding is bonded to a sound, clean, flat substrate. What you check depends on the wall:

• rendered masonry: the render must be well bonded, with no hollow-sounding areas;
• concrete: clean, free of release agent and dust;
• external thermal insulation (ETICS): the most demanding case.

Insulation systems are assessed under different European Assessment Documents depending on the finish. Systems with renderings follow EAD 040083, currently version 040083-01-0404, adopted in 2024. Kits with insulation panels and a discontinuous outer cladding, such as clay units or stone, have a separate document, EAD 040287-00-0404 (EOTA, list of EADs).

In short: an insulation system assessed for a render finish is not automatically suitable for stone bonded over it. Ask the system supplier for the European Technical Assessment (ETA) and system instructions that cover a cladding finish, with their conditions: which units and how heavy, which adhesive, how they are fixed and on which substrate. The check applies to the whole build-up, in your project’s configuration.

2. Weight per m²

From Ristone’s product data, its 12 concrete stone models weigh roughly 20 to 49 kg per m² before adhesive: thin, flat models at the lower end, deep-relief models (1-4 cm thick) at the upper end. Natural stone weight depends on the rock and the slab thickness, so ask any supplier for a weight per m² for the exact product and thickness offered, and compare like with like.

These estimates use historical box weight divided by box coverage: Izmir is 20 kg/m² and Cumbria is about 49.1 kg/m². They exclude adhesive, jointing materials and corner pieces. Confirm the current figures for the chosen model in your quotation.

3. Thickness and relief

Declared thicknesses in the Ristone range run from 0.5-1.8 cm to 1-4 cm. Deeper relief casts stronger shadows and reads better from a distance, especially in raking light. Thickness also matters:

• at window sills, which must project beyond the cladding so water drips clear;
• at corners, where the edges of the units show;
• on clad piers, where the pier cap is sized to the finished pier, cladding included.

4. Corners

Corners are the most visible detail. In the Ristone range, five models have corner pieces: Alborz, Aurora, Bavaria, Cumbria and Himalaya. For the others, and for any natural stone, ask how corners are finished before ordering: cut and joined units, or another detail from the installation instructions.

5. Colour and batch

Ristone stone colours are, by model, glacier white, cream, sand brown and graphite, pigmented through the concrete. The actual shade can look different from photos because of light, screen and texture, and small differences between production batches are possible. Choose from a physical sample on your wall, in daylight, and order the full quantity for one elevation in one go, requesting the same production batch where available. More in our guide to colour and batches.

6. Documents

Ask for the current technical sheet, the installation instructions and the declaration of performance where the product has one; our checklist of technical documents explains each one. Natural stone cladding slabs are covered by EN 1469:2015 (BSI); ask a natural stone supplier for the documents relating to it. This standard does not cover artificially agglomerated stone, installation or fixing with mortar and adhesives, and does not certify Ristone concrete cladding.

What to send with your enquiry

1. the areas to clad, or an elevation sketch with openings;
2. the total height of external corners;
3. the substrate, and the name of the insulation system if there is one;
4. the model and colour, or two or three options for samples;
5. the delivery country and timeline.

For the UK, transport, customs duties and import VAT are paid by the buyer. See stone cladding or send your project enquiry.