Forest Trees

25 September 2020

Why Dowel Laminated Timber?

2 minute read

The construction industry in Scotland has considerable experience in the use of platform timber frame in house building, but much less in the application of mass timber systems, despite several of the technologies involved having been in use in the UK for more than 20 years. At present, the bulk of the timber frame industry relies on imported material, with relatively little use made of the home-grown forest output for this purpose. 

Much of this is down to the historic misconception that the home-grown product is inferior and not suitable for construction, but research carried out over the past two decades into the characteristics and properties of the softwood species grown here (Sitka spruce, European Larch and Scots pine as well as Douglas fir) demonstrate that this is not the case and that the value of this resource can be raised considerably if manufactured into engineered timber products.

As a mass timber system, Dowel Laminated Timber (DLT) is unquestionably less well known than cross laminated timber (CLT) or Glulam but none of the three are in large scale commercial manufacture in the UK. Of these, the dowel lamination process is the least capital intensive to establish a manufacturing facility for and, due to the absence of glues and the curing conditions they require, is the only one suited to localised manufacture. 

Depending upon the lay-up arrangements of the timber lamellae in each panel, Dowel Laminated Timber is able to exhibit many of the same strength and stiffness characteristics found in its glued bedfellows and, in the context of local manufacture in remote rural locations, there are many good reasons for its use to be considered. These can be divided into two categories: the general properties that largely correspond to those of CLT and Glulam, and those that provide a distinct advantage over these systems as well as that of platform timber frame when local manufacture from the local forest resource in rural locations is considered. 

General Properties and Benefits of Mass Timber Systems

 

  • Solid timber panels, structurally robust

  • Durability

  • Thermal value

  • Airtightness standards

  • Simple, quick construction

  • Accuracy of construction

  • Minimal waste

  • Energy efficient

  • Embodied carbon efficient 

  • Exceptional carbon sequestration compared to other materials

  • Reduced foundations due to lighter weight of timber structure

  • Minimal on-site construction team required

  • Good internal air quality due to timber’s hygroscopicity

  • Excellent fire resistance (char layer)

Additional benefits of Dowel Laminated Timber

 

  • Doesn’t require large scale manufacturing facility and capital outlay

  • Sustainable manufacture and construction

  • No gluing (No VOCs)

  • Re-use at end of building life (circular economy) 

  • Stacked plank / cross laminated / diagonal laminated options (one-direction and two direction spans)

Benefits of local manufacture using mobile factory

 

  • Maximise use of local forest resource using mixed grades and species

  • High value product from low value timber

  • Local manufacture with no capital investment in equipment (lease/rent)

  • New skills for local communities (skills training in manufacture and construction)

  • Can be made in a mobile press - available when required

  • Small scale panels - no finger-jointing required 

  • Simple panelised wall, floor and roof build-up

  • No need for large scale plant (cranes etc)

  • Design flexibility with modular panels

  • Easy to calculate quantities

  • Reduced embodied carbon due to minimal transportation

The mobile factory concept makes the production of this normally offsite-manufactured modern method of construction possible onsite and close to the forest resource. With the creation of a mobile dowel lamination press, taking the factory to the forest can become a reality and a sustainable economic proposition for remote rural communities. 

dowel - lam

mass timber

mobile factory

Peter Wilson, Director, Timber Design Initiatives Ltd

Office

Timber Design Initiatives Ltd

90a Constitution Street,

Edinburgh,

EH6 6RP

+44 (0)131 554 8643

Quick Links

Keep in touch,

subscribe to our mailing list