I'm about to dry-line a ceiling in my flat following removal of the old and crumbling lathe and plaster one. Going for 12.5mm board with tapered edges. A couple of questions before I start:
Which side faces down, white or brown?
I'm happy with taping and sealing the tapered joins but what about the joins between the 1200 sides of the boards where there is no taper. Do I need to prepare these edges in any way or just butt them together as best as possibe?
Leading on from this, which joins shouls run parallel to the joists, the tapered 2400 ones or the non-tapered 1200 ones.
I've removed the old ceiling but left the ornate cornice in place, with the intention of butting the new plasterbord up to the overhanging edge of the cornicing. How do I make a sufficiently good join here to ensure I won't get cracking in future? If I used tape, it would have to be applied half on the plasterbord and half on the underside of the cornicing, which would abviously spoil the edge of the cornice. Is there any other way?
The edges of the boards should go tapered edge to tapered edge, unless unavoidable, if not it isn't a big problem really. As for the joint tapeing you should tape all joints between boards. Also the edges that arent tapered you should try and get an edge that you haven't cut (the edge that is there from the board being delivered) to meet another edge of the same kind, for example when you cu your first board the edge which you hae cut will be rough and this should go against the wall, if you follow this you willl end up with all the neat joins in the middle of the ceiling.
As for the cornice i would rip it down and put up new, depending of the size of the ceiling it shouldn't be expensive, preserving the old would be too much trouble.
hope this helps
Thanks Jay, just one point, where I've got non-tapered joints, will the application of the tape and jointing compound not produce a lump in the ceiling along the joint. Obviously the point of the tapered edges is to produce a channel for the tape and jointing compound to 'fill-up' and produce a flush surface. If the channel's not there, the tape will be raised off the board surface and produce a lump. Is it just a case of blending this in as best as possible?
The reason I'm saving the original cornice is that it's very old and very large and is actually very impressive. It gives the room a real character, and I would like to preserve that. I've looked into the costs of a like-for-like replacement cornice and the price is extortionate. I'm on a tight budget at the moment and can't afford to splash out that sort of cash.
I guess the first question is do you know where I could buy a suitable replacement cornice without paying the premium that goes with them. I must admit it surprises me that with todays materials and extrusion technologies, this stuff can't be churned out far cheaper. Maybe I haven't looked in the right place yet!
Failing that, and despite the dificulties, whats the best approach going down the route I described before and keeping the original cornice?
if you are losing the tapered edges then taping and jointing is going to be difficult. couldn't you skim the whole ceiling?
plaster moulding remains an expensive technique, its the moulds manufacture, machiner and labour that cost the money.
could you slide the plasterboard over the cornice? this would leave a smaller gap less likely to open up. or how about rebating the edge of the plasterboard so that it could be slid over, then use a decorators caulk. also proper coving adhesive is very good for gap filling, put it on wet then wait til it goes off a bit then work it. it can even be sanded. ive never had a problem with it cracking. thistle make a good one.
just too add maybe if you could buy thin board that will slid above the cornice as chris said.
another way around it would be to do as you said originally and it will probably leave a gap around the edge between the cornice and the board what you would do then is crap old newspaper or any old paper into the gap that is left until there is enough there to stop a filling compound going into the gap behind the ceiling board, then you can mix a small amount of finish ( or other compound, i think most will do the job) and go around filling out the hole, but make sure you leave it flat let it dry and then skim the whole ceiling again .
i would personally do it that way if it was my house and i had nice coveing.... if only :P ( the coving at my house is polystyrene, left by preious owner) hope this helps
just noticed another question in your original post and this is how the board will run along the joist[img][URL=http://img84.imageshack.us/my.php?image=ceilingdt5.jpg][IMG]http://img84.imageshack.us/img84/4177/ceilingdt5.th.jpg[/IMG][/URL][/img][/img]
loads of good suggestion already been made!
You want white side down, so it is what you see when the ceiling is up as this is where the tapered edge is on the board (not grey side)
Boards should run in rows using 2400mm length and then butting 1200mm end to it. The next row should be staggered so the joint where the boards meet on 1200mm side, do not meet up.
(i.e. say your first board you put up is the full length of board 2400mm, the board on the next row should be cut back to the next joist/nogin say 2000mm then all joints will be staggered there after, then next row full board agian or cut smaller than the 2000mm board on the previous row)
You should slide board under cornice if you can, if not but up to it. then fill any gaps with decorators chalk if not to big a gap, if gap is big fill out with your jointing compond or filler, you can put a flat tape around the egdes of the wall where board meets cornice and fill that out if edges are not tight up. As for non tapered edge on board (1200mm edge) a lot of dry-line tapers. Just tape it and fill it out with a good spread of compound.
But if you really want a tapered edge I used to get fill the cheese grater type and run it down that edge of the board to create a tapered edge. The only problem is thjat it takes the outer white skin of the board that holds the plaster bit of board in place and if your not careful will crumble or break when screwing board up.
Bit long winded but think I have answered your question and others have touched on things I have mentioned, so total respect!
Good luck mate, hope you enjoy your DIYing. If you have any querrys post on this site, some great knowledge knocking about.
Thanks for all the replies everyone. I've had a look at the option of sliding the new plasterboard over the top of the cornice, sounds like a good plan. I won't be able to get all the original ceiling out but should be able to take about an inch or so out so that I can slide the plasterboard over the tip of the cornice and as suggested fill the gap with a bonding compound. HOWEVER........what I haven't mentioned until now is that the room has had an en-suite added in one corner which now leaves a few metres of new wall with no cornicing at the ceiling joint. My plan, get ready for a laugh, is to buy some silicon moulding compound of the net and make a mould of the existing cornice in order to cast some new lengths. I can then fill in the missing sections, take all the paint off the original bits, repair the damaged and broken bits, sand it all down, etc etc.........getting tired jut thinking about it.
Maybe I'm better off taking the whole lot off and putting up new. I did find some more reasonably priced stuff on the web, for about Â£20 per metre, which looks very similar to what I've got. Can't decide, can't decide......
Brownie, I like the idea of shaving off a taper along the 1200 joins, this would mean a better finish in the long run I think. I did think about skimming the whole ceiling, but I can't seem to get the hang of this plastering lark, despite having watched a teach-yourself-plastering DVD. The stuff oes on ok but I always end up with a slightly undulating surface. I guess there no substitute for professional training. It's not that I mind paying a plasterer for it, it's just that the whole flat is getting renovated and the wallet's getting thinner by the day!
Jay, I can't get your link to work, but I get the idea. I agree it would be better to keep the original cornice but it would take a lot of time to get it back to it's full glory. I've just finished renovating a really intricate cornice in the living room which took me about a month to do, although it was far mor intricate than the one I'm discussing here. It takes a lot of time to fill the missing bits, sand it all down and getting it looking perfect.....
I have just had a little thought that may help in the long run,
Regarding Slipping boards over top cornice, if you can work out what the gap may be, and say you use 12.5 thick plasterboards and the gap before boarding is 20mm you could run wood lathes over joist, packing them out 7mm in this case to reduce gap saving an awkward job latter and if greater than 25mm double board ceiling.
Just a thought,
The shaving the end of boards does give a better finish, just rememeber to taper it in a way that you can apply tape and fill out.
i'd search net for cornice suppliers you can buy from DIY. But could be someone local to you that specialises.
Good Luck agian
PS. be careful with shower in room as they are certain regulations that must be complied to regarding electrical safety and water ingress protection ratings. It comes under part p of building regs and electrical regs are changing this year.