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Plastering

9.5 or 11.5mm plasterboard for new ceiling

Replacing old ceiling made of lath & plaster, replace it with plasterboards and then skimm over it, for both upstairs and downstairs ceilings.

Now which depth should I get, some suggest 9.5mm as they're mainly used for ceiling and the larger verison for walls, but then again others say 11.5 is now often used.

Sorry, should have wrote 12.5mm not 11.5mm!

8 Answers from MyBuilder Plasterers

Best Answer

I would always use 12.5mm plasterboars, (using dry wall screw to fix the boards and not nails) because it they are more rigied if the lath a plaster becomes loose, and also you get better fire protection fron 12.5mm plasterboards. use 1800/900 size boards due to the size difference, you would struggle lifting the 2400/1200 boards using two people

2012-07-22T20:20:02+01:00

Answered 22nd Jul 2012

If your overboarding lath and plaster then the joist centres are likekly to be 16"(400mm) if you were boarding in a modern house with trussed roof the the centres would be 600mm. Generally I would use 9mm for a 400mm centre but 12mm for a 600mm centre as it is less likely to sag between centres over time.

2012-07-22T20:20:02+01:00

Answered 22nd Jul 2012

If you are going over existing L@P 9.5 is ok
If you are removing L@P ,because the depth of new plasterboard+ skim coat of plaster is not as deep as L@P you end up with the top of the wall damaged.
To get over this,if you strip the joist out with Plasterboard then fit 12.5[dont think there is a 11.5] that should bring your ceiling to the same depth as the L@P without any damage showing to the top of the wall...Richard

2012-07-22T20:20:02+01:00

Answered 22nd Jul 2012

Full marks to coastal.As you say you are REPLACING not overboarding,the tops of your walls will be the biggest issue.Hes even told you how to get over it :)

2012-07-23T09:45:02+01:00

Answered 23rd Jul 2012

that would depend who is fitting them, the thicker ones are heavier, regardsTerry.

2012-07-22T20:20:02+01:00

Answered 22nd Jul 2012

They are phasing out 9.5mm boards however generally 9.5mm is used for ceilings and 12.5mm for walls.

2012-07-22T20:20:02+01:00

Answered 22nd Jul 2012

111.5 mm plasterboard? never heard of that one before but you could try 12.5mm

2012-07-22T20:20:02+01:00

Answered 22nd Jul 2012

hi i tend to use 12.5 mm it is a more sturdy board than the 9.5 mm every person has there own preference

2012-07-22T20:20:02+01:00

Answered 22nd Jul 2012

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