Benefits of 15mm plasterboard?

[MJNewton]

I am putting a new ceiling into our extended 'family room' and was planning on using 15mm plasterboard rather than 12.5mm. The reason being was that I figured it might provides benefits in terms of improved acoustic attenuation for the bedroom above and slightly better fire rating. Perhaps even some benefit regarding stiffness and strength? I've got a plasterboard lifter so the extra weight when installing isn't of concern and I probably only need around a dozen 2.4m x 1.2m sheets so the extra cost should be minimal.

 

However, I didn't realise that 15mm PB doesn't seem to be widely available, even aside from the current supply issues for all gypsum products at the moment, and so I am beginning to have second thoughts if it's not the 'done thing'. Also, where it is sold, it is generally tapered edge and yet I was going to get the whole thing skimmed and so would be wanting square edge. Am I do something odd here?

 

Just wondered if anyone has any thoughts on whether 15mm would provide the assumed benefits, or should I just stick to 12.5mm?

Edited April 30, 2020 by MJNewton

[nod]

7 hours ago, MJNewton said:

I am putting a new ceiling into our extended 'family room' and was planning on using 15mm plasterboard rather than 12.5mm. The reason being was that I figured it might provides benefits in terms of improved acoustic attenuation for the bedroom above and slightly better fire rating. Perhaps even some benefit regarding stiffness and strength? I've got a plasterboard lifter so the extra weight when installing isn't of concern and I probably only need around a dozen 2.4m x 1.2m sheets so the extra cost should be minimal.

 

However, I didn't realise that 15mm PB doesn't seem to be widely available, even aside from the current supply issues for all gypsum products at the moment, and so I am beginning to have second thoughts if it's not the 'done thing'. Also, where it is sold, it is generally tapered edge and yet I was going to get the whole thing skimmed and so would be wanting square edge. Am I do something odd here?

 

Just wondered if anyone has any thoughts on whether 15mm would provide the assumed benefits, or should I just stick to 12.5mm?

12.5 PB are hardly ever used on ceilings in single layer 

One of the main benefits is that you can use I5 mil on 600 centre ceilings without needing to support the edges 

Less cracks on 15 mil boards 

Better for for D&D 

Most builders merchants will stock 15 mil Also 15 mil duplex 

 

[Oz07]

Used 15mm on latest place ceilings. Defintley flexes less on the 600 centres but I always used 12.5 with noggins before and never had a problem. Horses for courses 

[MikeGrahamT21]

Will be a bit more sound insulation too from the 15mm

[MJNewton]

Thanks everyone - maybe it's not so strange a route to take afterall.

 

I do actually have a few joists on 600mm centres (not sure why - I guess it saves on a joist or two in an area that doesn't otherwise need them) and so the 15mm should be better suited (notwithstanding the point about noggins likely sufficing). 

 

On the supply front I must admit to bit having asked the local builder's merchant (they're all closed, I think) and so was only searching online which might not be representative. 

 

I think I'll continue with the plan. 

Edited May 1, 2020 by MJNewton

[Onoff]

Certainly 15mm Sound Bloc (blue) does what it says on the tin. As I got some free (3m boards) I used it on a couple of walls and you can hear zilch from the other side.

 

More meat there too with 15mm when cutting out for downlights, dry lining boxes etc.

[Carrerahill]

10 hours ago, nod said:

12.5 PB are hardly ever used on ceilings in single layer 

One of the main benefits is that you can use I5 mil on 600 centre ceilings without needing to support the edges 

Less cracks on 15 mil boards 

Better for for D&D 

Most builders merchants will stock 15 mil Also 15 mil duplex 

 

Nod, was it you that posted some images of a big dry lining project you had done recently? A big MF and board wall?

[Mr Punter]

1 hour ago, Onoff said:

Certainly 15mm Sound Bloc (blue) does what it says on the tin. As I got some free (3m boards) I used it on a couple of walls and you can hear zilch from the other side.

 

More meat there too with 15mm when cutting out for downlights, dry lining boxes etc.

 

These are really heavy and awkward.  I could not lift one on my own.  We did have a tacker use some but he was young and well built.  2.4m is doable though.

[nod]

39 minutes ago, Mr Punter said:

 

These are really heavy and awkward.  I could not lift one on my own.  We did have a tacker use some but he was young and well built.  2.4m is doable though.

15 mil sound are heavier 

It’s surprising how you get used to handling them I’m 58 and can still fix them to a ceiling on my own if I have to 
20 years back it was always 3/8 boards on the ceilings Now they where a pain on your own

Prone to snapping 

[Onoff]

1 hour ago, Mr Punter said:

 

These are really heavy and awkward.  I could not lift one on my own.  We did have a tacker use some but he was young and well built.  2.4m is doable though.

 

One of the many reasons why my back is like it is. S'funny how I'd always find the strength to lift something if it was free. No change there then. ?

[nod]

18 minutes ago, Onoff said:

 

One of the many reasons why my back is like it is. S'funny how I'd always find the strength to lift something if it was free. No change there then. ?

It is

All the plaster and cement bags where twice as Heavy We used to carry two in when we were loading 

Now I see young lads wondering upstairs with one 25 kg bag on there shoulder 

They think I’m being funny telling them to stick another on there shoulder 

 

A few month back we had 300 

100 mil insulation boards to get from a service lift down some stairs and 20 mtrs along a corridor 

I told all five loaders one each or you won’t get them in today 

about 40 kg but awkward 

Im 58 so I decided to lead by example 

We got them all in 7 hours 

To expensive to leave outside in sunny Burnley 

One of the lads lent me his steps watch 

Quite surprised how many steps in a day 

[Dudda]

If the main goal is to reduce sound then get Gypframe Resilient Bars and fit them to the ceiling first. These are light, easy to fit and readily available. Then fit regular plasterboard to the bars. This will preform much better acoustically than blue acoustic board or thicker boards.

 

However it doesn't matter what type of ceiling you install if you put loads of recessed downlights in the ceiling and make swiss cheese out of it the sound will always travel through the weakest point.

[MJNewton]

1 hour ago, Dudda said:

If the main goal is to reduce sound then get Gypframe Resilient Bars and fit them to the ceiling first. These are light, easy to fit and readily available. Then fit regular plasterboard to the bars. This will preform much better acoustically than blue acoustic board or thicker boards.

 

Hmm.. That was my original plan to be honest but to be honest I got a bit nervous about a method I'd not used before. You think it'd be better then? And by 'regular' boards do you mean 12.5mm?

 

1 hour ago, Dudda said:

However it doesn't matter what type of ceiling you install if you put loads of recessed downlights in the ceiling and make swiss cheese out of it the sound will always travel through the weakest point.

 

There will be five downlights; fireproof fittings though so not completely open like some. Appreciate they will still compromise the acoustic barrier though. 

[Big Jimbo]

6 hours ago, nod said:

It is

All the plaster and cement bags where twice as Heavy We used to carry two in when we were loading 

Now I see young lads wondering upstairs with one 25 kg bag on there shoulder 

They think I’m being funny telling them to stick another on there shoulder 

 

A few month back we had 300 

100 mil insulation boards to get from a service lift down some stairs and 20 mtrs along a corridor 

I told all five loaders one each or you won’t get them in today 

about 40 kg but awkward 

Im 58 so I decided to lead by example 

We got them all in 7 hours 

To expensive to leave outside in sunny Burnley 

One of the lads lent me his steps watch 

Quite surprised how many steps in a day 

Kin hell. i'm going for a lie down just looking at that.