The log feed control room at Rauma sawmill is the first building in Finland to use completely new hybrid-sandwich wall elements. This innovation combines the best features of wood and concrete.
Together with its partners, Metsä Wood has designed a hybrid wall element for concrete manufacturers that combines concrete and Kerto® LVL. These elements are being used for the very first time in Metsä Fibre’s Rauma sawmill construction project.
Hybrid elements combine the best features of wood and concrete.
The Kerto® LVL panel forms the load-bearing structure in the construction of the wall element. The elements also have a layer of thermal insulation and a reinforced concrete facade panel. This means that the amount of concrete in the load-bearing wall elements is reduced by about two thirds, says Jussi Björman, Business Development Director at Metsä Wood.
“A 280-square-metre building has 14 sandwich elements. Their installation does not require vertical joint casting, sanding, and cleaning, which are typical phases for concrete wall elements. The entire process is faster.”
The elements are also an ecological choice. In Finland, approximately one million square metres of concrete-surfaced elements are used in construction each year. If this annual volume of concrete were to be replaced with hybrid elements, greenhouse gas emissions would be reduced by the equivalent of 30,000 tonnes of carbon dioxide. At the same time, the carbon sequestered by the elements would amount to an extra 95,000 tonnes of CO2 equivalents.
Wood is ecological and easily processed on site.
Wood is a strong part of the new Rauma sawmill
The total floor space of all the buildings at Metsä Fibre’s new Rauma sawmill amounts to roughly 44,000 gross square metres. Some of the largest buildings on site are the sawline, the processing lines, and the kiln drying department.
“The sawmill’s sturdy roof beams are made from glued laminated timber, and the roof elements are laminated veneer lumber ,” says Rauma sawmill’s Project Director Harri Haapaniemi.
“The interior design uses wood in ceilings and doors. Resting on concrete slabs, the sawmill’s beautiful pine floor adds flair to the walls, and timber brings a distinguished look especially in the office and staff facilities.”
With a length of 20 metres each, 24 beams make up the sawmill building’s 140-metre roof. In Haapaniemi’s view, there is a lot of wood at the saw mill which is sensibly joined with other materials. In selected applications, it is a better choice than other materials.
“The wood we use fulfils all the required construction standards with flying colours.”
Haapaniemi says wood is ecological and easily processed on site. Product development has achieved excellent acoustical properties and fire resistance.
This article was originally published as a part of a longer story in Timber Magazine issue 2022–2023.
