Heavy timber framing is one of the oldest types of building construction in the U.S., and many of these structures from the past 100+ years are still being used. Originally built for industrial use, heavy timber frame construction can also be found in auditoriums, gymnasiums, churches, supermarkets, schools and other structures, with elements in residential homes. Heavy timber buildings are extremely strong and are recognized in building codes to have excellent fire resistance. They are also architecturally stunning, due to the large exposed wood beams that are the trademark of a heavy timber frame building.
Hamill Creek, expert builders of custom timber frame homes, can create a design for your house that centers around the dramatic beauty of exposed timbers, in the traditional style.
What is Heavy Timber Framing?
The key element of a heavy timber frame is that it uses large stress-graded timbers that are either heavy sawn or glue laminated, connected with traditional mortice and tendon joinery and metal fastenings. Traditionally, cast iron connectors were often used. It is a traditional style of building construction with a history that begins around the 10th century, brought to the U.S. by Europeans in the 17th century.
What was originally accomplished by saws and axes is now made easier and more exact with sophisticated CAD/CAM design and computer numerical control (CDC) technology. This allows for precise cuts, reduced labor costs and increased production, making heavy timber framing more affordable. However, CNC machinery can’t always be used if the timber is too large or the joinery design is too complex. In that case, it is hand hewn, and there remains an artistry to heavy timber frame construction, with a certain amount of hand finishing.
From a design perspective, heavy timber framing, with its large wood beams and columns, lends itself to dramatic wide open spaces with exposed ceiling beams for a warm, rustic appearance. The rising popularity of heavy timber frame homes and other buildings is due to its structural resilience, sustainability and healthy indoor environment.
Heavy timber frame construction has many benefits, such as extreme durability, fast build, greater thermal efficiency than conventional buildings, and a flexible design with less need for load bearing interior walls. Timber frame buildings generate a lower carbon footprint, and there’s less waste in the construction process. Heavy timber frame structures can last for centuries.
What is the Difference Between Mill Construction and Heavy Timber Construction?
Although you may see the two terms interchangeably, mill construction and heavy timber construction as it is known today have important differences.
Merriam-Webster defines mill construction as “wooden building construction designed to procure the greatest possible protection against fire without actual fireproofing by disposing of the timberwork in solid masses without boxed-up hollow places and by supporting the flooring directly on girders and brick walls.” During the industrial revolution in the early 1800s, U.S. mills began to use masonry for the exterior walls of factories, as was done for churches years prior. This became known as mill construction.
Features that are specific to mill construction include:
- Exterior load-bearing walls made from stone or brick
- Beams and columns of heavy timber with cast iron connectors used to cover joints
- Floors of laminated, thick grooved or splined planks
- Roofs made from laminated or thick splined planks were supported by timber arches and trusses or beams
- Openings between floors and building sections, separated by fire barriers
- No concealed spaces (like attics or crawl spaces)
In today’s timber framing, you can combine cozy, traditional rooms with open space designs, and you can benefit from the eco-friendliness and energy efficiency of insulated wall and roof systems.
Heavy timber construction has seen a rise in popularity, to capture the dramatic wide open spaces and exposed beams of the old factory buildings, barns and places of worship. However, it is most often a hybrid design that is used. Heavy timber is used for visible main beams and posts, and timber framing allows for more intricate work and greater design flexibility.
What Types of Wood Products are Used to Frame Heavy Timber Buildings?
Density is the most important quality for framing heavy timber buildings. The denser the wood, the greater its structural strength. Some softwoods, such as Douglas Fir, pine and spruce, are softwood species that are very dense, strong and durable. Other popular wood species used in timber framing include larch and red cedar.
In “Connection Options for Wood-Frame and Heavy Timber Buildings,” the American Wood Council explains that the term “heavy timber” relates to fire resistance. Buildings that meet the requirements of Type IV construction in the International Building Code, which can be both mass timber and timber frame structures, are in this category.
In the mass timber category, other wood products that are used for heavy timber framing include prefabricated wood beams made from a structural composite lumber such as laminated strand, laminated veneer or parallel strand lumber. Cross laminated timber (CLT) is also used.
Hamill Creek Strikes the Perfect Balance of Old and New
For a stunning home or commercial building that celebrates the proud tradition of heavy timber construction with contemporary design, energy efficiency and eco-awareness, speak to the timber frame professionals at Hamill Creek.