Hairline cracks on new plaster ceiling

FlaatusGoat

Had my ceiling replastered a week ago and unfortunately some long hairline cracks have formed. Before I paint my top coat on it is there anything I can do to hide or reduce the visibility of the cracks? Would trying to smear filler over them be overkill or ineffective......

rob7475

Was the ceiling plasterboarded at the same time? Did the plasterer use tape over any joints? If it's been boarded but not taped, the cracks may keep coming back even if you fill them.

Occasionally, new plaster can get a few hairline cracks if it dries too quick etc. You can run a blade along the crack to create a bit of a groove before filling and sanding which should sort it. I'd be tempted to get the plasterer back though to rectify their work.

the_lunatic_is_in_my_head

https://www.polycell.co.uk/product/polycell-3-in-1-basecoat/

I wasn't that impressed with it to be honest, I think the cracks have to be really, really tiny for it to work. 

This 

https://www.thepaintshed.com/tikkurila-anti-reflex-white-2?gclid=EAIaIQobChMIgdf6uYv6gQMVLTfUAR0mawvdEAQYASABEgIKcfD_BwE

will hide most imperfections as it doesn't reflect much light at all, well worth the money, the two combined might hide the cracks if they are small enough. 

FlaatusGoat

This is what I'm dealing with unfortunately. I've just run a blade through them so hopefully they're fillable....

the_lunatic_is_in_my_head

Forget the Polycell, it won't cover those cracks. 

More knowledgeable posters will hopefully comment, I wouldn't be happy with that personally. 

Confusedlad

I had similar. Get the plasterer back. Don't try to fill it yourself. The polycell product is good for hairline cracks but it looks to me probable that no tape has been used (common c 30 years ago). Better tape products now exist and should ALWAYS be used over joins.  Plasterers can also use 'enhanced' plaster to solve this is but this is often only a temporary fix if the joins have not been taped properly.  A good plasterer will return and make the job a good 'un.  Let it dry fully, then get the workman back.

FlaatusGoat

Confusedlad said:

I had similar. Get the plasterer back. Don't try to fill it yourself. The polycell product is good for hairline cracks but it looks to me probable that no tape has been used (common c 30 years ago). Better tape products now exist and should ALWAYS be used over joins.  Plasterers can also use 'enhanced' plaster to solve this is but this is often only a temporary fix if the joins have not been taped properly.  A good plasterer will return and make the job a good 'un.  Let it dry fully, then get the workman back.

Doubt he'd want to know, paid up already. Looking like the solution to put down filler over the cracks and lay mesh tape on top of them, with another of filler then over the mesh tape. PITA if I'm honest.

ThisIsWeird

That's obviously worse than original as you've grooved it out?

Worth trying the SBR method, on one crack at least - see how it goes? The idea being that'll it'll glue the two sides together before fine-filling.

Vacuum the cracks fully. Brush on SBR liberally, across and along, until it stops drawing it in. Wipe the surrounding plaster surface with a damp cloth to remove SBR before it dries. Once dry, fine surface flexible filler. Sand flat.

Might not work. But might.

FlaatusGoat

ThisIsWeird said:

That's obviously worse than original as you've grooved it out?

Worth trying the SBR method, on one crack at least - see how it goes? The idea being that'll it'll glue the two sides together before fine-filling.

Vacuum the cracks fully. Brush on SBR liberally, across and along, until it stops drawing it in. Wipe the surrounding plaster surface with a damp cloth to remove SBR before it dries. Once dry, fine surface flexible filler. Sand flat.

Might not work. But might.

Thanks but SBR does seems quite dear and it's sold in larger quantities than I'd need for a relatively small-ish area like my ceiling. Plus I don't think it's any less work than laying on the mesh tape and applying the filler on both sides. At the end of the cracks I've cut in relief lines. Youtube to the rescue it seems.

the_lunatic_is_in_my_head

FlaatusGoat said:

ThisIsWeird said:

That's obviously worse than original as you've grooved it out?

Worth trying the SBR method, on one crack at least - see how it goes? The idea being that'll it'll glue the two sides together before fine-filling.

Vacuum the cracks fully. Brush on SBR liberally, across and along, until it stops drawing it in. Wipe the surrounding plaster surface with a damp cloth to remove SBR before it dries. Once dry, fine surface flexible filler. Sand flat.

Might not work. But might.

Thanks but SBR does seems quite dear

Can't comment on the advice to use SBR but £12.10 for 2.5l delivered on eBay

https://www.ebay.co.uk/itm/143919521858

ThisIsWeird

FlaatusGoat said:

ThisIsWeird said:

That's obviously worse than original as you've grooved it out?

Worth trying the SBR method, on one crack at least - see how it goes? The idea being that'll it'll glue the two sides together before fine-filling.

Vacuum the cracks fully. Brush on SBR liberally, across and along, until it stops drawing it in. Wipe the surrounding plaster surface with a damp cloth to remove SBR before it dries. Once dry, fine surface flexible filler. Sand flat.

Might not work. But might.

Thanks but SBR does seems quite dear and it's sold in larger quantities than I'd need for a relatively small-ish area like my ceiling. Plus I don't think it's any less work than laying on the mesh tape and applying the filler on both sides. At the end of the cracks I've cut in relief lines. Youtube to the rescue it seems.

Mesh tape is the 'correct' way, but I've seen that fail too, if the boards are still moving (and I am talking about our own recent extension...) So I'll be trying SBR myself.

Adding tape, tho', is a hell of a palaver - feathering in a filling skim enough to make it invisible. Or are you planning to cut a bevelled line either side of the crack, wide enough to take the scrim? And then finish it off to the existing level? If so, great. But I'd still brush watered-down PVA (if not SBR) into that crack before apply the dob and tape.