The Löyly Masterpiece of Architecture Made from Small Diameter Wood

Victor Dela Casa
09 June 2021 33 min read



This blog post tells you the unique story of the Löyly. This masterpiece has received both praises and awards, such as the World's 100 Greatest Places to visit list by Time Magazine. Behind all this architectural success is also another success story worth telling. This story works as a starting point for the revolution that is going to take over the world of sustainable timber modification.

Keep on reading!

Sustainable Waterfront Timber Architecture

When Pekka Ritvanen, Avant Wood CTO, first met with the architects of Finland’s now iconic Löyly in 2016, he knew he had a solution that would solve a major challenge that the developers faced to complete the landmark project.  

The Löyly, a union of two Finnish passions -- sauna and timber architecture -- was to become the crown jewel of Helsinki’s waterfront. It was to mark the transformation of the area (Hernesaarenranta) from an industrial district into a sustainably-focused urban center. 


Thus, when the developers explained that the architecture will feature small diameter wood that otherwise would have been used in low-value applications, Ritvanen was confident that Avant Wood’s Thermo Mechanical Timber Modification (TMTM) is the perfect technology for the job. 


Thermal Wood Treatment and Mechanical Modification

Avant Wood’s TMTM™ technology is a one-of-a-kind and uniquely Finnish solution that merges thermal treatment and mechanical modification to quickly and efficiently improve wood properties. Even more important is its ability to utilize small diameter wood and softwood species, and alter their physical properties. With this ability, Avant Wood is able to use birch and pine as less expensive alternatives to harder species like oak. 

The idea was very appealing to the developers.  

WP_20160531_09_58_59_RichAgile Approach Leads to Success 

However, construction of the Löyly was to start in two weeks and Ritvanen had to source the wood parts needed and modify them to provide the test samples.  

He sourced the small-diameter birch wood in 2 days from local plywood producers. On the 3rd day, modification began. It took 2 days for the samples to be dried and another 2 days for final modifications.  

The preparation of the two 2-meter long table-sized samples lasted for 6 days. The developers tested the sample by sawing from various angles and were very pleased with the quality and the efficiency in the production of the wood samples.  


Avant Wood Supplies 6000 wood planks

After the deal was made official, Avant Wood supplied all the 6000 wood planks required to complete the project. Most of the planks were used on the exterior which serves like a towel over the glass building inside. It gave the Löyly character and the iconic wood aesthetics that changes color depending on the time of day and the weather. Avant Wood also produced the wood used for the doors, tables, and lockers. 

 (below) The exterior of Löyly is constructed by Avant Wood's unique TMTM™ technology.WP_20160531_10_16_27_Pro 

Small Diameter Wood Stores 279 tons of Carbon

The construction of the Löyly with its unique wood material is evidence that wooden buildings are a sustainable way to go. By using small diameter wood, the building was able to store approximately 279 tons of carbon. If the Löyly was made of concrete, it would have emitted 341 tons of carbon during the production of the concrete. This is a total carbon savings of 620 tons.

The efficiency of producing the wood is also an important point to make. Birch and pine are fast growing species that TMTM can modify to acquire similar strength and density properties as oak. In addition, TMTM can modify the wood 90% faster than conventional machines, which means fewer energy needed to perform the drying and wood densification. 

Smart? Sustainable Use of Wood

Pekka Ritvanen always says that when you have a sustainable way of using wood, you also have a smart way of using wood. Very true. 



Inspired? See the Case and watch the video: 

See Case Löyly Here

Carbon Calculations based on: