What are knee braces?
These are the usually smaller diagonal timbers that typically connect a timber post to a beam above. The brace has a tenon on both ends that fits into a corresponding mortise in the post and the beam, where it is pegged in place. Generally, the braces are straight or gently curved, the latter being a style element taken from shipbuilding where a large curved brace afforded more room in the ship’s hold. The braces serve to strengthen the timber frame by resisting “racking” (an engineering term for leaning or tilting when a force is exerted against the structure) and by carrying the load from the beam above to the post below.
