Dropping ceiling heights

[Markusbydark]

Sorry if this is something that comes up a lot..... However I'm struggling to find a correct answer.

I'm looking to drop our ceiling height by 40-50cm by fitting a wooden frame and boarding. I looked into the metal frames but costs were fairly high and I'm happy enough to use wood.
My question is in a room with a maximum length of 4 meters what size timber do I use? I have found regs but they are for floor joists. This suggests 7x3 at 600mm spacing. This (which I could be wrong) seems slightly overkill to take the load of the boards.

Any help would be massively appreciated,

Mark

 

[Jackrae]

3x2 more than adequate if you fix hangers into the joists above. Thin metal straps screwed into the joists through the existing ceiling at say 500mm centres and then screwed to your new 3x2 joists will be more than adequate to support your new ceiling. If possible run your new joists at right angles to the existing joists as this'll make hanger positioning much easier.

I did my ceiling using this method about 20 years ago and it's still perfect.

 

[foxhole]

If you want to drop 50cm [why?] secure to existing ceiling at 90 degrees to current timbers. I would set at 450 or 600 centers depending on the plasterboard sizes used.

 

[Jackrae]

50cm not 50mm - factor of 10 difference