Understanding (hopefully) plasterboard options for ceiling

[MortarThePoint]

I thought I would record some of my research into plasterboard options and hopefully people can share their thoughts.

 

Each manufacturer has their own equivalents, but I'll consider British Gypsum for ease. They have a useful selector here.

 

Wallboard: 9.5/12.5/15 mm with area densities of 6.3/8.0/9.8 kg/m2. Available TE and SE. Thicker boards available as 900x2400, all available 900x1800. 12.5mm available 1200x3600!!

Wallboard TEN: 12.5mm, 10kg/m2, TE only.

SoundBloc: 12.5/15 mm, 10.6/12.6 kg/m2. Only TE. Minimum 1200x2400. "higher density core". Moisture resistant option (SoundBloc MR).

SoundBloc F: 15mm, 14.1kg/m2, TE min., 1200x2400. " higher density noise insulating and fire performance core"

F MultiBoard: 6/10/12.5 mm, 6.0/8.5/10.6 kg/m2. Only SE. Minimum 1200x2400. Fire and impact resistant.

FireLine: 12.5/15 mm, 9.8/11.7 kg/m2. SE and TE. Minimum 900x1800. Fire resistant, moisture resistant option (FireLine MR) also available.

Moisture Resistant: 12.5/15 mm, 8.6/10.1 kg/m2. SE only available 12.5mm 1200x2400, otherwise TE. "water repellent additives in the core", kitchens and bathrooms.

DuraLine: Not Available.

 

Highest 'area density' is 15mm SoundBloc F (14.1kg/m2).

15mm SoundBloc is around £12.30/sheet. Same supplier sells 12.5mm WallBoard for £6.77/sheet. 12.5mm Moisture Resistant is £10.90/sheet. 12.5mm FireBoard is £8.50/sheet.

 

Solo installation and handling of 2 layers of 12.5mm WallBoard may be easier than 1 layer of SoundBloc and have a 27% higher 'area density' for 10% higher cost. I can't readily find costs for 9.5mm Wallboard, but two layers of that would have the same 'area density' as SoundBloc and be much lighter to handle. 12.5mm layers of Wallboard and Fireboard combine to make an 'area density' of 17.8kg/m2 which is 41% higher than SoundBloc for 24% higher cost.

[MortarThePoint]

Condell:

• 15mm SoundBloc £12.32/sheet
• 15mm SoundBloc F £12.94/sheet
• 12.5mm WallBoard TEN £8.32/sheet
• 12.5mm WallBoard £6.16/sheet
• 12.5mm FireLine £8.94/sheet
• 9.5mm WallBoard £6.25/sheet

No brainer to step up from SoundBloc to SoundBloc F (+5%) if you are interested in sound or fire. It would be harder work to fit though.

2 layers of 9.5mm or 12.5mm WallBoard are cost comparable with SoundBloc with same or higher 'area density' and lighter but longer installation and more screws.

[MortarThePoint]

900x1800 sheets of WallBoard (9.5mm or 12.5mm) or Fireline are £3.99/£5.80 which works out as 56% of the area for 65% of the cost. Easy handling, more screws and more joins.

Edited May 8, 2021 by MortarThePoint

[tonyshouse]

15mm on ceiling never use 9.5 walls should not have plasterboard on them - use masonry and wet plaster 

[Thorfun]

this is a really noddy question but one I've just never known the answer to.....why would you choose tapered edge over square edge or vice-versa? why are there 2 types of plasterboard edging? what use case is there for each edging type?

 

ps. not read through the plastering forum so if this has been answered there many times I apologise in advance

Edited May 8, 2021 by Thorfun

[Tennentslager]

tapered edge allows mesh tape plastered in to make the join

Edited May 8, 2021 by Tennentslager

[dangti6]

8 minutes ago, Thorfun said:

this is a really noddy question but one I've just never known the answer to.....why would you choose tapered edge over square edge or vice-versa? why are there 2 types of plasterboard edging? what use case is there for each edging type?

 

ps. not read through the plastering forum so if this has been answered there many times I apologise in advance

Taper edge is primarily used for taping and jointing - essentially filling the tapers with compound and sanding opposed to skimming the whole wall.

 

Straight edged is just that, straight at all 4 edges. This can still be taped and jointed with compound though.

 

 

[Thorfun]

Just now, dangti6 said:

Taper edge is primarily used for taping and jointing - essentially filling the tapers with compound and sanding opposed to skimming the whole wall.

 

Straight edged is just that, straight at all 4 edges. This can still be taped and jointed with compound though.

 

 

so if you're having your walls plastered then it's straight edge all the way? I assume there's a price difference between the two as well?

[MortarThePoint]

No price difference in the boards really. Tapered edge is all about taping, filling and sanding the joints whereas square edge would get skimmed all over

Edited May 8, 2021 by MortarThePoint

[MortarThePoint]

This is a useful resource that I have just found: Stockist Guide - Construction details.

 

 

It shows other makeups for ceilings and floors. Some of the other ceilings are surprising less performant than one might expect.

[tonyshouse]

The butt ends aren’t tapered - so may as well use square edge as problem is the same then 

[MortarThePoint]

11 minutes ago, tonyshouse said:

The butt ends aren’t tapered - so may as well use square edge as problem is the same then 

 

Is that the 4' sizes aren't tapered, just the 8' sides? I guess it's mainly for walls then

[PeterW]

4 hours ago, MortarThePoint said:

Solo installation and handling of 2 layers of 12.5mm WallBoard may be easier than 1 layer of SoundBloc and have a 27% higher 'area density' for 10% higher cost.

You can’t solo a standard board unless you have a lifter and someone helping you load them - they are too unwieldy and you’ll just end up snapping them. 
 

What’s the purpose of increased thickness ..? If it’s sound reduction then look at resilient bars. 

[MortarThePoint]

1 minute ago, PeterW said:

You can’t solo a standard board unless you have a lifter and someone helping you load them - they are too unwieldy and you’ll just end up snapping them. 

 

It's not fun, but done it before. A dead man or lifter makes it possible. Much better and more fun with a helper though.

 

3 minutes ago, PeterW said:

What’s the purpose of increased thickness ..? If it’s sound reduction then look at resilient bars. 

 

Mass. Resilient Bar still needs to work in unison with an isolated mass.

[MortarThePoint]

The more exotic moisture resistant plasterboard is hard to get hold of at the moment (e.g. FireLine MR, SoundBloc MR, Duraline MR).

 

Is there a way of wet plastering a non moisture resistant plasterboard and making it moisture resistant?

 

Alternatively, can you stack a sheet of standard MR under a standard FireLine and effectively have it moisture resistant?

[Pocster]

On 08/05/2021 at 22:02, PeterW said:

You can’t solo a standard board unless you have a lifter and someone helping you load them - they are too unwieldy and you’ll just end up snapping them.

You can !

But it’s not much fun 

[Oz07]

Just tank the walls after standard wallboard has been skimmed. Did away with mr long time ago

[MortarThePoint]

1 hour ago, Oz07 said:

Just tank the walls after standard wallboard has been skimmed. Did away with mr long time ago

 

It's ceilings I'm particularly interested in. Some of it is for a garage with home office above. Regs say I have to have fire rated, but being a garage I want moisture resistant. I'll be using SoundBloc in house too and then have bathroom so want moisture resistance there

Edited June 14, 2021 by MortarThePoint

[recoveringbuilder]

14 minutes ago, MortarThePoint said:

 

It's ceilings I'm particularly interested in. Some of it is for a garage with home office above. Regs say I have to have fire rated, but being a garage I want moisture resistant. I'll be using SoundBloc in house too and then have bathroom so want moisture resistance there

As a matter of interest will you have to double sheet your garage ceiling? Just thinking back to when we built our last house it had a studio above the garage and we had to double sheet the garage ceiling.

[Oz07]

Loads of garages just use fireline it must be up to the job. 

[MortarThePoint]

8 hours ago, recoveringbuilder said:

As a matter of interest will you have to double sheet your garage ceiling? Just thinking back to when we built our last house it had a studio above the garage and we had to double sheet the garage ceiling.

BCO said he's wanting 30 minute fire rating so 15mm of fireline OK. He asked if it was going to be skimmed and I said it was, so that may be significant. If using 12.5 sheets I'd may have to double up.

[joe90]

I always thought 12.5mm plasterboard (skimmed) was 30min fire rated ?

[MortarThePoint]

21 minutes ago, joe90 said:

I always thought 12.5mm plasterboard (skimmed) was 30min fire rated ?

 

Looking at the White Book C06 S06, it seems it can depend if you are trying to achieve BS EN1365-2 or BS 476: Part 21: 1987. No mention of skim. If I read it correctly, 600mm centres requires 1x15mm WallBoard or better.

 

A skimmed 12.5mm sheet feels like it should be as good/thick as a 15mm sheet, but I don't see it sanctioned anywhere. Your BCO may accept it, I don't know.

[MortarThePoint]

I was planning to use a single layer of 15mm SoundBloc F mounted @ ~450mm centres in resilient bar for the ceiling. Due to availability I am wondering about changing that to 2 layers of 12.5mm WallBoard mounted @ ~450mm centres in resilient bar. The mass will actually go up from 14.1kg/m2 to 16kg/m2. Both options would be skimmed. Price is about the same and I expect the fire resistance of two layers of 12.5mm WallBoard would be as good as one 15mm layer of SoundBloc F.

 

Any thoughts?

[dpmiller]

have you checked for "other brand" options or just BG?