Boarding over ceiling

[russella]

Hi all,

I'm planning on boarding over an existing ceiling upstairs, and I've got a couple of questions that I hope someone can help me with! The existing ceiling is lath and plaster, the joists are 3 1/2" x 1 1/2". spaced about 35cm apart.

I plan to screw 2 x 1 wooden battens across the existing joists, then screw the plasterboard to these wooden battens, this gives me a bit of clearance so that I can get the edges against the walls nice and neat, and it helps with a section at the edge of the room where the roof cuts into the room for a foot or so. Are there any problems with this method?

1. Do I need to use 12.5mm board, or could I get by with 9.5mm? I heard that 9.5mm is "whippy", but with no traffic above (it's just a loft) and with the existing ceiling still there, I'm slightly worried about the extra weight.

2. If the boards are going to be skimmed when I'm done, does it matter if the boards are staggered or not?

3. Am I going to have any problems if I use 900 x 1800 boards instead of 1200 by 2400?

Thanks all!

Russ

 

[1john]

counterbattening is fine, you can pack them where required to straighten up an older ceiling that may have settled with the joists.

1 - use 12.5, they wont sag as much with time

2 - staggered is better if possible or you way end up with a hairline the whold length of the room

3 - 1800x900 are fine, i had to use some in my house cos full boards wouldn't fit up the stairs

although if you were to counter batten at 300mm centers (which suits the 1800x900 boards) at 90 degrees to the existing joists then 9.5 would be ok, personally for the extra few quid I wouldn't bother though.

 

[troweladdict]

as m8ty said 12.5mm boards skrim the joints two coats of 4/1 mix PVA
2 good coats
then 2 coats of board finish sorted then a 2 coat mist coat

 

[stevethespreader]

edited

 

[stevethespreader]

alway stagger boards for strengh i don't see any need for counter batonning on most ceilings on this particular ceiling i had limited board size as the client had already cut them to fit into his car View media item 23733 View media item 23734 View media item 23735 View media item 23737

 

[JMLanders]

Counterbattening does enable you to get some of that silver foil bubble stuff up there for insulation if it's an old and uninsulated room. We did it where we had a flat roof above it; it was wellworth the effort and the room is considerably warmer now in winter and not so boiling in summer.

 

[Richard C]

Use 12.5mm boards & I go with Steve on staggering & counter battening unless you’ve no choice, why create unnecessary work! Use full size boards if you can, I’d be very surprised if you can’t find a way to get them up a conventional staircase & I’ve yet to be beaten. They really aren’t that difficult to manage & the fewer joints the better = less chance of cracks.