skim cracking

[Steve]

In 2010 I had my lounge skimmed, and now there are long hairline cracks everywhere!!!

Is this normal? Why has it happened? The house is 100 years old, is it because of minor movement? Or the plaster drying out? The plaster skim coat was done over a very rough old plaster, so thought it'd do well in terms of "sticking" to the wall!

 

[PrenticeBoyofDerry]

When did you first notice the cracks?
what condition was the then existing rough old plaster?

 

[ryme64]

it is sticking. or is a crack that important.

 

[noseall]

It is not unusual. Often the cracks will emanate from the corners of a door casing or window etc.

It can happen on new plasterboards.

Skimming should never be relied upon 100%.

In fact all plaster to some degree will be vulnerable to cracking, some more than others.

There are many factors which can contribute, but i will say that a brick built structure (internal skin) that has been wet plastered will probably fair the best.

The worst buildings are those built on clay out of lightweight aerated blocks that were laid wet.

 

[joe-90]

The worst buildings are those built on clay out of lightweight aerated blocks that were laid wet.

Amen to that.

 

[simonjay]

The worst buildings are those built on clay out of lightweight aerated blocks that were laid wet.

Amen to that.

That'll be most new houses then

 

[PrenticeBoyofDerry]

It is not unusual.

I feel a song coming on!

 

[noseall]

Arf, arf!

What i will say is that skimming over walls is by no means a panacea for all things cracking, far from it.

If it was prone to cracking beforehand then it is likely to crack again.

However we have had the greatest success with over-skimming by preparing the walls or ceilings with a product called blue grit.

Expensive but good stuff. Worth the extra dollar.

 

[ImperialCompleteSolutions]

I go to a lot of jobs where the plaster has cracks in it and it needs skimming, the trouble is if the plaster is cracked it can sometimes mean the browning has become "live" (lost suction to wall) and over skimming does not sollve the problem as the backing coat is loose and as skim is only 2- 3mm thick and will eventually crack.

I tend to scrim over all hairline cracks first, this helps ! but to solve the real problem you need to take all browning and plaster off wall ....... alot more expensive !

The trouble is you tell customers what need doing and they run a mile understandably, they then get joe blogs in to skim room at a fraction of cost and a year later the cracks re-appear.

I have done plenty of skimming jobs where really it need chopping off completley but I always warn customers that skimming is not guaranteed to recrack !

 

[Nige F]

blue grit.

Expensive but good stuff. Worth the extra dollar.

I feel a film coming on - John Wayne-Carr in Blue Grit

 

[joe-90]

Funnily enough I thought the same thing.