A flitch beam (sometimes called a flitched beam) is a composite beam which is made up of a steel plate sandwiched between two timber joists. When existing beams are being strengthened, the timber beam is sandwiched between the steel plates. Sometimes more than one timber joist is used. Because steel is much stronger than timber (around 30 times as strong), the addition of steel plates can strengthen an existing timber beam considerably.

Flitch beams are not as deep as timber beams of the same strength and this can be very useful when space is limited.

The design is based on the proportion of the load which is shared by both the steel plate and the timber, giving the same deflection for both.

Our structural calculations for a flitch beam includes the design of any combination of timber sections and steel plates. Our structural design also includes preparing the calculations for the bolted connections between the steel and timber.

We need the following information to design a flitch beam:

architectural layouts or sketch drawings with dimensions, showing the span of the beam and what the beam will be supporting

the size of the timber beam if it is an existing one (width and depth)

details of the type of construction (concrete or timber floors etc)

details of any other loadings on the beam.

Design information

All design work is carried out in accordance with BS5268 (The structural use of timber) and BS5950 (The structural use of steelwork).

The calculations provided will be suitable for Building Regulation approval.