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Portrettbilde av Bertil andersson, steinhugger hos Minera Skiffer Offerdal

– It’s great to be able to work on producing something that’s important for your hometown, and that also has a fantastic appearance.

Being born and raised in Lien, about a mile north of Offerdal in Jämtland, Sweden, it’s almost a given that slate will become part of your life. At least it was for Bertil.

Possibilities

Day after day, year after year, thousands of humans have walked on Offerdal slate. It will remain there, beautiful and unaffected by heavy traffic, water, acid and climate change.

Offerdal slate is ideal for everything from floor and bathroom tiles to steps or swimming pools.

Want to create a little extra magic? Use it outdoors on the façade of the house and enjoy the sight when the slate shows how it can reflect colour and the play of light through different seasons and times of day.

An entrance hall with gray slate in the hallway. Offerdal slate tiles on the floor provide a contrast to white plain walls.
Slate tiles in natural surface in the entrance hall |Offerdal slate
A cabin with dark timber walls and a large armchair. On the floor is gray crazy paving of Offerdal slate.
Flagstones as flooring indoors is beautiful and durable |Offerdal slate

Origins

In Offerdal, the landscape is dominated by forests that recede into the distance and and crystal-clear lakes. But its slate, hard-won from the rock has given the locals a vital livelihood since the late 1940s.

Like Otta and Oppdal, the inhabitants of Offerdal are also keen to use their slate in the area close to the quarry. So Offerdal slate can continue to play an important role locally while saving the environment from the burden of a long transport route.

Life Cycle

After 650 million years at one with nature, Offerdal slate has a strength and durability that impresses even the most hardy of us.

Offerdal slate is very suitable where other natural materials often fall short. Extreme loads such as heavy traffic, frost and climate change make no impression on this slate from Jämtland, which, despite its proven strength, remains beautiful to look at – and will continue to do so for many generations to come.

2 men working with natural stone in the slate quarry of Offerdal.

Projects 

With the aim of achieving the goals of the Paris Agreement and the goals for climate neutrality, it’s important to choose materials with the lowest possible environmental impact.

That’s why Henning Larsen Architects chose Offerdal slate, based on its low environmental footprint, when they designed the new Nordea Bank headquarters in Copenhagen. This green prestige project was subsequently awarded the highest possible environmental certification: LEED Platinum.

Slate tiles of Offerdal slate on the floor and wall in Nordea's new head office in Copenhagen
Nordea HQ, København, Denmark | Henning Larsen Architects
Slate tiles of gray slate from Offerdal and light gray slate from Oppdal in a sculpture fountain at Kistefos Museum.
Kistefos Museum, Norway | Artist: Jeppe Hein
Facade panels in gray Offerdal slate on a modern facade at Vanabbe Museum in the Netherlands.
Van Abbemuseum, Eindhoven, the Netherlands | Architect: Abel Cahe

The façade of Offerdal slate at the Van Abbemuseum in the Netherlands is an impressive sight as it changes with the light throughout the day. The waved, light-reflecting surface of the Offerdal slate is a small work of art in its own right, which the artist Jeppe Hein highlighted in his sculpture “The Road to Silence”, which you can admire in the sculpture park at Kistefos Museum, Norway.

As humans, we are “grounded” in nature, and we like to surround ourselves with it. Slate is a living material that ages with dignity and gives warmth to any interior. Perhaps this is the reason that well-known wellness hotels such as Copperhill Mountain Lodge, Palanga Design and Spa Hotel and Falkenberg Strandbad have used Offerdal slate in various forms and in everything from bars and reception areas to pools, saunas and fireplaces?

Slate tiles of gray slate on the floor from Offerdal in a modern room with wood at the University of Uppsala.
DTU Life Science and Bioengineering, Copenhagen, Denmark | Christensen & Co. Architects + Rørbæk of møller Arkitekter
A large fireplace in bricks of gray Offerdal slate mounted as a dry wall at Copperhill Mountain Lodge.
Copperhill Mountain Lodge, Åre, Sweden | Architect: AIX og Bohlin, Cywinski Jackson
Offerdal outdoor tiles of gray slate that forms a pattern on the new main square in Trondheim.
Torvet in Trondheim, Norway | Agraff Arkitektur

The combination of art and sustainability is also why Offerdal slate was chosen as the paving for Torvet, the main square in Trondheim, Norway. The slate forms a pattern inspired by local patterning tradition and was designed by the artist Edith Lundebrekke.

A main square should be a vibrant and pulsating urban space and requires strong materials! Østersund Square in Sweden, paved with Offerdal slate, is used for everything from markets and concerts to sledging and skiing.

Frequently asked questions about slate

It has an unlimited lifespan. For a natural stone to have a long lifespan, it must have a mineral composition that makes it weather-resistant. Our slate consists of highly durable minerals. In addition, they have a mineral structure that is dense and thus strengthens its technical properties. Our three types of slate are positioned within the top 10 in the world in terms of durability.

Our slate is from Norway and Sweden, and all production is done locally by our stonemasons. Slate is split by hand into its natural layers, unlike marble and granite, which are cut mechanically into sheets using a multi-blade saw. However, with a lifespan of > 100 years, slate is often a cheaper alternative in terms of lifespan. The installation cost is largely the same, whether you choose slate or an affordable material.

Slate is a 100% natural material. Our slate from Otta, Oppdal and Offerdal consists of highly durable minerals such as quartz, felt spat and mica. The minerals have a favourable structure that is dense and further strengthens its qualities. Through pressure and temperature, the deposition of sand and clay in rivers and on the seabed has been transformed into rock slate for hundreds of millions of years.

You save the environment from a more than 700% increase in CO2 emissions compared to a ceramic copy. Genuine slate tiles can be supplied with falling lengths that create a beautiful floating look. This format cannot be achieved by using ceramic copies. Choosing local genuine slate also supports sustainable production and local value creation.

The quality of Scandinavian slate is unrivalled. There are old types of rocks where time, pressure, temperature and transformations have developed the slate types into solid materials. The ice ages also contributed to removing much of the younger and weaker rocks that were originally above the slate sites we have today. Most types of slate from other parts of the world are younger, they have not been exposed to temperature, pressure and transformation in the same way as the Scandinavian slate types. Norwegian slate is also local and has a high degree of handicraft – which combined give it a record low environmental footprint.

Minera Skifer has three slate quarries, two in Norway and one in Sweden. Oppdal slate is light grey, the slate from Otta in Gudbrandsdalen is black or rust-coloured, and the slate from Offerdal in Jämtland is deep grey.

Yes, slate is a 100% natural material. Hundreds of millions of years ago, sediments of sand, clay and gravel sank to the bottom of the sea. There it was pressed together into layers, before it became slate under high pressure. Our slate is extracted from Norwegian and Swedish mountains and refined by local stonemasons right at the foot of our three slate quarries.

Yes, local slate from the Scandinavian region has an extremely low climate footprint. It is a 100% natural material that is largely processed by hand, requires minimal maintenance, is everlasting, and can be recycled and reused.

Light Oppdal slate is a medium-grain, rock-speckled gneis mica quartzite slate. Otta slate is a dark slate from the type of rock called Phyllite slate. Offerdal slate is a quartzite from the rock type felt spat metasandstone.

For a slate to have a rust colour, a slate type that can develop a rust patina must be used. In Scandinavia, only Otta slate from Gudbrandsdalen in Norway has a mineral composition that provides this property. Rust develops naturally over time due to weather and wind, and becomes increasingly beautiful over years.

Read about Otta slate’s development of a beautiful rust patina here.

No, our slate must not be impregnated. However, for some applications, it would be advisable to recommend impregnation, as it provides protection against stains and dirt while also facilitating cleaning. For example, it is a good idea to impregnate worktops that are exposed to grease spills, etc.

Yes, slate has very good breaking strength and flexibility. For driving on slate laid in cement mortar or on concrete slabs, the slabs should be at least 2 cm thick. If the slate is laid in gravel, the surface should be stable, well compressed and frost-free, and the slate should have a minimum thickness of 4 cm.

No. Our three slate types in natural surfaces are 100% non-slip (with the highest classification) and are therefore very suitable for external areas such as terraces, staircases and the like. We also supply slate in finished surfaces that are non-slip. All our slate surfaces have been tested and the slip resistance has been documented with an R number, which is a standard for testing slip resistance and is used for ceramic tiles, among other things. See our product datasheets for test results.

Yes. Our slate from Oppdal, Otta and Offerdal is all 100% frost-proof and therefore very suitable for use in a tough Nordic climate.  The porosity of a material is calculated by measuring the maximum amount of water that it attracts. In general, porous materials with high water uptake are the least strong and durable. All of our slates have water uptake far below what the European standard states as a limit for frost protection (NS-EN 12326-1: water absorption ≤ 0.6). See more in our product datasheets here

Yes. Our slates are water-resistant and can be installed in pools, fountains and the like. With a very low level of water absorption, they are therefore also 100% frost-proof.

Yes, Minera Skifer’s three types of slate can withstand salt. However, over time, large quantities in humid climates can affect the minerals and cause a colour change in the surface– a patina. This has no impact on the technical quality of the slate, i.e. the function, durability and lifetime remain unaffected.

Yes. Our slate is non-slip and can withstand moisture and chlorine from a pool. Offerdal slate is particularly suitable for this (test-documented), and has been widely used for this purpose in Europe for decades. Our three types of slate can all be used both in the pool itself or around the pool. Otta slate and Lys Oppdal slate should be avoided in the actual zone transition between water and air.

Yes. It is a good idea to lay outdoor heating cables under slate that is glued on concrete or laid in gravel.

This is contingent on insulation under the heating cables. There are, among other things, heating cables mounted on insulating mats intended for this purpose.

 

 

No. Slate in its natural surface can withstand studs and have no unfortunate consequences. On floors where the surface of the slate is either brushed or sanded, we do not recommend the use of studs.

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