Three of the most common materials in construction are heavy timber, steel, and dimensional lumber. Each one comes with advantages and disadvantages, but heavy timber offers some impressive benefits that set it apart. Let’s take a look at some of the characteristics of heavy timber and see how steel and dimensional lumber compare.
1. Visual Appeal & Biophilia
Because of their natural beauty and warm aesthetic, heavy timber beams are often left exposed in buildings. This creates a very distinctive look, but also has positive effects on people’s mood, stress levels, and productivity. This is because of biophilia, humans’ affinity for nature.
The industrial look of steel doesn’t promote the same biophilic benefits or warmth. And while dimensional lumber is also made from wood, it doesn’t offer the same aesthetic as heavy timber and is typically covered in the construction process.
2. Fire Resistance
It may surprise you that heavy timber offers excellent fire resistance. The surface of timber beams char when exposed to fire, which protects the inner wood and maintains their structural integrity.
Lumber, however, is combustible and does not offer the same levels of fire resistance. As you might suspect, steel is fire-resistant. Depending on its alloy, it will begin to soften around 1000 degrees Fahrenheit, and melt around 2500, which can be catastrophic to the structure.
3. Sustainability & Eco-Friendliness
Because wood is a renewable resource, captures and stores carbon dioxide from the atmosphere, and leaves less of a carbon footprint when compared to steel, heavy timber and dimensional lumber are the most eco-friendly choices of these three building materials.
Heavy timber has a slight edge over dimensional lumber thanks to its lower embodied carbon level. Embodied carbon is the amount of greenhouse gases resulting from the extraction, processing, manufacturing, transport, construction, use, and disposal of a material. Dimensional lumber’s embodied carbon is higher than heavy timber’s due in part to it requiring more processing.
Steel has a much higher level of embodied carbon than either wood product, and it also creates buildings that are less energy efficient. Because it conducts heat more readily than other materials, steel requires more insulation and more energy usage to maintain comfortable temperatures within a building. Emissions from this energy usage, on top of steel’s embodied carbon, gives it the largest carbon footprint of these materials.
4. Thermal Insulation
Timber’s cellular structure has air pockets that create a natural barrier against heat and cold. Additionally, heavy timber and dimensional lumber don’t conduct heat and cold to the surrounding insulation as much as steel. These attributes help to reduce the amount of energy needed to heat and cool buildings built with timber and lumber.
5. Structural Performance
Heavy timber is extremely strong and durable, so it provides excellent structural stability. For example, this timber frame pavilion in Florida was able to withstand the intense winds of Category 4 Hurricane Ian in the fall of 2022, while many structures in the area were completely destroyed.
Steel is also a high-strength material that stands up well to high winds and earthquakes. The structural performance of dimensional lumber in hurricanes and earthquakes, however, varies considerably, depending on the quality of construction and adherence to building codes.
6. Construction Efficiency
A perk that all three materials boast is that project components can be prefabricated in an off-site facility, then assembled on location at just the right time. Fabrication can be done while the job site is still being prepared, which can shorten a project’s overall timeline and bring a faster ROI. (To learn about this and other benefits of off-site timber frame construction, check out our blog post here.)
If off-site construction is your main priority, you might prefer heavy timber for all of the reasons listed above, but also because it can be more manageable to transport and unload than steel or dimensional lumber. Because of its inherent larger dimensions, your project might require fewer individual pieces of heavy timber than if you were using dimensional lumber. Heavy timber components are also likely to be lighter than those made from steel.
Heavy Timber Makes the Grade
Ultimately, the best building material for your project will depend on a variety of factors, including your budget, location, and design aesthetic. But heavy timber’s visual appeal, performance, and sustainability and efficiency benefits make it an ideal choice for just about any type of structure you’re building.
At Mid-Atlantic Timberframes, we’re constantly striving to advance the art of timber construction, and we’re eager to share our expertise. To learn more about why heavy timber might be right for your project, contact us today, or check out our project gallery for inspiration.