How do I calculate ceiling joist size and spacing ?
On Oct 2, 6:58 pm, Seņor Chris wrote:
I'm installing an independent ceiling just below the existing one for
sound insulation purposes, so the only load it will carry is an acoustic
quilt above and plasterboard below. Assuming maximum span of 4m and
plasterboard thickness of 25mm, what size joists do I use and at what
spacing ? Is there a generic formula I can use if I vary the span and
plasterboard thickness ?
Done this a number of times before ( its my day job)..... We always
use 6x2 at 600mm centres unless its a really short span of say less
than 1.5m where you might get away with 4x2. Normally we fix a wall
plate using frame fixings, then fix the cross members directly onto
them. Leave about a 50mm gap between bottom of existing cieling and
top of new joist and you should be fine. You don't want any movement
in your secondary ceiling, you don't want to go to all the effort and
then it still fails to pass regs, so we always tend to over spec.
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