Centre-to-centre spacing (often abbreviated as c/c) is the distance between the centrelines (centres) of two consecutive building elements, such as beams, trusses, studs or piles. You therefore do not measure the clear space between them, but from the middle of one element to the middle of the next.
This method of dimensioning is used because it is independent of the thickness of the components: whether a beam is 45 or 63 mm wide, the centre-to-centre distance stays the same. This lets you quickly work out quantities and spans.
Application
- Joist layers and floors — floor joists are often spaced 300 to 600 mm centre to centre, depending on span and load
- Framing and timber frame construction — studs are usually spaced 400 or 600 mm centre to centre, matching the sheet sizes of plasterboard and OSB panels
- Roofs — roof trusses and purlins are set at centre-to-centre distances
- Foundations — piles are drawn on a pile plan with centre-to-centre distances
On construction drawings, the dimension is indicated with the symbol “c/c” followed by the distance in millimetres. When ordering material, always allow for one extra component: for a wall of 3600 mm with studs at 600 mm centres you need 7 studs, not 6.
Related terms
- Centre to centre
- Joist layer
- Timber frame construction
- Stud
- Pile plan
- Span
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