Dowel Laminated Timber (DLT)

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If you care about energy efficiency, health and sustainability then our 100% wood dowel laminated timber, DLT, could be ideal for your residential or small business project.

There’s probably not a week goes by when you don’t hear or read about Mass Timber.  It’s heralded as the biggest, newest innovation in added value wood products.  

It’s not really a new product: it has been around in Europe for several decades and the market there is fairly mature.  We are lucky to be able to benefit from their years of experience and learning.

Architects and engineers are excited about the structural values of mass timber and its ability to replace steel and concrete as a structural solution in tall buildings.  Much of the application we see in North America is in large commercial and industrial buildings.  However we believe the benefits of mass timber are just as applicable and achievable in smaller scale commercial and residential buildings.

dlt-residential

What is mass timber?

Mass timber is any large structural panel (for walls, floors, ceilings or roofs) made by connecting layers of wood products together using either glue, nails or wooden dowels.

If the primary load bearing structure is made of these panels they are called mass timber buildings.  Exceptionally strong and versatile they can be pre-fabricated off site and installed quickly and efficiently. It makes a great complement to light and heavy timber framing options. 

 

Types of mass timber

When the wood layers are held together with glue the mass timber is known as glue laminated timber (glulam)

When the wood layers are held together with nails the mass timber is known as nail laminated timber (NLT) 

When the wood layers are held together with hard-wood dowels the mass timber is known as dowel laminated timber (DLT)

 

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.

As the benefits of mass timber have become truly understood its use continues to grow in North America.  GC Wood has just published an extensive report on Mass Timber in Canada which you can enjoy at your leisure by clicking here.

Stacked-DLT

Benefits of mass timber 

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.

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.

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.

Mass timber is capable of maintaining load bearing capacity in the event of fire, as the  large wooden blocks char on the surface rather than burn completely, allowing for more time to evacuate and extinguish fires.

sustainable natural mass timber dowel laminated wood

Dowel Laminated Timber (DLT)

We love mass timber and manufacture only 100% wood dowel laminated timber – our product is called Wood100ⓇDLT.   We do not believe mass timber requires glue or nails, especially when the benefits are better without!

 

Producing Wood100ⓇDLT

To produce dowel laminated timber, DLT, layers of softwood boards 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 dowel 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 360mm 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.  

2 different types of Wood100ⓇDLT

We manufacture 2 types of dowel laminated timber, DLT: stacked and crossed. These 2 products have different shear strengths and finishes and therefore different applications. 

Stacked DLT

stacked-DLT

These panels are manufactured by stacking the wood layers on top of or next to each other on edge in the same direction as the previous and pegging them together with beech dowels

People wrongly assume that all DLT is stacked.

 

Crossed DLT 

crossed-DLTThese panels are manufactured by cross laminating 3 to 7 layers of softwood lumber.  The panels are made by layering wood on top of each other on their wide edge at alternating angles and pegging them together with beech dowels.

 

 

 

 

 

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    

types-of-dlt

We designed, manufactured and installed this beautiful small garden studio office using a combination of crossed DLT walls and stacked DLT ceiling and roof.

dowel-laminated-office

Superior benefits of Wood100ⓇDLT

Environmental sustainability / recyclability

dlt-interiorOur 100% Wood DLT contains no glues or other chemicals making it 100% uncontaminated and therefore 100% recyclable wood. It can be disassembled and re-used or composted at the end of its life. The energy consumption during manufacture of our DLT is roughly 3.5 times lower than in the manufacture of other mass timber products. This significantly lowers production emissions.  We are proud to make a 100% wood, 100% re-usable, 100% recyclable product.  Incorporating Wood100ⓇDLT into your home or office project demonstrates authentic sustainable thinking and action.

Energy Efficiency

residential-dltWood’s low thermal conductivity provides natural insulation that reduces heat transfer. A solid DLT home has the world record for heat insulation in structural materials and therefore minimal operating costs.  Recent tests of 3 wall systems with the same R-value showed the supremacy of crossed DLT.  An average Wood100ⓇDLT home needs ⅓ of the heating system compared to a traditional framed home with the same R-value.  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

It’s like having air conditioning and heating systems with zero energy consumption – in the summer the home stays cool and in the winter it stays warm.

Breathability

dlt-residentialDifferent layers of different materials with different characteristics can create issues in moisture management.  In terms of building physics, crossed DLT walls consist of just one thick block of layered wood: a wood-only mono-material.  There are therefore no changes in the vapor permeability within the wall and no moisture can condense as they can on vapor-barrier foils or insulation materials often used in conventional construction methods. Wood100ⓇDLT regulates the indoor climate much better because moisture can be transferred freely between the entire wall system.   In our DLT the moisture flow is not blocked by layers of glue which can reduce the breathability of the construction by up to 80%. Such reduced breathability can cause condensation and poor air quality in the build. 

Health

breathability of mass timberWith no off-gassing from glues or contamination from chemicals, Wood100ⓇDLT offers a significantly healthier indoor environment, particularly for those with allergies and hyper-sensitivity. It has been scientifically proven that the heart beats more slowly and you sleep deeper and more soundly in solid wood rooms rather than artificial surroundings. 

The aesthetics of beautiful exposed wood coupled with structural integrity is compelling for architects, builders and home-owners alike. Many studies have documented the health benefits from living, working, recuperating and learning in spaces surrounded by natural solid wood.  Lowered stress levels, better sleep and wellness levels and improved productivity are all reasons for ever increasing use of mass timber in schools, hospitals, offices and homes. 

 

Wood100ⓇDLT can provide you with a healthier space, a more energy efficient space,  a truly sustainable space.  Read more here. With design options limited only by the imagination it’s an architectural dream.  We manufacture and install.  Contact us if you’d like to speak more about Wood100ⓇDLT.