Ceiling help

[deema]

I have a problem that I can’t think of a simple solution for. The plaster for the lounge ceiling in an area has come away from the latte backing and is loose. Never come across it before where the ceiling has remained completely intact and come away from the lattes. Investigating, the plaster wasn’t properly pushed through the lattes in the area when it was done.....circa 100+ years ago! It’s a big room and I’d like to try and keep the ceiling as it has intricate plaster mouldings etc.

I’m thinking that there must be a way of ‘gluing’ the plaster back to the lattes? I can push it back up to the lattes so propping it up would work if I can then fix it. I can’t think of a suitable glue that would be runny enough to fill the voids, have enough open time and sticks to both plaster and wood.

Here’s my initial thoughts

Runny plaster pored between the lattes?
Watered down PVA glue initially pored and then perhaps plaster on top? Glue may puddle??
NO more nails or similar beaded down the lattes
Resin - concerned I might get too much in an area and set fire to the lattes...wouldn’t be a good day!
Screwing the plaster to the joists.....old plaster will probably just crumble and pullback.


Anyone done anything like this before or got any suggestions?

 

[porker]

Have done a few bits like this. Usually I would take down and redo the ceiling as old plaster once it starts coming away is difficult to stop. I understand your predicament though if you have nice mouldings you don't want to disturb. I would not consider any type of glue / adhesive as I can't see it working effectively. I would drill and screw the laths back to the joists if you can using plasterboard screws. It is inevitable you may lose some more plaster. Difficult to tell without seeing it. Then make good with bonding or hardwall and finish over the top blended in. It is extremely difficult to make a blend invisible but may be acceptable. I am not a plasterer by trade but used to do quite a bit. I would see if you can get a good plasterer to come and lokk and advise as they would have seen this before and can probably recommend how best to tackle it.

 

[mbartlett99]

When I renovated my house in Savannah this was an issue in quite a few places. I CUT (not smashed - it tends to spread the damage) the old loose plaster out. Screwed/nailed any loose laths back in place. Replastered.

In a couple of places the area was a reasonable size; removed old plaster, cut a sheet of plasterboard roughly to size, screwed that in and skimmed/faired the area.

Still good after 10 years.

 

[stuartpaul]

One of the ways taught in my very old readers digest book of DIY is to pour plaster of paris from above to 'refix' the plaster. It basically forms new keys above and should hold it in place. Good clean before hand to remove all dust etc. You can also add scrim if you want to strengthen the pop.

Given the quick set time of pop you'll need to work quick but I suppose there's no reason why you couldn't use ordinary plaster and leave it propped overnight?

 

[MikeG.]

No! Don't attempt to re-fix the fallen plaster. It won't work. You should re-plaster that area with a lime/ fibre/ chalk mix (Anglia Lime, Sudbury have pre-mixed bags if that's your area). If you are worried about the rest of the ceiling then screwing through the existing ceiling into the joists, with large washers sunk below the top of the plaster, is the best method (it is what is recommended by the Society for the Protection of Ancient Buildings). If your joists are oak you should use stainless steel screws. The washers are sometimes called penny washers. The new screw holes can be filled with lime plaster or with a Polyfill-type filler, sanded off and the ceiling redecorated.

I am about to go through this very process in my bathroom, and then in 2 adjacent bedrooms.

This is the type of washer to go for, as it provides a key for the plaster.Here's a plastic version, which might be better.

Lattes? They're laths around here.

 

[mbartlett99]

No! Don't attempt to re-fix the fallen plaster. It won't work. You should re-plaster that area with a lime/ fibre/ chalk mix (Anglia Lime, Sudbury have pre-mixed bags if that's your area). If you are worried about the rest of the ceiling then screwing through the existing ceiling into the joists, with large washers sunk below the top of the plaster, is the best method (it is what is recommended by the Society for the Protection of Ancient Buildings). If your joists are oak you should use stainless steel screws. The washers are sometimes called penny washers. The new screw holes can be filled with lime plaster or with a Polyfill-type filler, sanded off and the ceiling redecorated.

I am about to go through this very process in my bathroom, and then in 2 adjacent bedrooms.

This is the type of washer to go for, as it provides a key for the plaster.

Lattes? They're laths around here.

Yup done it that way too for smaller areas or when it started lifting on the sides of a long crack.

 

[giantbeat]

I have had this very problem in our spare room in our 1900's terrace... i notice the ceiling looked odd around the loft hatch, on closer inspection it had broken away from the laths all the way round the hatch on 3 sides, the loft hatch had been fitted when the house was rewired 5 years before we moved in.
The plaster was completely intact, and was just sagging about 1" from it. went above and checked and when the house was last rewired it looks like they gave the loft a good clean out of soot & pretty much removing all the squished plaster that had come through the lath around the hatch before putting fresh insulation down.


after some head scratching i came up with using PU expanding foam as a glue, its sticks to everything right?!!, i squirted pu between the laths & ceiling via the straw in small blobs & then the Mrs pushed the ceiling back up from below using props & boards between the ceiling with me holding the boards as she did to make sure we had a good solid fit , we did about 1sq meter at a time and i squirted a small additional amount of PU through every 6 -8 inches once each section was back in place, it expanded & squished through the laths as plaster would... if not a fair bit more.

That was 7 years ago, its the most solid piece of plaster ceiling in the whole house.

 

[deema]

I like the idea of both plater of Paris and also expanding foam. My home is an old Chapel built in 1803, although not listed I would like to save the ceiling. Thanks for your suggestions.

 

[llangatwgnedd]

Find the joists and plasterboard the whole ceiling
I have seen it patched with a coat of Caling bonding, then skimmed

 

[MikeG.]

I like the idea of both plater of Paris and also expanding foam. My home is an old Chapel built in 1803, although not listed I would like to save the ceiling. Thanks for your suggestions.

These are a bodge. Do the job properly, as I described, if you want to save the ceiling and do the right thing for your old building. I'm an architect specialising in ancient and listed buildings, so know what I'm talking about. If you want a technical picking apart of the suggestions you've had I'll bore everyone to death, but they are poor ideas. The proper solution is extremely straightforward, and well within the capabilities of the average weekend DIYer, and I urge you to reconsider.

 

[MikeG.]

Find the joists and plasterboard the whole ceiling

You missed this, obviously:

.... I’d like to try and keep the ceiling as it has intricate plaster mouldings etc.......

I have seen it patched with a coat of Caling bonding, then skimmed

Carlite?

A lath and plaster ceiling will be lime. You shouldn't mix lime and gypsum. Lime is completely straightforward to use (add water to the right consistency, then apply in the normal way). With the product I specified, you can do it one coat if you want, although the likelihood is that you'd do it in 2. It really is simple.

 

[deema]

Hi Mike,
Thanks for the replies, I really value your opinion. The area affected includes a moulding that if I remove the ceiling will not I fear survive. I know it’s possible to take a cast and make new to replace.

I’d appreciate knowing why the ‘bodge’ solutions are a bad idea if you could take the time to explain.

Some parts of the Chapel are built really well, for others it’s clear that the famous company Bodgit and Scarper have been in existence for a number of centuries!

 

[MikeG.]

I'm not suggesting removing anything at all. I am suggesting screwing through the loose areas of plaster into the joists, using a big washer to to spread the load, then repairing the screw holes afterwards. I'll be posting photos elsewhere in the next 10 days or so of me doing just exactly this for my really saggy loose ceilings in my old cottage. I ordered the plastic washers I linked to previously, straight after I posted the link on here.

Trying to glue back loose plaster will never work. Imagine trying to glue back a piece of plaster which fell off a wall? It would never be good enough, always sitting slightly proud of the surrounding plaster, and only held on here and there. The edges would always be cracking, how often you filled them. That's before we start looking at hard inflexible materials such as Plaster of Paris and PU glue fixed to a soft, flexing combination of materials like like plaster and laths. If it's not good enough for a wall, it isn't good enough for a ceiling, and you would always regret doing it.

The thing is, doing the proper repair here is actually a very straight forward exercise. It isn't like you need any specialist tool, knowledge or skills. Do it on Saturday morning and you'll be finished in plenty of time to watch the rugby.

ETA......for some reason I thought that a patch of plaster had fallen off, in addition to the loose stuff. You can therefore ignore anything I said about replastering the fallen patch.

 

[deema]

Hi Mike
Thanks for the detailed reply. The ceiling is completely intact at the moment, no cracks or bits dropped out at all. It’s just an area has come away from the lattes and has dropped and will I’m sure without attention get worse / fall down.

 

[MikeG.]

..... come away from the lattes......

I'm intrigued by your use of the word "lattes". Is this a local term? It's not something I've come across before (they're always just laths, in my experience).

Don't put this off. Get your washers ordered now, and screw that back up as soon as you can. A falling ceiling can do a lot of damage, and it will be ten times more work to repair. A stitch in time, and all that....

 

[deema]

Hi Mike,
Lattes is a name a friend of mine gave to them When making a point. It just stuck with me and makes me smile. It was something about a ceiling is an inverted cup of white frothy coffee, brown plaster with finish white plaster on top and he pored the coffee over a young chap who’d got it the other way around!!
The good old days when a welders initiation could be that they had to weld their steel toe caps together and then be hung by them upside down 50 feet in the air from the nearest crane......fond memories!