R 11
0.1 weight%
1.69 CO₂-EQ
46.2 MPa
A natural, gently wavy and highly light-reflective surface in a deep grey tone.
The slate is extracted from a large deposit in the bedrock between Rönnöfors and Finnsäter, near the Norwegian-Swedish border. The natural surface is created when the stone block is split by hand along natural layering without further treatment. All subsequent processing of format and thickness takes place locally at the quarry, ensuring consistent quality and a minimal climate footprint.
| min – max (mm) | min – max (mm) | min – max (mm) | |
| Length | Width | Thickness | |
| Rectangular, random lengths | 300 – 2500 | 100 – 1000 | 8 – 80 |
| Rectangular, fixed lengths | 300 – 2500 | 100 – 1000 | 8 – 80 |
| Square | 100 – 1000 | 100 – 1000 | 8 – 80 |
| Irregular | 400 – 2000 | 250 – 1500 | 5 – 130 |
| Wall bricks | 150 – 1500 | 25 – 450 | 25 – 200 |
| Natural | |
| Hewn | |
| Scissored | |
| Sawn | |
| Brushed | |
| Honed |
| Tiles for wall and floor (indoor) | |
| Paving tiles (outdoor paving) | |
| Outdoor slate tiles | |
| Outdoor tiles for pedestal system floors | |
| Flagstones | |
| Stepping stones | |
| Stair treads | |
| Steps | |
| Massive landscape steps | |
| Countertops and slabs | |
| Wall bricks | |
| Natural/dry wall | |
| Machine stone (blocks) | |
| Facade panels | |
| Window sills |
| mm | |
| Thickness/depth | |
| Indoor wall/floor | 8 – 20 |
| Pedestal floors (indoor/outdoor) | 20 – 25 |
| Outdoor paving | 10 – 80 |
| Pedestrian traffic | 10 – 30 |
| Light vehicle traffic: | 20 – 60 |
| Heavy vehicle traffic | 40 – 80 |
| Roofing | 8 – 35 |
| Facade panels | 8 – 35 |
| Glued on steel/aluminium profiles | 8 – 12 |
| Screwed or hooked overlapping on steel/wood battens | 8 – 12 |
| Mechanically fastened on back to profiles | 15 – 25 |
| Mechanically fastened with dowels in edge to profiles | 32 – 35 |
| Wall brick facade | Djup |
| Dry wall / natural – small wall brick: | 50 – 200 |
| Dry wall / natural – large wall brick: | 150 – 300 |
| Thickness [mm] | Weight per sqm [kg] |
| 10 | 27 |
| 12 | 33 |
| 15 | 40,5 |
| 20 | 55 |
| 25 | 67,5 |
| 30 | 81 |
| 40 | 108 |
| 50 | 135 |
| 60 | 162 |
| 10 – 20 | 50 |
| 20 – 30 | 67,5 |
| 30 – 40 | 100 |
| 40 – 60 | 135 |
| 60 – 80 | 190 |
| Minera Råkopp (dry wall), depth 50 – 200 | 400 |
| Minera Råkopp (dry wall), depth 150 – 300 | 500 |
| Density | 2712 g/m3 |
| Water absorption [weight%] | 0,11 |
| Flexural strength [MPa] | 46,2 |
| Slip resistance | R11 |
| CO₂ emissions [kg CO₂ eq. per sqm, t: 12 mm] | 1,60 |
| The mineral composition explains the technical performance and homogeneous appearance of Offerdal quartzite. This is a fine-grained quartzite slate with a high mica content and low porosity, which gives great dimensional stability and durability. | |
| Quartz | 39% |
| Provides high wear resistance and low water absorption. | |
| Mica | 42% |
| Affects cleaving 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 in this proportion. | |
| Plagioclase | 2,2% |
| Part of the mineral grain structure, without significant effect on performance. | |
| Ilmenite | 1,2% |
| Occurs in small amounts. No practical relevance to appearance or properties. | |
| Zircon | 0,2% |
| Trace element without impact on function or appearance. | |
| Calcite | 0,1% |
| Trace content without measurable influence on material properties. |
| Petrography: | |
| Quartzite | |
| Origin | |
| Offerdal in Krokom municipality, Sweden | |
| Material description for facade and floor, outdoor and indoor: | |
| Light grey, cleavable quartzite slate in natural layers providing a matt surface with natural colour variation similar to Offerdal slate from Finnsäter | |
| Splittable natural stone with distinct layers or zones in different colours | |
| Some variation in grey tones from tile to tile (or brick to brick) is desired to create a lively, natural look | |
| Flexural strength over 45 MPa | |
| Water absorption max 0.1 percent | |
| Slip resistance equivalent to minimum R11 | |
| Durable and long-lasting | |
| Long-term delivery security and documentation requirements: | |
| EPD for life cycle assessments and CO₂ calculations | |
| History of retained technical performance over time despite development of patina | |
| Reuse potential (if functional requirements otherwise permit) | |
| Long-term managing plans | |
| Future access to the same visual expression and technical qualities | |
| Established routines for testing and quality control | |
| CE marking | |
| Reference projects | |
| Access to technical support and advisory | |
| Other material requirements: | |
| Must be a natural material | |
| The material should reflect the history and/or location of the project | |
| See also reference projects for desired expression |
Place of origin Offerdal in Krokom municipality, Sweden Petrography Quartzite slate
Offerdal natural surface: Light grey quartzite slate in natural layering providing a natural surface equivalent to Offerdal slate from Finnsäter.
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