Healthy, sustainable, and efficient homes.

Architects, engineers and builders are realizing the potential of Dowel Laminated Timber (DLT) as a healthy, sustainable and energy efficient mass timber product. And it looks darn good!

Healthy, sustainable, and efficient homes.

All About Mass Timber

As the benefits of mass timber have become truly understood its use continues to grow in North America. If you’d like to learn more, use the buttons below to explore the topics.

What is Mass Timber?

Mass timber uses state of the art technology to connect layers of wood products together using either glue, nails or wooden dowels.

The resulting large structural panels are exceptionally strong and versatile and collectively known as mass timber. If the primary load bearing structure is made of solid wood it’s a mass timber building.

They can be pre-fabricated off site and installed quickly and efficiently and it makes a great complement to light and heavy timber framing options. It can be used to replace steel or concrete as a structural solution.

Types of Mass Timber

Not all Mass Timber products are the same! There are several different methods and mechanisms by which the timbers are formed. Here are the main ones:

Glulam - the wood layers are held together with glue

Nail Lam (NLT) - the wood layers are held together with nails

Dowel Lam (DLT) - the wood layers are held together with hard-wood dowels

All forms of Glulam, NLT and DLT can be produced as a stacked or crossed (CLT) product - not all CLT is glued, an incorrect term that has become widely used in the industry.

Benefits of Mass Timber

As the benefits of mass timber have become truly understood its use continues to grow in North America.

One of the greatest benefits of building with mass timber is wood’s ability to sequester CO2. As trees grow they capture CO2 from the atmosphere and store it in the wood. When trees are harvested for building materials, the carbon is captured for the life of the structure. In addition to storing carbon, wood products are associated with low levels of carbon emissions during manufacturing, (especially compared to concrete and steel) thus reducing the overall carbon footprint of a building’s construction. Combined with sustainable forest practices, mass timber could help to reduce the GHG impact of the construction sector.

By some estimates, the average carbon content of a tree is close to 50 percent of its total volume. Construction-grade lumber typically holds about 1 tonne of CO2 for each cubic metre of wood, while the average single-family home in Canada stores almost 30 tonnes of CO2 within the wood products used for its construction.

Because of their strength and dimensional stability, mass timber products are proving to be a practical alternative to traditional construction methods.

Lightweight and flexible, they have superior resistance to earthquakes for example. Mass timber systems are structurally comparable to steel and concrete but lighter. Mass timber projects utilizing wood instead of steel or concrete can have smaller, less expensive foundations, and are suitable for all soil conditions.

Because of its structural properties and dimensional stability mass timber is well suited to floor slabs, wall panels and roof / ceiling panels. The walls and floor panels may be left exposed in the interior which provides additional aesthetic attributes. Different compositions of mass timber can be used with light framing to provide lateral stability, thus allowing for greater building heights, or mixed structures.

Mass timber can be installed quickly and efficiently. Precise pre-fabrication off-site means an efficient construction process allowing structures to be built faster than ever. One of the biggest benefits of mass timber panels as compared to other types of construction is the ability to prefabricate the entire project. This saves precious time and money on-site because the installation process becomes more efficient.

Beauty and function can go hand-in-hand! There's no mistaking the pleasing aesthetic of wood. The energy of wood creates a sense of balance and calm, which can help create that oasis of peace and warmth in your home.

History of Mass Timber

The first forms of modern mass timber appeared in Europe in the late 19th and early 20th centuries and in the 1970’s in Switzerland mass timber as we know it today started to appear as NLT (nail laminated timber) and CLT (cross laminated timber) products.

With technological developments in design and production, mass timber grew and became established in Europe, arriving in and being accepted in North America around a decade ago.

DLT at International Timberframes

We believe wood is the most natural and healthy material to build with. We also understand that construction is a major contributor to waste. We must take whole-hearted steps to conserve our planet by doing everything as sustainably as we possibly can.

Therefore we design, manufacture and install a 100% wood DLT mass timber product called Wood100® DLT: no glue, no nails, just 100% wood. When you start adding layers of glue then many benefits are diminished, particularly in the areas of health and sustainability.

We have 25 years experience in mass timber, having worked on development of DLT in Europe in the 1990’s.

biophilia with dowl laminated timber dlt walls and ceiling in a commercial building

What is DLT?

To produce DLT, layers of wood are friction-fit together with hardwood dowels rather than glue or nails/screws. The dowels hold the boards together, the friction fit achieved by the differing moisture content of the softwood boards and the hardwood dowels.

The lumber layers are assembled into solid wood panels designed for walls, floor, ceilings and roof structures. Depending on the application, multiple layers of wood can be used to create panels up to 310mm thick. The resulting indestructible solid wooden blocks perform better than other construction methods at heat insulation, fire security, radiation shielding, earthquake safety and protection against condensation and mould growth.

After designing and pre-planning for location of windows, electrical and plumbing where relevant, the solid wood panels are pre-fabricated here in our shop. When the site is ready they are delivered and assembled quickly and efficiently.

Different Types of DLT

We produce 2 types of DLT: crossed and stacked. These 2 products have different strengths and appearances and therefore different applications. Below is the difference in the two at manufacture:

Sometimes it is the different aesthetic of each product that drives the choice of which one to use. However there are important differences between the two in terms of application and performance:

  • stacked DLT has higher structural values for ceilings and roofs
  • crossed DLT has higher structural values for shear walls and in seismic zones
  • crossed DLT offers superior thermal insulation over stacked DLT, NLT and glulam. It has almost double the R-value of any other solid wood product. This means that you can build a highly insulated wall in a similar thickness (14”)  to that of a regular framed house to reach a U-value of 0.2

Why we love (and make) DLT

Wood Fibre Board Insulation

To keep your Wood100®DLT home fully natural and sustainable, we also provide wood fibre board insulation. Wood fibre insulation is a safe, natural, and high performing alternative to many synthetic insulation options currently on the market.

We are suppliers of the Pavatex brand of wood fibre board insulation. These sustainable wood fibre boards are made from waste wood that is collected from various sawmills, heated and then pressurized.

The thermal insulation and carbon storage properties, and the easy handling format of the boards, mean that the material is ideal for use in a wide range of construction applications.

It is characterized by superior breathability, allowing moisture to move within a wall or roofing system and regulating it at safe levels to prevent it from entering the building fabric.

The advantages of wood fibre insulation such as Pavatex are crucial for the environment, building owners and contractors.

wood fibre board insulation on a DLT mass timber panel