I have decided to install a lowered ceiling in my kitchen, partly to avoid having to repair it considerably, partly to install downlighters, but mainly to hide the ducting for the cooker hood which is 6" flexible aluminium tubing.
My question is what size wood to use for the joists which will cover a span of approx 2.5m. If necessary I could support the joists along the middle by a batten fixing to the existing ceiling. If I were to use 9.5mm plasterboard can I get away with less substantial joists than using 12mm.
-- Chris Melluish