Many people know what posts and beams are, but fewer understand what post-and-beam construction is and how it is different from timber framing. These two methods both use heavy timber, but the joinery is different.
Post-and-beam construction has been around for centuries and can be traced back to 2000 B.C. Post-and-beam buildings from the 18th and 19th centuries still standing today are a big testament to the durability of this construction method. This article will distinguish between post-and-beam and timber framing in construction.
Table of Contents
What is post-and-beam?
Post and beam construction is a method of construction that utilizes large, widely-spaced wood to provide structural support to the building. The wood is used to create a frame that walls are then placed into. Post and beam construction is mainly used in open-plan homes because the beams carry the roof’s load and reduce the need for interior walls. Â
In this construction method, the posts and beams provide vertical support to the structure. Diagonal shafts may be used to carry lateral loads. We may use post-and-beam frames with sheer panels to enhance structural support.
Posts and beams also carry cladding and finish for interior and exterior walls. Additionally, posts and beams provide insulation to a building.
Engineers design post-and-beam frames to be ornamental and structural. We can use metal connectors, but these can be exposed to add to the aesthetics or completely hidden.
Post-and-beam structures may cost less than timber frame structures because the joinery is not as complex, and labor costs could be lower.
The designer of a post-and-beam project typically has a lot of creative freedom to develop spaces because this method is flexible.
The origins of post-and-beam
Posts and beams are a part of contemporary homes as modern architecture has found a place for these elements in residential and commercial buildings. However, posts and beams are not a new invention and have been around for a long, long time.
Post and beam construction can be traced back to 2000 B.C. in Europe. Today, there are still some post-and-beam constructions from the Middle Ages that have stood the test of time.
During the 1600s, posts and beams were traditionally used for columns, beams, girders, purlins, rafters, roofs, and floors. Hand-hewn pieces of timber were joined by joint geometry or using hardwood pegs.
This method was also widely used in North America during the 18th and 19th Century, and several buildings from this era are still standing. Posts and beams are made into a robust structure using mortice-and-tendon joints. Post-and-construction may have evolved, but it is not a new concept.
Traditional timber-frame construction, on the hand, typically uses cheaper wooden panels that carry the load of the roof and create an extraordinary boundary between the interior and exterior walls of the property.
Post-and-beam vs. timber frame
The terms `timber framing’ and `post and beam construction’ are often used interchangeably, but these terms do not mean the same thing. There are some similarities between the two construction methods; post and beam remain utterly different from timber framing.
Timber framing and post-and-beam construction provide any building with sufficient structural support to carry loads of the house. Therefore, the two methods are ideal for executing projects with high vaulted ceilings and large interior spaces, thereby making interior load-bearing walls unnecessary.
Both post-and-beam construction and timber framing have great aesthetic value, especially when left exposed. The two types of frames are prefabricated off-site in a sheltered environment before being labeled and delivered to the construction site for quick installation.
Post-and-beam construction is just as sustainable as timber framing. The wood used in the two types of construction is usually either harvested from standing dead forests or reused. The timber is assembled in a manner that accommodates the repurposing of the building. The wood can be assembled and disassembled for use in another project.
Timber framing uses complex traditional joinery, which can be hard to execute. Timber framing is done using mortise and tenons. This conventional joinery method may incorporate a few metal parts which could transform the entire building.
On the other hand, in post-and-beam construction, the heavy timbers are connected using metal connectors and fasteners. These metal connectors serve a structural purpose in a building, but they can also be left exposed to enhance the beauty of the building.
The other difference between the two systems lies in raising or erecting. In post-and-beam construction, the frame is built from the ground up, and other parts are added. On the other hand, timber framing involves assembling the sections of the frame based on raising them individually to create the completed structure.
Timber framing may be more costly than post-and-beam construction because specific expertise is needed to cut and fit the joints requires particular knowledge and skill.
Advantages and disadvantages of post-and-beam
Below are the advantages and disadvantages of post-and-beam construction.
Advantages of post-and-beam
- Sustainability: Post and beam homes offer sustainability because of bio-degradable materials. Secondly, post-and-beam construction utilizes raw fire-resistant materials such as oak and pine.
- Fire resistance: Oak can withstand fire longer than even steel. Oak is also known to look better with age and has a lifespan of approximately 300 years.
- Durability: Types of wood such as pine are heat-treated to meet EU regulations against pest infestation, making post-and-beam construction even more long-lasting.
- Aesthetically pleasing: Posts-and-beam construction is aesthetically pleasing because it delivers a dramatic and spacious design when done correctly. The post-and-beam system can be as ornamental as structural because the metal connectors can be left exposed as decoration.
Disadvantages of post-and-beam
- Expensive: One of the significant drawbacks of post-and-beam construction is the high costs. Posts and beams may cost up to 25% more than timber frames for the same building. This cost is due to the extra labor required for post-and-beam construction.
- Time-consuming: Post-and-beam construction is a time-consuming process. It may be a real nuisance, especially during lousy weather.
- Susceptible to destruction by moisture: The post-and-beam system is also susceptible to moisture due to the steel surfaces, which may rust and rot the surrounding wood.
Advantages and disadvantages of timber frame
Below are the advantages and disadvantages of timber frame construction.
Advantages of Timber Frame
The wood-to-wood joinery used in timber framing can last for generations if well maintained. Timber framing also tends to be more artistic and elegant than post-and-beam. Finally, traditional wood joinery used in timber framing is flexible and allows for movement with little risk of collapsing.
Disadvantages of Timber Frame
- It needs a lot of skill to execute: The main disadvantage of timber framing is that it requires a lot of skill, leading to high labor costs.
- Too lightweight: Some users say that timber frame construction does not feel as solid as traditional construction.
- Sound transmission: Timber frames do not transmit sound well, unlike other construction materials.
Summary
Post-and-beam construction is very similar to timber framing because both methods use heavy timber. However, the critical difference between these two methods lies in the joinery. Post-and-beam construction can be traced to 2000 BC and is a craft that has been perfected over centuries.
Post-and-beam construction is an excellent method because it delivers ornamental and dramatic buildings and can withstand the test of time. Some post-and-beam buildings constructed in the 18th and 19th centuries are still today. Understanding these two systems when working with wood is critical before settling on one for your next project.
