When it comes to commercial and residential buildings, heavy timber architecture has an undeniable appeal. They’re the buildings with massive open spaces and high ceilings sporting beautiful open wooden beams.
But the appeal of heavy timber buildings are more than just aesthetic. Heavy timbers are more durable than traditional stick-built properties and have more character and charm than concrete and steel.
If you’re embarking on your next building project, here’s what you should know about heavy timber construction methods and details.
Building Methods for Heavy Timber Construction
Instead of going to the local lumberyard and picking up a bunch of two-by-four pieces of wood to frame your house, heavy timber construction is a building method that uses larger pieces of wood that are at least six-by-six or bigger, depending on building codes.
The columns and beams can be sawn and cut from a single log or created by putting multiple smaller pieces together using one of three methods:
- Cross laminated timber (CLT): Layers of smaller pieces of wood are glued together with the grain alternating 90-degrees between layers.
- Glue laminated timber (Glulam): Smaller pieces of wood are glued together with the grains aligned in the same direction for additional length.
- Nail laminated timber (NLT): Pieces of wood are fastened together with nails and screws until the beams reach the desired thickness and length.
Unlike stick-built buildings held together with nails and screws, these massive wooden timbers are squared off and fitted using custom-cut joints and large wooden pegs to keep them in place.
Once the pre-cut pieces arrive on site, they’re pieced together. Every beam is specially cut to fit into a specific spot, allowing construction to move much faster with fewer workers.
Heavy timber buildings come with many added benefits, both structural and aesthetic - but they also come with a few challenges that designers and architects need to overcome.
Advantages of Heavy Timber Buildings
There are many benefits that come along with heavy timber architecture. Of course, what most people notice immediately is the unique look it gives a building. In most buildings that use heavy timbers, the timbers remain visible in the rafters, creating a rustic look and feel that many people find welcoming.
Structurally, heavy timber buildings are much stronger and more durable than standard buildings that use dimension lumber, as bigger timbers are sturdier than two-by-fours. They also come with myriad other benefits for both commercial and residential applications, including:
- Fire resistance – Larger timbers don’t catch fire as easily as small boards. Since they’re so thick, it takes much longer for them to ignite.
- Fewer load-bearing walls – Allow more floorplan options and can create larger open spaces for commercial applications.
- Faster build times – Timber frame homes are pre-manufactured and arrive on site ready to piece together. A heavy timber home of average size can be standing within two to three days.
- Environmentally friendly – If harvested responsibly, wood is a renewable resource and doesn’t require the same pollutant-heavy production methods compared to steel or concrete structures. Heavy timber structures are much more environmentally friendly, especially if you use local wood.
- Use less wood – Although the supports might be larger, timber structures use fewer logs compared to stick-built buildings because they can support more weight with fewer beams.
- Less material waste – Precision-cut timbers eliminate excess building materials and reduce waste.
With so many advantages, it’s no wonder that mass timber buildings heavy timber construction methods are becoming increasingly popular for both commercial and residential applications, especially in locations with an abundance of natural wood, like the Pacific Northwest.
Difficulties Associated with Heavy Timber Architecture
While there are certainly some significant benefits to using heavy timbers, there are also a few difficulties:
- Timbers require precision cutting, which requires more time to prepare.
- Heavy equipment is needed to move and fasten the massive logs.
- There’s not much space for mechanical, electrical, or plumbing (MEP) services in the building.
In many heavy timber buildings, the logs are typically left exposed on one side for aesthetic appeal. While the heavy timbers might look nice, it also makes it more difficult to hide important MEP elements like HVAC ducts, electrical wiring, or plumbing.
HVAC systems are particularly difficult to install and are among the most important heavy timber construction details builders need to address.
Air conditioning and heating ducts generally take up a lot of space. Many heavy timber builders simply leave the ducts uncovered in the rafters, but this can be unsightly for many property owners.
Others erect light-frame walls or soffits to hide MEP items, but that hides the beautiful timbers.
One of the best ways to install HVAC into heavy timber buildings is with an underfloor air distribution system (UFAD), which strikes the ideal balance between aesthetics and efficiency.
Use UFAD to Make the Heavy Timber Construction Process Go Smoothly
Installing an underfloor air distribution system doesn’t require the massive ductwork of a traditional HVAC system. Instead, it uses several UFAD diffusers scattered throughout the area, resulting in reduced - if any - ductwork. This equipment is well-sized and can easily fit underneath a raised access floor (hence, “underfloor” air distribution).
Once the construction of your heavy timber building is complete, all you need to do is build a raised access floor to fit the UFAD ducts and diffusers. Your entire HVAC system can be completely hidden without ruining the building’s aesthetic appeal or open floor plan - no need to have unsightly HVAC ducts exposed in plain view.
In addition to making the heavy timber construction process go more smoothly - and making your building look better - UFAD systems offers a range of benefits over traditional HVAC systems, including:
- 30% less energy usage due to efficient air recirculation
- 10-15% reduction in installation time, resulting in quicker tenant occupancy
- Reclaim up to 10% of square footage lost to mechanical spaces
- Decrease build times by 15%
- Increase value of projects by 9.3% or more
- 80% less time to detail in BIM
- Better ventilation by using the laws of thermodynamics to introduce cool air at the floor and remove hot air at the ceiling.
- Flexible wires and pipes for easy relocation
With a UFAD system, you can have all the benefits of a heavy timber building without worrying about where to put the HVAC system. Everything can be easily contained under the floor to make the entire building process faster and more straightforward.
If you’re interested in underfloor air distribution for your commercial or residential property, contact the experts at AirFixture. We’ve installed hundreds of UFAD projects over the past 15 years and will ensure that your next heavy timber building project goes smoothly.
