Crease in ceiling

[Arch Stanton]

I have a 1m long crease in my ceiling. When the light hits it at the right angle it is quite noticeable. At its worst point it sags a couple of millimeters.

Ceiling crease.jpg

What are my options for fixing it?

[droog]

First get in the ceiling and see what is happening up there. The cause for it may well determine some of the solution.

And when did it first appear, did it happen suddenly or did it slowly get worse over time?
Are there plaster problems in the rest of the house eg movement ?

[Arch Stanton]

It's a hundred year old building that has been converted to apartments 25 years ago. I've been here 2 years.

The original building is rock solid. This ceiling is part of a mezzanine that was added when they converted the building to apartments.

The crease has been there ever since I moved in and hasn't gotten any worse. Nothing is falling down but the quality of the workmanship throughout is very ordinary.

I can't get in the ceiling, the cavity is only 400mm deep. The only way to access the area is to cut a hole in the ceiling. The crease is not where the plasterboard is attached to the truss. It looks like they have joined 2 sheets.


Ceiling cavity.jpg

Ceiling crease 2.jpg

[r3nov8or]

Considering your comment "the quality of the workmanship throughout is very ordinary", the first photo looks like a bad plastering job that someone has tried to fix (not so well) and painted over sometime in the 23 years before you arrived.

If it's not moved in two years it'll be for purely aesthetic reasons to decide to fix it. Put a straight-edge over it (e.g. a spirit level) and see how much is required to be removed for it to be evened out. The "patch up" may need to be quite wide across both sides of the issue, so that downlight might come into play, and the patch may still be somewhat noticeable depending on the natural lighting situation.

I saw on youtube recently where someone dressed up a boring ceiling with a fake beam. Maybe that's an option that would suit an "old building" conversion?

[droog]

Hard to see from the pictures but looks like they have not back-blocked the joins.

Without access to above the options to repair are limited unless you cut an opening.
I would scape back the paint and confirm first it is a join, if it is see if you can scrape / sand the fill in the joint down without breaking the paper facing of the plasterboard, use a long straight edge to check the result. Feather the joint with new topping compound out about 300mm each direction.

If the joint is cracked under that paint then the joint really needs to be raked back and re-set using paper tape, do not use easy tape!

For plastering tips have a look here https://www.how2plaster.com/
The above site belongs to Rod Dyson who is a member on here.

PS. I am not a plasterer, just a weekend hack. Any professional is welcome to correct any bad advise I may have given above.

[Arch Stanton]

Considering your comment "the quality of the workmanship throughout is very ordinary", the first photo looks like a bad plastering job that someone has tried to fix (not so well) and painted over sometime in the 23 years before you arrived.

If it's not moved in two years it'll be for purely aesthetic reasons to decide to fix it. Put a straight-edge over it (e.g. a spirit level) and see how much is required to be removed for it to be evened out. The "patch up" may need to be quite wide across both sides of the issue, so that downlight might come into play, and the patch may still be somewhat noticeable depending on the natural lighting situation.

I saw on youtube recently where someone dressed up a boring ceiling with a fake beam. Maybe that's an option that would suit an "old building" conversion?

I'm open to options but the beam idea is a no go. The ceilings are pretty low and I could see that becoming a big job.

If I understand you correctly, the way to fix it would be to cut out a big piece and replace it with the joins on the new piece being on the trusses. Makes sense.

[Arch Stanton]

Hard to see from the pictures but looks like they have not back-blocked the joins.

Without access to above the options to repair are limited unless you cut an opening.
I would scape back the paint and confirm first it is a join, if it is see if you can scrape / sand the fill in the joint down without breaking the paper facing of the plasterboard, use a long straight edge to check the result. Feather the joint with new topping compound out about 300mm each direction.

If the joint is cracked under that paint then the joint really needs to be raked back and re-set using paper tape, do not use easy tape!

Apart from sagging the joint is holding up. There are no cracks. I wouldn't be able to sand it back enough without braking the paper. I'd probably have to sand back 3 - 4mm.

PS. I am not a plasterer, just a weekend hack. Any professional is welcome to correct any bad advise I may have given above.

I appreciate any advice I can get. You know more than me.

[r3nov8or]

Glancing light like this is generally problematic. Attempting to fix that one issue could easily cause more, unless perfectly executed. (Eg you could see the replacement square)

Like droog's suggestion, I'd probably start by scraping out the joint until a straight-edge tells me it's "virtually flat" and I have a couple of mm to fill and feather the edges. Don't be concerned about breaking the paper. Depending on how fussy you are, you'll probably also have to paint the whole ceiling for colour and also to blend the texture of the paint.

[droog]

I wouldn't be able to sand it back enough without braking the paper. I'd probably have to sand back 3 - 4mm.

How can you know you won’t be able to sand it back without touching the paper? It is covered by paint at this point in time.

Unless you have already stripped the paint and can see where the jointing compound finishes and the plasterboard starts, if so post up a photo so we can all be on the same page.

[Arch Stanton]

How can you know you won’t be able to sand it back without touching the paper? It is covered by paint at this point in time.

Unless you have already stripped the paint and can see where the jointing compound finishes and the plasterboard starts, if so post up a photo so we can all be on the same page.

I was working on the assumption that the thickness of any paint, jointing compound and plasterboard paper would only be a couple of mm and the "sag" is greater than that.

My desired result was to get a perfectly flat ceiling and that may have bee a bit ambitious and unnecessary. The rest of the ceiling isn't perfect and it isn't noticeable. I'm now confident that I can greatly improve the appearance following your method.

Thank you for your advice and patience. I'll post photos in a couple of weeks after I've had a crack.

[droog]

I was working on the assumption that the thickness of any paint, jointing compound and plasterboard paper would only be a couple of mm and the "sag" is greater than that.

My desired result was to get a perfectly flat ceiling and that may have bee a bit ambitious and unnecessary. The rest of the ceiling isn't perfect and it isn't noticeable. I'm now confident that I can greatly improve the appearance following your method.

Thank you for your advice and patience. I'll post photos in a couple of weeks after I've had a crack.

Noting that it’s been stable and has not changed over time it could just be a tradie that decided CBF on the day, and a painter that said not my job.
With any repair first step is to determine what and where the issue is, only then can you determine the correct way to repair the issue.

Another option just to cover it up without repair is to use topping compound and feather it out wider so it becomes less noticable.

[ErrolFlynn]

Another idea is to do nothing.

The ceiling in every room in my house shows a similar line. I can tell where every board begins and ends. Perhaps mine is not as bad as in your place, but I have to admit that I hated its imperfect finish when I first moved in. Now, after years of living here, I seldom look up—except when changing light bulbs.

Maybe with the money you save, you could consider some insulation. I see in that photo you put up there doesn't seem to be any.

[Arch Stanton]

Another idea is to do nothing.

The ceiling in every room in my house shows a similar line. I can tell where every board begins and ends. Perhaps mine is not as bad as in your place, but I have to admit that I hated its imperfect finish when I first moved in. Now, after years of living here, I seldom look up—except when changing light bulbs.

I agree, you do get used to things but I am at the stage of painting the whole room and I'll be repositioning downlights and touching up any dings in the ceiling so now is the time.

Maybe with the money you save, you could consider some insulation. I see in that photo you put up there doesn't seem to be any.

I don't have any insulation and it isn't a problem. It is a comfortable environment. Not perfect but pretty good. The area in the photo is the mezzanine which covers 3/4 of the room and then opens up into a void.

Mezzanine.jpg

[Compleat Repeat]

I'd go with Droog on this one, I reckon the join isn't backblocked. IF it REALLY worries you, there is a way to repair the crack without ceiling access. But it is aesthetic only:
Scrape out the entire current joint, paper tape and bog etc, exposing the tapered sheet edges. Cut two or three equidistant rectangular holes cutting both sheet edges, approx 120mm x 60mm each hole, with the long edge of the hole at right angles to the sheet edges. Glue (using backblock cement or cornice cement) a couple of plasterboard squares (say 100 x 100, but as big as you can fit in the hole covered in cement) on the upside of the sheet (that is, inside the hole) overlapping the sheet joints and therefore creating a backblock.
When it is dry, fill it as for a normal sheet join, basecoat, tape etc.
This is messy, but it does work. I plastered a big cathedral ceiling at home before I read about backblocking ..... bugger. That's how I fixed it.