A house in Sweden by Wingårdhs, featuring a spruce interior treated with Linolie & Pigment satin wood linseed oil. The oil is semi-transparent, revealing the wood grain beneath. Image Linolie & Pigment.

One of the largest timber structures in Denmark, Marmormolen by Henning Larsen under construction in 2024, is 8 storeys and 28,000 m2. It is constructed with glued laminated timber (glulam) and cross-laminated timber (CLT).

Spruce laminated veneer lumber (LVL) lamellas.

Yakisugi (焼杉), sometimes also known as shou sugi ban outside Japan, is a wood burning technique that has been used for centuries in Japan to extend the lifespan of wood in exterior applications. It was conceived before chemical treatments were available as a means of improving the longevity of wood by preventing decay, insect and mould infestation, while making planks more dimensionally stable and improving fire resistance. Typically used for siding and cladding on exteriors, the surface may be sealed and oiled for interior use, furniture and products.

Structural finger join in glulam engineered wood beams.

Superwood is spruce impregnated with fungicide and preservative to make it suitable for exterior use. Conventional impregnation applies force to liquid to treat the outermost layer of wood and so any cut or damage exposes the bare timber beneath. Superwood have developed a different technique, which allows them to apply treatment throughout the thickness of the timber, making it more efficient and effective. They take locally sourced spruce and apply the treatment using carbon dioxide (CO2) at temperature and pressure that causes it to become supercritical. In this state, there is no surface tension and the CO2 is able to pass through the wood without resistance, carrying the preservative chemistry and impregnating the wood from within. The colour of the wood is unaffected by the treatment, and will develop a typical silver patina over time, which allows light colour paints and stains to be used.

Superwood is spruce impregnated with fungicide and preservative to make it suitable for exterior use. Conventional impregnation applies force to liquid to treat the outermost layer of wood and so any cut or damage exposes the bare timber beneath. Superwood have developed a different technique, which allows them to apply treatment throughout the thickness of the timber, making it more efficient and effective. They take locally sourced spruce and apply the treatment using carbon dioxide (CO2) at temperature and pressure that causes it to become supercritical. In this state, there is no surface tension and the CO2 is able to pass through the wood without resistance, carrying the preservative chemistry and impregnating the wood from within. The colour of the wood is unaffected by the treatment, and will develop a typical silver patina over time, which allows light colour paints and stains to be used.

Peikko’s timber-based hybrid construction solutions include a range of standardised connections that enable connecting timber, steel and concrete seamlessly and reliably in large and heavy structures. In this case, a Bramco beam shoe on the end of the glulam beam connects with the Ramco hidden corbel in the vertical, multistorey column.

Thermory thermally modified timber (TMT) cladding, produced with spruce.

Laminated veneer lumber (LVL), with all the layers running parallel for maximum strength to weight along the length.

Spruce decking boards pressure-impregnated with copper-based preservative. It is not a durable material, and will not last long outdoors if left untreated.

Spruce decking boards. It is not a durable material, and will not last long outdoors if left untreated.

Gymnasium glulam roof structure in a gymnasium, by Flexwood

Expo roof, Hannover, Germany, completed 2000, designed by Herzog + Partner, featuring laminated veneer lumber (LVL), glulam triangular braces and solid silver fir uprights. Each of the ten 'umbrellas' covers an area of 1,600 m2 (40 by 40 m) and stands around 26 m high. The wooden elements are fixed together with steel brackets and castings. A waterproof membrane, suspended 50 mm above the roof, protects the wood from being permanently damp.

Oslo Airport, Norway, completed 1998, designed by Nordic Office of Architecture, features a glulam roof beams, supported by concrete and steel columns.

Olso Airport Train Station, completed 2017, designed by Nordic Office of Architecture, features a glulam roof structure.

Corrugated extruded polycarbonate (PC) glazing panel for exterior and interior applications. This system, Akrapan by Akraplast, features a tongue and groove profile to allow multiple panels to slot together, side-by-side. No junction profiles are needed, resulting in a uniform surface.

Courtyard door in pine before painting. Timber be used in load bearing applications is machine stress rated (MSR) - graded according to strength class. For example, C16 and C24. Graded timber is generally kiln dried (moisture content is reduced to required levels in a kiln), although can also be wet graded (which is moisture content at ambient levels and not kiln dried).

Timber frame house construction modules being assembled in a factory. Made from nailed pine frames, with oriented strand board (OSB) skins, they arrive on-site ready for installation. Lumber to be used in load bearing applications is machine stress rated (MSR). This is a non-destructive method used to check and validate the strength of the timber to a pre-determined load.

Violin front and back. The soundboard (front) is quarter-sawn spruce rough shaped ready for tuning, and the back is figured maple.

A swimming pool, built with spruce glulam beams and wood wool cement board (WWCB) panels. The interior is as it was, built 40 years ago - both material are resistant to the humid conditions and require minimal maintenance, if any.

Trus Joist (TJI) I-beams for timber frame construction, floors and pre-fabricated modules, produced in continuous lengths from laminated veneer lumber (LVL) with webs in oriented strand board (OSB).

Timber frame house construction modules being assembled in a factory. Made from nailed pine frames, with oriented strand board (OSB) skins, they arrive on-site ready for installation. Lumber to be used in load bearing applications is machine stress rated (MSR). This is a non-destructive method used to check and validate the strength of the timber to a pre-determined load.

Pfeifer cross laminated timber (CLT). This is a solid, multi-layer timber construction used for load bearing and structural applications. Image Pfeifer.

Finger jointed interior structure clad in oriented strand board (OSB).

Oriented strand board (OSB), also known as sterling board and flakeboard, wall cladding.

Presswood, or pressed wood, is a type of particleboard made up of various recycled wood products - fibre, flour, particles and chips - including damaged logs, wood waste and other wood byproducts. This helps to divert material from landfill. Utilised mainly for reusable pallets, the material is weather-resistant and durable. They are designed to be lighter than traditional hardwood pallets. At the end of its life the material can be recycled.


Cast concrete using wooden shuttering formwork faithfully reproduces the surface grain including knots and fixings. Partly painted grey.