R10
0.1 weight%
3.02 kg CO₂
47.6 MPa
A brushed and even surface with a hint of texture, a subtle sheen, varying grey tones and a rustic character.
The slate is quarried from a large slate deposit in the mountain between Rönnöfors and Finnsäter, close to the border between Norway and Sweden. The surface is brushed to a beautiful antique patina, where a subtle trace of the natural slate texture is preserved, while remaining easy to maintain and clean. The brushing, as well as further adjustment of format and thickness, is carried out locally at the quarry, ensuring consistent quality and minimal climate impact.
| min – max (mm) | min – max (mm) | min – max (mm) | |
| Length | Width | Thickness | |
| Rectangular, random lengths | 300 – 2500 | 100 – 600 | 10 – 50 |
| Rectangular, fixed lengths | 300 – 2500 | 100 – 600 | 10 – 50 |
| Square | 100 – 600 | 100 – 600 | 10 – 50 |
| Sawn | |
| Brushed | |
| Honed |
| Wall and floor tiles (indoor) | |
| Outdoor paving | |
| Outdoor tiles | |
| Outdoor tiles for pedestal systems | |
| Stair treads | |
| Countertops and slabs | |
| Facade panels | |
| Window sills |
| mm | |
| Thickness/depth | |
| Indoor floors/walls | 8 – 20 |
| Pedestal flooring indoor/outdoor | 20 – 25 |
| Outdoor glued paving | |
| Pedestrian traffic | 10 – 20 |
| Facade panels | 8 – 35 |
| Glued to steel/aluminium profiles | 8 – 15 |
| Slate overlap w/ screws or hooks on steel/aluminium/wood battens | 8 – 15 |
| Mechanically fixed on back to profiles | 15 – 25 |
| Mechanically fixed with dowels in slate edge to profiles | 32 – 35 |
| Thickness [mm] | Weight per m² [kg] |
| 10 | 27 |
| 12 | 33 |
| 15 | 40,5 |
| 20 | 55 |
| 25 | 67,5 |
| 30 | 81 |
| 40 | 108 |
| 50 | 135 |
| 60 | 162 |
| Density | 2740 g/m3 |
| Water absorption [weight%] | 0,1 |
| Flexural strength [MPa] | 47,6 |
| Slip resistance | R10 |
| CO₂ emissions [kg eq. per m², t: 12 mm] | 3,02 |
| The mineral composition explains the performance and homogeneity of Offerdal quartzite slate. This is a fine-grained quartzite slate with high mica content and low porosity, providing dimensional stability and durability. | |
| Quartz | 39% |
| Provides high wear resistance and low water absorption. | |
| Mica | 42% |
| Affects cleavage and surface; gives a homogeneous, fine-grained appearance. | |
| Feldspar | 8% |
| Contributes to colour tones and increases chemical stability. | |
| Epidote | 2,5% |
| No visible or technical effect at this proportion. | |
| Plagioclase | 2,2% |
| Part of mineral grain structure; no significant performance effect. | |
| Ilmenite | 1,2% |
| Occurs in small amounts. No practical impact on appearance or properties. | |
| Zircon | 0,2% |
| Trace element with no influence on function or appearance. | |
| Calcite | 0,1% |
| Trace content with no measurable impact on the material’s performance. |
| Petrography | |
| Quartzite slate | |
| Place of origin | |
| Offerdal, Krokom municipality, Sweden | |
| Descriptions of material for facades and flooring, indoor and outdoor: | |
| Mid-grey quartzite slate in natural layering with an even surface where natural height variation can be seen and clearly felt upon contact. The expression is achieved through a unique brushing technique using tools with varying grit. | |
| Splittable natural stone with distinct layers or zones showing varying colour tones | |
| A certain variation in greys from tile to tile is desirable to create a lively, natural appearance | |
| Flexural strength above 45 MPa | |
| Water absorption max 0.1 percent | |
| Slip resistance minimum R9 | |
| Durable and long-lasting | |
| Long-term delivery security and documentation requirements: | |
| EPD for life cycle assessment, CO₂ calculations | |
| Proven long-term technical qualities, unchanged over time despite patina development | |
| Reusability potential (provided functional specs allow) | |
| Long-term operational plans | |
| Future access to the same visual and technical qualities | |
| Established routines for testing and quality control | |
| CE marked | |
| Reference projects | |
| Access to technical support and advisors | |
| Other requirements for material: | |
| Must be a material of natural origin | |
| Material should reflect the project’s history and/or location | |
| See reference projects for desired visual expression |
Place of origin Offerdal, Krokom municipality, Sweden Petrography Quartzite slate
Offerdal antique brushed surface: Mid-grey quartzite slate in natural layering with an even surface where natural height variation can be seen and clearly felt upon contact. The expression is achieved through a unique brushing technique using tools with varying grit.
We offer architects material samples, advice and inspiration for projects of all sizes. Explore our full product range, visit the quarry, or book a tailored presentation – either in person or online. Together we’ll find the best solution for your project.
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