Thread: Fixing up old ceiling and deco mouldings

It will definitely be fibrous plaster. Over the years natural humidity/weather changes, ambient vibration and maybe even a failure or lack of the scrimming (the loops of horse hair coated with plaster which is looped over the ceiling battens/joists)as well as the clouts pulling out of the battens.


Once these ceilings reach that stage they basically have permanently set to that wavy alignment and is extremely hard to rectify. If it was a heritage listed building they sometimes strip the paint and skin coat the ceiling to a visually uniform alignment.


Another and more practical method is to cut the main ceiling sheets out BETWEEN the cornice and re-sheet with new plaster board which is also lighter in weight than fibrous plaster. This method is usually done if the cornice is an uncommon profile of that era and the cost to reproduce it is too high but you can also still get a lot of those profiles from specialist suppliers in which case rip the whole lot out and re-sheet with plasterboard and reproduction cornice.


I appreciate that all this depends on your budget

Originally Posted by rwbuild

the loops of horse hair coated with plaster which is looped over the ceiling battens/joists battens.

I renovated a 1940s house a while ago which didn't have saddles over the joists, just clouts nailed into the joists.

The ceilings were flat throughout the house except in one part of the kitchen, presumably due to long term heat and humidity. I borrowed most of that part to make a powder room after getting into the roof space and clearing out the insulation batts, dust and debris around and especially under the joists, then putting modern plasterboard adhesive under the joists and levering up the dropped plaster sheet because I've been told that cornice cement doesn't work as well as stud adhesive on timber. I used long screws on mudguard washers recessed into the plaster and screwed into the joists. I seem to recall finding commercially made solutions for screwing dropped plaster into joists on the internet, but they weren't readily available. I didn't install new saddles because the short 950mm span across the powder room wasn't likely to sag further once the new wall and screws supported it. I put up a stud wall to keep the ceiling as close to flat as I could get. It wasn't perfect if you got on a ladder with a straight edge and level, but as the powder room was only about 950mm wide with 2.7m high ceilings it was close enough to pass visual inspection from the floor. I know this because the nit picking building inspector who checked my renovations for the purchasers missed it, and so did the house designer who bought it. Anyway, if I recall correctly, the tolerance for plaster deviation from straight on flat surfaces is 4mm over 2 metres, and I was pretty close to that on a ceiling that probably didn't have to comply with current standards because it was the original ceiling.

The ceiling on the kitchen side of the new wall still had bows reaching out about 450 to 600 mm from the cornice, which were fixed by removing the cornice and filling the valleys with a few application of basecoat screeded with a straightedge across adjoining low points on the plaster sheets. It's probably the same process rwbuild mentioned as skim coat. The problem with this over a large area is that if you've got fibrous plaster already sagging enough to be readily visible, you're going to be adding a fair bit of weight to a ceiling already failing.

Originally Posted by rwbuild

Another and more practical method is to cut the main ceiling sheets out BETWEEN the cornice and re-sheet with new plaster board which is also lighter in weight than fibrous plaster.

Definitely. And probably much longer lasting. And could well come out cheaper, especially if Angela567 can remove the old ceiling herself. The only problem with this is the massive amount of dust that will fall when the ceiling is removed, which can be dealt by doing it in small easily lifted sections with tarps on the floor and sealing around the door to the room you're working in. There's probably some sort of binding product that could be sprayed on the dust in the roof to stabilise dust before it's removed. Bag up the debris in the sealed room before taking it outside and you will minimise the dust in the rest of the house.

Originally Posted by rwbuild

This method is usually done if the cornice is an uncommon profile of that era and the cost to reproduce it is too high but you can also still get a lot of those profiles from specialist suppliers in which case rip the whole lot out and re-sheet with plasterboard and reproduction cornice.

Definitely, again.

I needed a cornice profile about 2 m long for this job that none of the specialist suppliers could provide from stock. I was quoted about $600 just for the mould to be made, plus whatever it would cost to cast the cornice. I took the cornice profile to a timber machinist who charged me about a tenth of the cost just to make the mould. I probably could have done it myself with a router but the machinist did a better and time saving job. Nail it into the studs and ceiling joists and fill the holes and you can't tell the difference.

Originally Posted by Angela567

The paintwork looks like someone painted over old rough paint. I would like to upload a picture from my library but it seems you need a url.

It could be textured paint under the topcoat(s), which was often used to conceal hairline cracks and other defects, which was certainly available in the late 1970s to early 1980s and maybe outside those limits, because I was using it then for that very purpose on fibrous plaster which is prone to hairline and other cracking and defects over time.

Depending on when the topcoat was applied it might have its own set of problems in getting modern paint to adhere to it. And if the basecoat isn't sound, notably if there are signs of chipping or peeling, then given the age of the house it could well have kalsomine paint on it which may have to be removed to get a good base. It's not a fun job. You need a painter to look at it to see if it's sound.

These could be further points in favour of removing and replacing the whole ceiling.

Originally Posted by Angela567

I have wavy ceilings. The house was built around 1925.
Someone advised me the ceilings could be made of horse hair due to the waves.
I would like to keep the cornice mouldings and have ceilings without the waves.
The paintwork looks like someone painted over old rough paint. I would like to upload a picture from my library but it seems you need a url.

Anything can be repaired but comes at a cost, that will be time and labour or paying someone to do it for you.
Do you have the skills to tackle it yourself or do you have the funds to pay a tradesman to perform the work.
You will probably need a few posts before you can upload pictures, once we see pictures we will be better able to suggest a course of action.

Originally Posted by Angela567

The house was built around 1925.

Before you take another step, check whether your house is subject to a heritage overlay or control which will prevent you doing what you want. I doubt heritage officers in Sydney are less obstructive and unreasonable than many of them in Victoria.

Perhaps your first and irretrievable mistake would be to ask your Council or planning authority for advice and flag to them what you're proposing to do. If you can't find the information yourself it could be worth spending a few dollars with an independent planning or heritage consultant who can interpret what usually are quite confusing, vague and often contradictory regulations and policies. They might also be able to give a way of dealing with it without what in Victoria can be a tedious and relatively expensive process for what are really necessary and minor repairs that don't warrant the expense of planning permits.

Originally Posted by 419

Perhaps your first and irretrievable mistake would be to ask your Council or planning authority for advice and flag to them what you're proposing to do.

Totally agree to understand council requirements, however I doubt there would be any objections to the OP’s intent.

I would like to keep the cornice mouldings and have ceilings without the waves.

Thankyou for the comments.
Sorry for the late reply but I had technical issues with signing in. I think I posted too early after registering an account. I’ve attached photos. You need to click on the photos to appreciate the texture of the paintwork fully.
6699082A-8F9C-4EBC-82AF-146B4631EB34.jpg
We are in the process of organising a company to clean up the roof cavity for an attic ‘landing’ and this will include removal of the old insulation and vacuuming out dust. I am questioning if the ceiling can be improved from inside the house - like in a few years. I was thinking we may have to arrange to cut out the ceiling like you say.

The waves are more noticeable at certain times of day/ light. A friend thinks we should accept the waves.

It’s Sydney and the semi is not heritage listed (more interest around here to knock things down for high rise).

A0714D94-7133-43EF-9995-EA9F76A13CE0.jpg

I did have an old Victorian terrace many many years ago and remember dad helping me and he used screws for a small section of ceiling. He was working alongside a painter who was probably giving advice. But this is a bigger job. I will organise a professional to come out and have a look at it but just wanted to get initial advice from the forum.

Once the roof space is clear you need to inspect to determine where the problem lies.
In some older construction the plaster was fixed by using straps of rovings and plaster over the timber beams in the ceiling, sometimes these detach causing the plaster sheet to sag. To rectify you carefully lift the sheet back in position and repair the fixings.
In other cases the plaster sheet can sag with age in between the fixings. To rectify the only option is to lift the sheet and provide additional strength or support between the existing fixings.

First step is understand what is the problem with the existing ceiling.

Originally Posted by Angela567

I’ve attached photos. You need to click on the photos to appreciate the texture of the paintwork fully.

You might want to speak to someone with knowledge of plaster finishes of the period, in case that's the original finish as it doesn't look like the usual age damage to fibrous plaster or a competent later plaster repair. Or maybe there's been surface damage / lifting paint and it's just been painted over without repairing the damage / lifting paint.

Originally Posted by Angela567

The waves are more noticeable at certain times of day/ light. A friend thinks we should accept the waves.

As long as you get a positive opinion from someone qualified to give it on the integrity of the ceiling, your friend might be on the right track. Looks like you have downlights which are probably best for minimising wavy ceilings, depending upon their placement and beam angles. If the ceiling is sound, it would be a lot cheaper and much less disruptive to get a lighting expert in to see if anything can be done to improve the visual impact. An interior decorator might also be able to suggest simple changes, such as window coverings or paint colours, to deal with daylight issues.