Would it be dangerous to just repair?

[HomeReno24]

Hi, just looking for some advice...

There are some cracks on the celing in a Victorian flat we've just bought and we're working out what to do. I was wondering if someone could help? We've had a few different quotes and have been told different things, so not quite sure what to do.

Just looking to the celing, we probably wouldn't have thought to do anything, however the surveyor said the plaster has been debonded from the timber lath substrate and will require significant replastering over the years.

We've been told we could put joint tape where needed and repair the crack to having to completely take down the whole celing and redo it, so not too sure what we shoud do.

My main worry it how dangerous it would be to just repair the crack, is it possible the whole ceiling would just fall down?

Money is an issue at the moment so also don't want to pay to have the whole celing redone if it doesn't really need to.

Any advice would be great, thanks!

 

[HomeReno24]

I've attached some photos for a better idea

 

[Koolpc]

You try making holes along the cracks and inserting low expanding foam in there. Seen this several times...

 

[HomeReno24]

Thank you for your reply, will look into how to do this

 

[opps]

As a decorator, I rake out the crack. There may be a lot of very granular old plaster that drops out. Do not be too aggressive when raking out. If you end up with a rather wide crack, in excess of about 7mm, use a brush to remove any loose plaster. Mist the area with water and spray in expanding foam. The water helps the foam to stick to the plaster and increasing curing times. Ideally, some of the foam will run up above the lathes and help to hold the plaster up (to a degree).

If you do purchase expanding foam, I would strongly recommend buying a canister of gun cleaner. Expanding foam is extremely sticky. The gun cleaner will help you tidy up any "mistakes". The cleaner is basically acetone in a spray form.

BTW, most canisters of foam will only work if the can is upside down. Some, eg Bond-It Mega Foam, will work at all angles

Once the foam has cured, use your fingernail/whatever, to remove the excess and then fill with something like RedDevil OneTime. It is a lightweight filler that will allow for a (very) slight degree of movement. A major advantage is that the dust generated when sanding will not stick to surfaces (unlike power based fillers).

If the crack is less than 7mm, I clean the crack and brush in PVA, to seal the plaster edge and then (when dry) gun in Toupret Flex and Fill. It is a caulk that has fibres to reinforce it. Use a filler knife to force it as deep as possible. Remove any excess from the surface immediately. It will shrink back as it cures. The next day, face fill with RedDevil.

BTW, the links included are simply to help you see the products.

 

[ree]

OP,
Gently push up at the damaged areas & determine if the plaster has "debonded" from the plaster laths - or if the laths & plaster have "debonded" from the joists?
If its the laths have dropped then:
1. Find the joists that the sagging plaster laths were attached to.
2. Pilot hole through the laths into the joists. This is necessary.
3. Screw through the pilot hole to pin the laths to the joists.
4. Make good.

From your pics there's little danger of the ceiling(s) collapsing.
What's on the floor above the ceiling?
Lightly test all your ceilings and plaster Ceiling Roses for movement.

 

[foxhole]

Save up and replace ceilings , until then no need to touch it.