Kitchen ceiling reboarding- board weight vs joists

[drives]

Hi all,

I'm reboarding my kitchen ceiling at the moment and just wanted to check on the below before proceeding further.

Firstly, the existing ceiling was double plasterboarded. The reasons for taking it down was due to part of it sagging as a result of a previous leak (self inflicted- accidentally drilled through CH pipe from above), and a lot of rewiring required.

I thought I may as well go for a double layer of acoustic plasterboard as we have a bedroom above. I did check the weight specs and it is 2.5kg more per sq m (10.5kg per sq m versus 8kg per sq m for standard). thus in the grand scheme of things I thought negligible. I am however now doubting myself. Floor joists above are 200mm by 47mm. I can find a lot of guidance regarding what weight from above but am struggling a bit to find anything regarding what you can hang off it below. It will obviously be evenly distributed across a 4x4m room.

 

[aveatry]

Double layer of acoustic
That is going to be very heavy. Do you have a board lifter. Using acoustic on its own on the ceiling will do nothing for the sound in the bedroom above

 

[aveatry]

To reduce noise you may be better off with normal boards and rock wool sound slabs

 

[drives]

Double layer of acoustic
That is going to be very heavy. Do you have a board lifter. Using acoustic on its own on the ceiling will do nothing for the sound in the bedroom above

Thanks yes I do have a board lifter.

I'm thinking that you are right and I have made an error. Perhaps the layer of the acoustic and then regular 9.5mm on top? I am using some rockwool as well.

I was looking at the specs and thinking the difference as said was not that much but looking again at some of the existing double boarded ceiling this is a layer of 12.5 and then a layer of 9.5.

 

[aveatry]

Wondering why it's double boarded in the first place, is there steel that needs fire protection or was it previously over boarded to cover up an ugly ceiling.

 

[aveatry]

Just use 12.5 one layer of standard and rock wool acoustic as double boarding will have almost no effect on soundproofing unless accompanied with a whole lot of other sound proofing products, decoupling ect.

 

[drives]

Just use 12.5 one layer of standard and rock wool acoustic as double boarding will have almost no effect on soundproofing unless accompanied with a whole lot of other sound proofing products, decoupling ect.

Thanks. Again fair point. It was one of those ones where the price difference versus normal boards wasn’t that much.

The double boarding is as much to achieve the same ceiling depth as the adjacent lounge (which I’ve now knocked through to) to be honest.

I should add I’ve already got the acoustic board…

 

[aveatry]

Not an expert but I have soundproofed a wall battens decoupled from fixing points with decoupling rubber, rockwool in-between and 2 layers of acoustic board separated from each other with a product called green glue. It was a major undertaking, I can see how a ceiling would be done

 

[freddiemercurystwin]

Or go with one layer of 12mm acoustic on resilient bars, though that may be too deep overall.

 

[aveatry]

resilient bars, though that may be too deep overall.

They are the type of thing I was thinking of. To get any meaningful sound reduction you have to go "all in" with everything, double acoustic, de coupling, resilient bars, acoustic rockwool, shortcut on any one element and you have wasted your time and money on the rest.
That is my understanding from the research I did before I soundproofed a wall

 

[aveatry]

As it's only to bring the levels the same how about fixing 9.5mm strips of ply to the joists and then 1 layer of 12.5 board

 

[drives]

Thanks all. I have done a fair bit of research as well (previous house was very close to motorway- too close as it transpired, so we moved to a complete doer-upper!).

The rationale for acoustic was I needed to reboard anyway, it was only a few pounds more than regular. I did have a look/think before buying it all, and it was an extra 2.5kg per board, per sq metre.

However, I will do the second layer in 9.5 reg. Granted I have wasted a bit of money, which is slightly annoying. I do need to get it level with the board in the living room though otherwise the transition will be tricky.

 

[drives]

As it's only to bring the levels the same how about fixing 9.5mm strips of ply to the joists and then 1 layer of 12.5 board

Wish I thought of that before I started. I’ve started putting up a few of the acoustic boards so probably more work to take them down now and instigate that plan

 

[aveatry]

That extra weight may not sound much but that board is flipping heavy. So you already have the acoustic board?

 

[aveatry]

Wish I thought of that before I started. I’ve started putting up a few of the acoustic boards so probably more work to take them down now and instigate that plan

You could stop and carry on with the strips form now