Flitch beam wooden beams, and have been largely supplanted by more recent technology. “Flitch” originally referred to a slab of bacon, which was cut into strips lengthwise. Similarly, a wooden beam was flitched by cutting it lengthwise; one half was then rotated 180 degrees both longitudinally and laterally to ensure that any defects were separated. In the 18 century, before the availability of steel beams, pine beams were flitched with hardwood such as oak. With the availability of affordable steel, flitch beams became a way to strengthen long-span wooden beams cost-effectively while taking up less space than solid wood. An 1883 article
Flitch beam construction. Glulam beams were used to support the second floor and the roof. This allowed the appearance of wooden columns, while providing the necessary strength. The method for calculating the size of a flitch beam to be used in construction is straightforward, using the transformed-section method. The steel piece of the beams is imagined to be an equivalently flexible (although much thicker) piece of wood. This allows the elasticity of the entire beam to be calculated as if it were entirely made up of wood. There is modest business activity involving flitch beams with The Timber Research and Development Association