Hairline cracks in reskim

mvaanderson

Hi,

We had our living room skimmed last November and the job seemed great. We followed all advice regarding painting ie mist coatband sufficient drying time. Over the last week though I have noticed 3/4 hairline cracks on the wall towards the corner of the room, around 3 feet above the radiator. They are diagonal and vary is length and are not joined. The biggest is around 40cm and all are less than a mm wide.

The reason I worry is the block of flats (ours is 2nd/top floor) has a history of subsidence due to a tree which was removed. The building was tracked over several years and everyone was happy there was no more movements and the experts and insurers signed it off.

Are these cracks a worry or simply what can happen when you reskim over plaster? The plaster underneath wasn't in top condition but certainly wasn't falling off the walls!

I would really appreciate it if anyone haa any advice for me moving forward!

Thanks,

Mark

Ps the cracks are hollow when tapped

southcoastrgi

if it sounds hollow then the plaster is no longer stuck to the bricks/blocks which is why it's cracking on the surface

wrightk

I'm no expert on plastering but have had a few plastering jobs done by professionals and family who explain the processess. Skimming over old/dead plaster will cause this as will applying the skim coat too thick.the dead plaster is identifiable by a hollow noise when tapping as you have found.they say 'the plaster is blown'. Ideally the plasterer would have found any dead spots in the plaster underneath and removed to brick/whatever your wall is constructed of then pva'd then applied a suitable bonding coat then skimmed over the top.

I wouldn't worry about anything more serious

mvaanderson

So any advice on what to do next? Would it be worth patching up with filler or does it need stripped back and replastered?

wrightk

What you need to do is knock and identify how much has actually blown ie the size of your palm or more. Filling and sanding the crack will do nothing but hide it for a couple of months at best. If the plaster has properly blown a tap with a hammer and large flathead screwdriver will be enough to bring it down.depending on the size of the hole depends on what you do next!

ceredigion

wrightk wrote: »

I'm no expert on plastering but have had a few plastering jobs done by professionals and family who explain the processess. Skimming over old/dead plaster will cause this as will applying the skim coat too thick.the dead plaster is identifiable by a hollow noise when tapping as you have found.they say 'the plaster is blown'. Ideally the plasterer would have found any dead spots in the plaster underneath and removed to brick/whatever your wall is constructed of then pva'd then applied a suitable bonding coat then skimmed over the top.

I wouldn't worry about anything more serious

I can tell !

ceredigion

wrightk wrote: »

What you need to do is knock and identify how much has actually blown ie the size of your palm or more. Filling and sanding the crack will do nothing but hide it for a couple of months at best. If the plaster has properly blown a tap with a hammer and large flathead screwdriver will be enough to bring it down.depending on the size of the hole depends on what you do next!

Who said the plaster had delaminated

wrightk

ceredigion wrote: »

I can tell !

Still waiting for your advice.......

richy999

I doubt it was anything to do with the quality of the re-skim... you would have noticed sooner if this was the case.

As suggested, it could be that the plaster underneath has blown. It's unlikely to fall off the wall onto your head so don't worry too much about it.

You have two options:

1. Widen the crack, fill it, touch up the paintwork and ignore.

2. Investigate further and be prepared for it to be stripped back to bare brick completely re-plastered.

I would monitor it for a month or two then if no further cracking takes place, choose option 1.