Masonry dimensions

Common masonry dimensions are based on the so-called octametric measurement system, whose basic unit (= standard building measure) of 12.5 cm is the eighth part of a metre. The technical rule for this is DIN 4172 (Measurement Regulations in Building Construction). By dividing the standard building dimension (12.5 cm) into the nominal dimension of the stone length (11.5 cm) and the joint dimension (1 cm), the addition of the shell dimensions of masonry walls results in different nominal dimensions for an

• external dimension (a joint is "missing", so 1 cm must be subtracted from the octametre dimension: e.g. 10.99 m),
• opening dimension (since the opening is measured from stone to stone, 1 cm must be added to the octameter measurement: e.g. 1.01 m or 88.5 cm),
• protrusion dimension (the dimension corresponds to a multiple of the basic octametric unit, e.g. 12.5 cm x 11 = 1.375 m)

A = external dimension = x * 12.5 - 1

Ö = opening dimension = x * 12.5 + 1

V = protrusion dimension = x * 12.5

Although modern masonry blocks, e.g. monolithic exterior walls, are no longer bricked with a 1 cm joint, the masonry dimensions still apply. They should be taken into account as far as possible in implementation plans, as they enable a particularly fast and economical construction site process with a minimum of material waste. The measurement systems of various finishing products are also adapted to the masonry dimensions, e.g. the standard dimensions of interior doors. Dimensional deviations of the shell opening dimensions from the masonry dimensions can therefore lead to additional costs for finishing with elements with special dimensions.

Source: bauwion