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GLT by Stora Enso

Glued laminated timber (GLT)

Exceptional strength and visual appearance

Glued-laminated timber (GLT/Glulam) is often used in long-span designs, where it can replace steel and concrete in beams, columns, and other load-bearing structures.

Photo: courtesy of Lendlease

What is GLT?

Glued-laminated timber (GLT) or Glulam are different names for the same mass timber product. It can be produced in a wide range of shapes and sizes up to impressive heights and widths.

GLT by Stora Enso is made of strength graded, planed and finger-jointed spruce boards glued together under pressure on their flatwise surface where all boards run parallel to the length to create rectangular cross-sections.

Why GLT by Stora Enso?

GLT is commonly used in projects where both strength and visual appearance are important. Because of its stability, GLT by Stora Enso does not twist or bend and has highly predictable moisture and fire resistance properties. 

GLT by Stora Enso that is customised and delivered just-in-time (JIT) is part of our Sylva™* kit, where it is used in Sylva GLT Beams and Columns

We work closely with trusted partners to manufacture Sylva™ Beams and Columns from GLT.

*Sylva™ by Stora Enso is currently only available in Europe and Australia.

Technical product description

GLT by Stora Enso is made by bonding multiple finger-jointed layers of strength-graded boards together with high-strength adhesive. It can be produced in both standard sizes and custom dimensions to suit long-span designs. To fit the needs of different projects, GLT by Stora Enso is available in visual grade and a more economical industrial grade.

Beam lay-ups

Sylva GLT Beams are made from the strongest parts of the tree, which makes them considerably more sturdy than solid sawn beams of the same size. Depending on budget and requirements, Sylva GLT Beams can be manufactured as homogenous boards (GLh) or combined boards (GLc).

Homogenous boards consist of the same strength of wood throughout, whereas combined boards are manufactured with a mixture of strengths. Higher-strength grade boards are placed in the outer zones and lower-strength grade boards in the inner zone.

All Sylva GLT Beams and Columns are CE-marked and manufactured according to EN 14080 standard.

Block glued GLT

Block-glued GLT by Stora Enso is a structural member with a solid rectangular cross-section that comprises two or more GLT components bonded together with a structural adhesive.

GLT by Stora Enso technical product description

 

 

Benefits of designing and building with GLT (glulam)

  • Prefabrication allows you to build more quickly and cost effectively

  • Made from solid wood sourced from sustainably managed European forests

  • Low embodied carbon content compared to steel and concrete

  • Flexibility—GLT is available in a wide range of widths and heights

Applications

The most efficient and economical use of Sylva GLT Beams and Columns is in buildings with a grid in the range of 5–7.5 m x 5–9 m. This layout allows efficiency in the design. 
GLT by Stora Enso applications

Image gallery

International House Sydney, Australia
International House Sydney, Australia
Photo: Lendlease, Developer: Lendlease, Architect: Tzannes Associates
International House Sydney, Australia
International House Sydney, Australia
Photo: Lendlease, Developer: Lendlease, Architect: Tzannes Associates
International House Sydney, Australia
International House Sydney, Australia
Photo: Lendlease, Developer: Lendlease, Architect: Tzannes Associates
International House Sydney, Australia
International House Sydney, Australia
Photo: Lendlease, Developer: Lendlease, Architect: Tzannes Associates

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Product range and features

Grade

GL24h, GL28c

Width, B [mm] Widths
up to 260 mm in increments of 20 mm
Height, H up to 1200 mm 100 120 140 - - 260
120 GLT beam and column
160
200
-
-
-
-
-
-
-
In increments of 40 mm -
1,200

Lengths up to 18,000 mm

Grade

GL24h, GL28c

Width, B [mm] Block-glued widths
from 280 mm up to 600 mm in increments of 40 mm
Height, H up to 1200 mm 280 320 360 - - 600
280 GLT beam and column
320
360
-
-
-
-
-
-
-
In increments of 40 mm -
1,200

Lengths up to 18,000 mm

Standard variants

Species: Spruce

Strength classes: GL24h, GL28c

Cross-sections: rectangular, linear elements

Surface quality: visual (VI) and industrial quality (IVI)

 

Standard product range

*80–260 mm in width in increments of 20 mm, block glued from 280 mm up to 600 mm in increments of 40 mm

*up to 1,200 mm in height increments of 40 mm

*18,000 mm in length

 

* Other dimensions and strength classes can be made available upon request. Please contact your local sales representative for more information.

Surface qualities

GLT by Stora Enso is available in two different surface qualities, depending on your requirements.

  • Visual (VI): The best possible surface quality is used when the product will be exposed and featured as part of the interior design of the building. This grade is often used in public buildings, schools, or homes.
  • Industrial quality (IVI): Suitable for exposed surfaces in industrial or commercial buildings where the conditions are not the most demanding. 

Learn more about the criteria and how visual and industrial qualities are categorized

Reference projects

International House Sydney
Photo: Lendlease

International House

Sydney, Australia
Learn more
Charterhouse school
Photo: Design Engine

Charterhouse School

Surrey-Godalming, UK
Learn more

Browse over 500 wooden buildings and get inspired

Explore references

Technical product data

Key data

Service class Service class 1 and 2 according to EN 1995–1–1
Product certification CE-marked, manufactured according to EN 14080
Strength class GL24h, GL28c
Moisture content 12 % ± 2 % (max 15%)
Wood species Spruce
Weight/Density 420kg/m3 (GL24h), 420 kg/m3 (GL28c)
Reaction to fire class Euroclass D–s2, d0
Reaction to fire, charring rate βn=0.7 mm/min (notional charring according EN 1995–1–2)
Thermal conductivity 0.13 W/(mK)
Water vapour transmission resistance 40 µ

Adhesives and emissions

GLT by Stora Enso is made by bonding multiple finger-jointing layers of strength-graded boards together with an MUF type 1 adhesive. The adhesive meets the requirements of class E1 (EN 717–1) with formaldehyde emissions <0.1 ppm. This results in very low volatile organic compounds (VOC levels) where GLT by Stora Enso meets the most demanding indoor climate requirements.

Fire performance

GLT by Stora Enso meets fire regulations. When timber is exposed to heat, a thermal breakdown process occurs and a layer of char forms on its surface. Wood has around a 10–12% moisture content, depending on the building’s internal atmosphere. The charring process begins when timber ignites, and the moisture evaporates. This charred layer is a natural insulator that protects the inner core. 

The surviving structure in the uncharred inner core remains relatively unaffected, maintaining its structural strength and stability. Typically, a wood structure can remain stable for two hours when exposed to a fully developed fire.

Tolerances

GLT by Stora Enso is manufactured in a modern, controlled environment and cut to size with highly accurate CNC processing. Exceptional size accuracy minimises the need for remedial work when the prefabricated elements are delivered on site, which speeds up the building process and reduces construction costs.

Element length  +/- 2.0 mm
 Width  +/- 2.0 mm
 Height h < 400 mm, -2 mm to + 4 mm
h > 400 mm, -0.5 % to 1%

Dimensional stability

Wood shrinks or swells as its moisture content changes but in GLT by Stora Enso this is minimal because of the lamination process. Standardized values according to EN 14080 are:

Direction  % of shrinkage or swelling per % moisture change
Grain direction  +/- 0.01
Cross-grain direction   +/- 0.25

Calculatis: a state-of-the-art timber design tool

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Sustainability

Sustainably sourced and manufactured GLT

 
The energy used for manufacturing GLT by Stora Enso is very low compared with traditional construction materials. GLT by Stora Enso is lighter than steel which means fewer shipments are needed for transport resulting in lower transport emissions. 
 
GLT by Stora Enso is always sourced from responsibly managed forests and the harvested wood is duly regenerated. Stora Enso uses third-party certification under FSC® and PEFC Chain of Custody which ensures full traceability of the raw material from sustainably managed forests.
 

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