What is the difference between timber framing and post and beam? Many people have a hard time distinguishing between the two methods of building with heavy timbers. Primarily the difference is with the connections.
Both timber frame and post and beam construction utilize durable heavy timbers, as opposed to dimensional lumber that can be purchased from any lumber yard. Dimensional lumber has been cut to pre-defined, standard sizes such as 2x4’s, etc. The heavy timbers used in both post and beam and timber frame are much larger and generally remain exposed in the building, creating an honest expression of the structure and giving it a sturdy appearance. When it is designed and constructed with care and skill, the beauty of the frame itself creates the artistic character of the building. The organic beauty of wood is celebrated in the exposed timberwork whether post and beam or timber frame.
Similarities of Post and Beam and Timber Frame
Both timber framing and post and beam are construction methods in which the structural frame is self-supporting and carries the weight of the house. This means that for both methods interior load-bearing walls are unnecessary, which makes possible large open interior spaces and high vaulted ceilings. When the frame is left exposed (as it usually is), an organic beauty enhances the building. Both types of frames are usually prefabricated in a sheltered environment, then labeled and delivered to the job site where they can be quickly raised.
Both timber framing and post and beam are examples of sustainable construction. Quite often the wood in these frames is reused from existing structures, or harvested from standing dead forests. And because of how the timbers are assembled, they can be disassembled and repurposed in a future building.
Differences between Post and Beam and Timber Frame
The main difference between these two systems is the way the timbers are joined. Timber framing dates back to medieval times, and there are structures built then that are still standing today. Timber frames utilize traditional joinery such as mortise and tenons. They incorporate very few metal parts - mainly hidden structural screws where absolutely necessary, such as securing rafters to a ridge. In post and beam buildings the timbers are usually connected with metal fasteners and connectors, which can either be hidden or decorative.
Post and beam usually use half-lap joinery. The fasteners securing the timbers may be hidden within connections or exposed and decorative. Timber Frame uses mortise and tenons, scarf joints, spline joints, and other joinery secured with wooden pegs. The cost of skilled labor to cut and fit the joints is much higher in a timber frame home than a post and beam. However, the metal connectors in a post and beam building can be a significant cost factor.
The raising (erecting) process is different for a timber frame than for a post and beam building. The sections of the timber frame are assembled on the ground and then erected, individually, until the entire framework is completed. With post & beam construction, the frame is built from the ground up, with the parts being added on top of each other.
Timber Framing Characteristics
Post and Beam Characteristics
Advantages of Timber Frame
Disadvantages of Timber Frame
Advantages of Post and Beam
Disadvantages of Timber Frame
Timber framing is a method used by our forefathers and their ancestors, who brought with them the skills used in Europe and other countries for centuries. Using traditional wooden joinery to piece together large, usually squared timbers, the connections are carved out to fit together like a complex puzzle. An example of such a connection is a mortise and tenon joint. When the connection is made, it is usually with wooden pegs because the use of metal is not practiced with timber framing; this type of framing requires a high level of skill and can be very time consuming. There are schools that offer courses to teach these methods such as the the ones found here.
Post and Beam, in contrast to timber framing, has a distinct look that provides a more industrial appeal. This method of framing also uses heavy timbers, however the connections are much less complicated; fasteners in the form of metal screws, bolts and plates are used to connect the timber pieces. The simpler connection usually requires less time to craft. A business like Simpson Strong Tie offers plates and bracing that provide a functional solution in their Architectural Connector product line.
Alternative Framing System: T-Rex Connector
One company to offer an alternative to both framing with mortise and tenon, and framing with angle/corner bracing is Connecticut Post and Beam, with their connector.
This extruded aluminum connector is mostly hidden and no special skills are required. Fine Homebuilding called this method "21st Century Post and Beam,” in a recent article in one of their Spring publications, "Building Sheds". Due to their inquiring customers, Connecticut Post & Beam created a simple connection that balanced the art of timber framing with the industrialization of post and beam. These customers were not interested in spending the time and utilizing the skills needed for traditional methods, nor did they want to use the big metal plates and corner bracing common in post and beam construction. Framing with T-REX presents a viable alternative with a minimal metal look that is not only engineer-approved, but cost effective as well. Plans, connectors and custom tooling are available at Connecticut Post & Beam.
Timber framing and post and beam construction both demand tight, well-crafted joints, but post and beam fabrication is usually less labor-intensive. It is often very hard to distinguish between a timber frame and a well-crafted post and beam structure. The appreciation for traditional craftsmanship versus cost are determining factors in deciding which approach to use. Timber framing can add 25% over the cost of a stick-built home. Timber framing can cost 10-15% more than post and beam construction. Post and beam construction and timber framing both celebrate the beauty of wood, but post and beam breaks from pure traditional joinery.
In conclusion, building with larger timbers encourages personal design choices, showcasing either a handmade and rustic look, or a sleek and more modern appearance.