Both traditional timber framing and post and beam framing are construction methods that create a self-sustaining frame which carries the weight of a building. Since both systems support the structure’s weight, interior load-bearing walls are unnecessary, which allows for open floor plans and vaulted ceilings. People who choose either method will often leave the frame exposed on the inside, giving the home a natural, rustic beauty.
Joinery Methods
The main difference in the two types of construction is the method of joining the timbers.
Traditional timber framing uses solid timbers connected with traditional joinery and secured with a hardwood peg. The most common type of joint is the mortice and tenon. Woodworkers have used this joint for centuries. It’s made up of a tenon (the protruding part) and a slot (mortice) into which the tenon is inserted and fastened with a hardwood peg. The adjoining pieces connect to create a strong, stable, aesthetically pleasing joint.
Timber frame houses are built by very skilled and highly trained craftsmen. Fitting the joints correctly requires great precision and care.
Post-and-beam construction, on the other hand, uses butt joints and half-lap joints connected with screws, bolts, and/or metal plates. This method results in a very different look, and the joints are often less tight than in a traditional frame because the strength relies on the engineering of the metal plates rather than the craftsman’s skill.
Materials
Traditional timber-framed houses are made of solid wood. The most common timber species used in Ontario are white pine, white cedar, with cherry, oak, and ash for curved accent pieces. Builders may also use Douglas fir, shipped in from the West Coast. Pegs can be white oak, cherry, maple, or walnut for a stunning natural colour contrast.
Post and beam constructions may use solid wood as well, but they often use engineered wood known as glulams (glued, laminated timber), and of course they have the previously-mentioned metal connectors. Western red cedar, Alaskan yellow cedar, Douglas fir, larch, pine, spruce, hemlock, and California redwood are the most frequently-used woods for post and beam applications.
Finishes
In a traditional timber frame, timbers can be left rough-sawn, which is a good option for exterior work, but they would collect too much dust if used inside. Alternately, they can be planed smooth (which is the most common interior finish), adzed, or even broad-axed for a hand-hewn look.
If you leave the timber raw, it will get dirty quickly and direct sunlight will cause the wood to go grey. Natural oil is a common way to finish a timber frame if you want a very natural look, or it can be stained to give it a bit of colour and UV protection.
Consider Using Traditional, Solid Wood Timber Frames to Avoid Large Chunks
The main drawback of using the post and beam method in the construction of your custom timber frame home is that it introduces large chunks of metal into solid wood, which promotes condensation. Additionally, post and beam frames don’t settle the same way traditional timber frames do. Traditional joints get tighter and stronger as the timbers dry out in place, but post and beam joints may actually get weaker because the wood shrinks and twists as it dries but the metal fasteners don’t adjust to the new size and shape.
