The roof of the new Museum of Viking Age on Bygdøy is covered with Otta slate. It has been an incredibly exciting project, not least because the roof is curved and double-curved, and the ridge has a height difference of 2.5 meters. The solution was therefore to lay the slate slabs with a large overlap.
Ottaskifer is used, and 20% of all the stone is Ottaskifer rust. All the slate is extracted from the Pillarguri quarry here at Otta. Extraction takes place all year round, from the hottest summer days to sub-zero temperatures that creep down to 30°C. The first stone was delivered in October 2024, and by the end of April 2025 all stones had been delivered. The museum will be ready for visitors in 2026.
The day we were told that the assignment was ours, there was a big celebration in the production hall, and the pride was palpable. A delivery of such dimensions requires extreme knowledge, craftsmanship and accuracy, and the entire delivery value chain is local. As a small production company in Gudbrandsdalen, it’s really cool to be noticed on a national (and international) level! It’s even more rewarding to know that government clients choose local suppliers and genuine Norwegian raw materials that will last for generations.
Then we quickly landed on our feet as we realized the extreme complexity of what such a delivery entailed: This is a large and demanding project with a delivery of 54,706 slate slabs in six months. The slate tiles were produced in 30 different sizes for both roofs and facades, so the production was intensive in several ways: the production itself was complicated, the packaging was complicated and the logistics more complicated. Not a single stone was delivered late and not a single error or defect was registered. We managed the production by running efficient daytime operations only, and therefore avoided 24-hour shifts.
What’s more, all the slate is hand-nailed, with as many as 110,000 holes punched at the construction site! This roof is proof that old building techniques go hand in hand with modern architecture.
The architects had decided that the slate should not have a fixed pattern, which meant that laying the slate was somewhat more complicated because it had to be ensured that no patterns were created along the way.
Prior to installation, the slate was tested for temperatures down to 20 below zero. Slate is one of nature’s most durable materials and is ideal for harsh weather conditions.
The spectacular slate roof is now complete and will develop a stunning patina over the years. This is something to look forward to observing in the future!
