plasterboarding ceilings

[Fred]

Hi,

I was wondering, what is the correct way to plasterboard a ceiling? Do you save time by screwing it over whatever is already up there or should you make a mess and pull the old one down first?

Is there a good way of pulling the old one down? I imagine that if you have access, the best way is to hit it with a mallet from above? Failing that, do you cut a hole, put your hand it and pull?

Or does it depend on the type of ceiling?

A friend of a friend has moved into a house and pulled down the lathe and plaster ceiling and boarded and skimmed that.

When we moved here, in the days before I had tried plastering, I got a man in, and he suggested we pulled the old plasterboard ceiling down and re boarded before skimming. He said it was easier to plaster onto fresh board. I have had a go at plastering since, but only walls, not ceilings, and I have found this to be true: my attempts on plasterboard were quite good but not so good on an existing wall. I wonder why? (BTW, it was only a small ceiling; he said he would have skimmed over the existing ceiling had it been a large room).

TIA

[GMM]

That's hit the nail on the head - it must depend on the ceiling and the reason it needs dealing with.

Taking down L+P is a messy old job: It's tough stuff and takes a lot of swearing and cups of tea, as you pretty much have to cut through, or lever off, each lath. I took some L+P walls down this year and it took a lot of work. Basically I found the timber studs they were built onto and cut parallel to them through the L+P (making a mess of a few saws). Even then it didn't come off easily and took a lot of time to prise each little stub of lath off.

PB is loads easier: Once you make a hole you can almost pull it off by hand (though something to lever it off with with helps a lot). Still makes a hell of a mess though.

I think it would have to have a real defect before it was worth the trouble for either. For example, L+P can become detached in places and sag, or either sort might become significantly water damaged. If it just needs a skim I would leave well in place.

In my estimation, you have to be pretty good to plaster a ceiling well, whether skimming over the existing or fitting new PB. If it was sound but had a crappy surface that needs skimming, I would find a decent plasterer who probably won't cost you a lot more than going to all that trouble and will do a much better job.

Of course, if you do get someone in, it's always worth watching to pick up some tips for when you next have a go.

[Phil L]

If the ceileng is heavily bowed then it may need to come down, if it's already fairly flat then it stays up

I always just board over whatever is there - first you need to find the joists at each end and mark the centre of each one with a pencil, this will require the mashing of a hole, but make it away from the wall by about 6 inches*, then, once you have made the marks for all centres at each end of the ceiling, get a chalk line and with the help of an assistant, ping a line running from mark to mark, then plasterboard and skim.

If the ceiling is just artexed, it doesn't need plating, simply scrape off the snots and apply PVA mixed 1:1 with water and allow to dry, next day another coat of same and skim

[Phil L]

*forgot to add.... when screwing the new pb's up, the end screw is very close to the wall, then the next one is about 9 inches away, if you make the hole close to the wall the screw will pull through the board.

[meow2222]

Pulling old L&P down is a nightmare. Everything in the room gets trashed, all the paintwork, the lot. Leaving old pb in place also gets you better fire, smoke & noise absorbption ratings.

The downside of overboarding is its harder to see where exactly the joists are.

NT

[R D S]

I've boarded over a ceiling in our house, it looked OK until we decorated and then it was apparent that it was wavy.

Another, we pulled completely off, took a lot of time and made a shitload of mess and it was better but not 100% level.

The last one we did we made a new frame and screwed the boards to that. It was perfectly flat when finished, didn't take an awful lot of time, was arguably the easiest way of doing it and didn't involve a massive amount of expense. No good though if you can't afford to lose 3 inches.

[harry]

It's best to take the old ceiling down. If you don't, it's hard to make and nail the joints (on to a single joist) apart from anything else. So long as you have something to hold on to, (even another person) and there is access, I quickest way to get the old ceiling down is to stamp on it from above. A jemmy is ideal for getting the old nails out. Remember to put scrim on the joints of the new plasterboard or cracks will appear.

[harry]

If there is no access from above, A jemmy is the best way to get an old lathe and plaster down. You put the back of the jemmy on the joist and lever each lathe off.

There is an alternative for lathe and plaster. You bash the ceiling with a hammer between the joists until the plaster falls away and scrape away any bits left on. Leave the lathe in place and nail the plasterboard on top. You need longer nails of course in case you hit a gap.

[Steve Firth]

harry wrote: [snip]

Don't worry if you have put a lathe above a lath and plaster ceiling it will be coming down by itself. Right about ... Now!

[stuart noble]

Last one I took down I ran a plasterbord saw down the joist edges and put the sections straight into a wheelie bin liner. I prised off the remaining bits from the joists with a bolster but, on refection, probably didn't need to. Use of a hammer guarantees dust flying all over the house.

[David WE Roberts]

Everyone seems to be keen on nailing up the plasterboard - has nobody heard of plasterboard screws? Screws plus a powerful driver make short work of fixing up boards and you can get many different lengths of screws.

Overboarding with thin plasterboard (9.5mm) is usually the easiest way to get a good long term result, as long as you follow the advice about locating the joists before you start screwing.

My one concern with this approach is where someone has already overboarded. There will be a limit to the number of layers you can put on a ceiling, although double boarding is standard for increased fire protection.

Cheers

Dave R

[RJH]

Sort of against my better nature (long story) I recently had a new ceiling - he laid battens over the lath and plaster fixed to the joists, then plasterboard fixed to the battens. Been up 6 months and looks pretty good.

Rob

[stuart noble]

Too bloody right, especially if you need the other hand for something

[Fred]

Thanks. I guess the trick is having enough experience to tell when it is too bowed, to know what can stay up and what must come down.

I don't know very much about the chap who pulled down his lathe and plaster because he is a distant acquaintance, so I am not sure how bad his ceilings were in the first place, nor his reasons for doing it. I was told that it made a lot of mess and that all the dust blowing through the window made it look like the house was on fire! A common theme in the replies is how dirty it is.

It's funny you should say that. When the other A-word (the ingredient) gets mentioned here some say it's nothing to worry about and some say it's deadly, so I am never sure whether to run away from Artexed ceilings or not.

What prompted me to post this was that I had been looking at a house that needed some work doing to the ceilings. They were all artexed. One seemed to be yellow/brown in places but I don't think it was a leak, I actually wondered whether it was nicotine? Is it easy to remove? They are quite high ceilings BTW.

In another room, there were cracks in the ceiling. It could be that the ceiling is boarded and the cracks were along the edges of the boards. I am not experienced enough to know whether skimming would cover them. I would expect if the boards are hanging, the new plaster would crack too? Am I right about that? Do tired boards have to come down or can you skim over lines?

TIA

[Fred]

Was the original ceiling level? I can't imagine the joists were not level, so I am surprised that you didn't get a level finish second time around. Could the boards have been bent? Had they been stored standing up?

Why did the frame need to be 3"? Did you screw the frame to the wall or the ceiling, or both? If screwed to the ceiling, I can't see how this is any better than screwing the boards direct and saving the time and hassle of the frame?

Thanks.

[Fred]

Is there a trick to this? If the ceiling is upstairs and the attic is not boarded, I suppose you could push a screwdriver (!) through the ceiling either side of each joist, but this would be difficult to do for a ground floor ceiling, without lifting floorboards upstairs.

You could use a magnet to find nails but how do you know whether those nails are in the centre or the edge of the joist or whether they have missed the joist completely (I have raised plenty of floorboards where the nails were a few mm away from the joist!)

I guess you need to drill a hole to see how thick the existing ceiling is, to ensure you use long enough screws.

Thanks.

[Fred]

skimming over the

needs skimming, I would find a

trouble and will do a

Perhaps best to get a plasterer to quote and see if he says whether it needs boarding or skimming.

[meow2222]

Just drill some holes at each end to determine where the joist is, after tapping it to get a fair estimate, and draw a line. With L&P it avoids bringing a century of muck down and leaves you with better noise and fire performance.

NT

[meow2222]

[Tim Watts]

Rare earth magnet is what I use to seach for joist nails. Works surprising well. if you get a few magnets, you leave them up as a guide then "fit" a straight line through them.