So, I need to put a false ceiling up in the celler to provide sound poofing and to tidy the place up..
My question is, can I just use MDF or does it have to be fire proof?
I want to board out in between the joists.
Cheers..

what could possibly go wrong…….

🙂

No, dont use mdf.
Sound rated plasterboard, with insulation between the joists to a bit below the joists woudl be good so the noise doesnt transfer so easily from ceiling to joist to floor above.

http://www.wickes.co.uk/Knauf-Sound-Panel-Tapered-Edge-2400x1200x12-5mm/p/224657

that stuff will weigh a ton!

what you mean by a false ceiling – if you mean boarding over the bottom of those joists that is actually a ceiling!

a false ceiling would lower the head height further

I’d just board over with standard 12.5 plain edge, and use insulation in appropriate places – ie avoid wiring etc

If you want good soundproofing do 2 layers of plasterboard, however you must be aware of the weight you are placing on the joists

i read it that he wants to leave the joists on show and board between.

i wouldnt be using MDF either.

i read it that he wants to leave the joists on show and board between.

i wouldnt be using MDF either.

This…

So, what should I use then trail_rat?

id probably fix battons on the inner faces of the joists and hang standard 12mm plaster board off – perhaps with some light weight insulation behind for increased sound proofing

Why do you want the joists on show though ? they dont look particularly nice for a feature.

100 times less work just to board it on the bottom face.

Only reason is it’s not that high, and if I bordered over them, it would feel even lower…
Just trying to create the illusion of height..
It’s going to be my bike store, so not gonna be ‘that’ fussed about it not looking pretty.

PB is 12.5 thickness 25mm if you double board for fire proofing. Would you notice this?

Bloody hell Nick, you’ll be retired before you finish that if you try to board between the joists. Especially buggering about with all that (currently) exposed wiring. If you want an illusion of height, then board it on the joist bottoms and get someone to paint a picture of a nice blue sky on it!!

Teetosugars, two layers of plasterboard is often used as “fireproofing” and will give a considerable amount of soundproofing on its own.

The bottom line really is with you deciding how “posh” you want the result to be ?

If it’s just a “bike fettlery” and you want to “pump out some choonz” whilst you avoid gardening/housework. Then slap on one layer of 12mm Plasterboard BUT mark the joist centres across the boards/on the walls.

Then, if the sound proofing isn’t what you’d hoped you can stick another layer on at 90degrees.

If you want a proper posh downstairs Den, then tidy up the wiring to maximise the space and follow Trail Rats’ advice by battening out, cutting the plasterboard and slinging in ordinary insulation (wear gloves ‘cos that stuff can be a royal PITA).

Budget job = done in a couple of hours
Posh Den = weekender

Board over it ( 12.5mm pb ) and put insulation between the joists. Id use a mineral wool though as opposed to a Celotex type. Wool type also comes in different densities for varying levels of sound-proofing. You can get a sound-block pb but very heavy. Paint the pb a bright white ( you can get a Dulux light and space paint with better reflective qualities but might be a bit overkill for a cellar )…painting a light colour will give the illusion of more space than dark exposed beams..

Secret here is lots of light/ brightness. ..

Cheers all, gonna board over them.
Save all the dicking around.
Just need to leave a gap so I can bung hooks into the joists to hang bikes from.

just make sure the joints are marked and screw through plasterboard to hit wood. why leave a gap?

The gap would be to enable me to screw a hook into the joist.
Unless I just cut a hole in after?

Teetosugars, just mark the postion of the chosen joists on the plasterboard, then drill pilot holes where you need them through the plasterboard and the hooks will be secured into the joists. That will also help you avoid hitting any of the cabling or plumbing and the ensuing “blackout and water feature comedy”.

If you need to secure something between joist for any reason then do as Trail Rat suggested and fit a couple of battens to the joists, allowing enough depth to then fit a “patress” of ply (suggest 18mm offcut) across the battens.

Then the patress will lie flush to the upper surface of the plasterboard and will accept fixings from below.

And BTW
“Builderstrackworld™”, surely that should read “BuildersCrackworld™” ??

Id use a mineral wool though as opposed to a Celotex type. Wool type also comes in different densities for varying levels of sound-proofing.

‘earth wool’ is nice and dense and sound-proofy. Its made from recycled glass bottles and is a bit scratchy to handle but not as maddenly itchy as yellow mineral wool. You can get it in pre-cut ‘batts’ rather than on a roll – if the batts match the spacing of your joists (it comes in 40cm and 60cm widths) then you can just push them between the joists and they stay put so much less handling.cutting and less scratchiness. You can usually get it in B&Q.