The system
What sits against what, from the substrate outwards. Junctions, movement joints and edge details are project-specific — send us the drawings and we will mark them up.
In-situ rammed earth wall
Built on site in shuttering, compacted in lifts. Structural design is by the project engineer; we build to the approved mix and the approved mock-up.
Rammed earth finish (plaster)
Clayworks Rammed Earth Finishes. A clay plaster system laid in strata to read as a rammed wall, on a conventional interior substrate.
Performance data
Taken from the manufacturers' own technical data sheets, with the standard each figure was measured against. Product-level figures are on the product pages below.
| Property | Result | Standard |
|---|---|---|
| Applied thickness (finish) | 7 – 10 mm | Clayworks data sheet |
| Coverage (finish) | 1.2 m² nominal per 25 kg bag | Clayworks data sheet |
| Drying (finish) | 2 – 3 hours per layer, temperature and humidity dependent | Clayworks data sheet |
| Surface spread of flame | Class 1 | BS 476-7:1997 |
| Fire propagation | I = 0.5, i₁ = 0.0 — satisfies UK Building Regulations Class 0 | BS 476-6:1989 + A1:2009 |
| Noise reduction coefficient | 0.20 – 0.25 NRC, depending on backing board | BS EN ISO 354 |
| Impact | Impact diameter < 15 mm | BS EN 520 |
| Moisture buffer value | 1.28 — buffering measured at 9× painted plasterboard (University of Bath) | Nordtest method |
| Light reflectance value | Tested, data per colour on request | BS 8493:2008 + A1:2010 |
| VOC | Zero | Clayworks VOC emissions certificates |
| Embodied carbon | 0.048 – 0.068 kg CO₂e/kg (A1–A3) | Clayworks EPD, stages A1–A3 |
Products in this family
One page per technical data sheet. Each carries the manufacturer's declared figures, the limits, a specification clause and the full document set.
Where not to use it
Specifying a material into the wrong place is the most expensive mistake on a finishes package. These are the limits we will raise at review whether or not they are asked about.
- Interior walls, ceilings and fixed furniture. Bathrooms are appropriate; wet and shower areas are not.
- Not suitable for floors.
- Not to be applied directly onto timber, plywood, MDF or OSB.
- Not for doors or elements that will be moved.
- In-situ walls need a coping or overhang. Unsheltered heads erode.
- Colour and strata are set by the approved mock-up. Panel-to-panel variation is inherent to the material, not a defect.
Rammed earth finish: Clayworks Rammed Earth Finishes, applied 7–10 mm in strata to the approved mock-up, over Clayworks Wall Primer on the substrate scheduled. Colour and strata rhythm to the mock-up approved by the Architect. Fire performance to BS 476-7 Class 1 and BS 476-6 (I = 0.5, i₁ = 0.0), satisfying Building Regulations Class 0. Supply and application by Conmarble Natural Finishes as approved applicator. Glaze to exposed surfaces where scheduled.
Square brackets mark the choices that belong to the project. Send us the finishes schedule and we will return the clause completed, with the sample and mock-up programme against it.
Document library
Every publishable document for this family, reproduced in full and unaltered under our cover. Free to download, no form.
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Rammed Earth Finishes Rammed earth · Technical data sheet · 7 pp · 1.9 MBDownload (PDF, 1.9 MB)
Featured projects
Built with this material, by our own artisans. Open the project for the full set of photographs and the story of the installation.
Related systems
Technical support for the design team
We supply the material and we apply it, so the specification and the workmanship sit with one party. Send a finishes schedule, an elevation or a mood board and we will come back with the system, the build-up, the sample programme and a completed clause.