Timber Frame Joinery is the method that individual beams are connected together to create the structure of a building. Traditional joinery uses mortices, tenons, dovetails and wooden pegs at each terminating end of a timber to connect to the next adjacent timber. Tenons fit into mortices and dovetails fit into a negative space of the same shape on a beam.

Often timbers, post and beams are held together with steel gusset plates, knife plates or concealed steel connections. Gusset plates create a sandwich on both sides of a timber. Bolts go through the gusset plates and timbers to hold them all together. Knife plates are cut into the center of the timbers with bolts that go through the timber and the knife plate. There are all sorts of concealed steel connections made of rods, lag bolts and plates that enhance traditional joinery when extra strength from snow, wind and seismic loads are high.

Steel joinery is usually stronger in tension, but both steel joinery and traditional joinery are very strong in compression. Often the choice of using steel vs traditional joinery comes down to aesthetics. Some people like the look of steel gusset plates which are reminiscent of old mill buildings while others prefer to the look of  wooden joinery. When steel tension ties are required, but the client doesn’t like the look of steel, the steel can be routed into the timber and hidden. Sometimes of steel and wooden joinery is the perfect look for a building.

Steel gusset plates can be any color. Black is a traditional color, perhaps because it looks a little bit like wrought iron. Galvanized steel is a popular choice and often required if the steel is exposed to the weather. Galvanized or raw steel can be painted any color depending on the client’s choice.