Blown plaster on chimney breast

[CazB87]

Hi,
I'm new to this forum and have looked over old posts but can't find anything that really answers my problem...
I live in a mid-terraced 1930/40s house - only moved in a year ago and have been working our way around DIY projects since. The problem is in our living room. When we stripped our wallpaper in October/November time all the plaster came off and what didn't was blown so we had some workmen in who replastered the entire room. We are just coming to have our fireplace sorted out (eventually!) and have noticed that the plaster on the chimney breast is blown again.
I could be quite accepting of this but as I paid over £300 only 5 months ago I'm not very impressed and don't really want to hear the words replaster!!
The plaster has got hairline cracks about a footish above the fireplace opening and they go up by about a foot as well. I've done the old tapping trick and its definately hollow sounding! The chimney breast is on an internal wall.

I really want advice on why this has happened so soon? And how do we deal with it. Do we need to get someone in to replaster again? We are having a solid fuel fireplace put in and I don't want the heat to just cause it to do this again!

Any help would be much appreciated!! Thank you!!

 

[stevie2]

Hi,
I'm new to this forum and have looked over old posts but can't find anything that really answers my problem...
I live in a mid-terraced 1930/40s house - only moved in a year ago and have been working our way around DIY projects since. The problem is in our living room. When we stripped our wallpaper in October/November time all the plaster came off and what didn't was blown so we had some workmen in who replastered the entire room. We are just coming to have our fireplace sorted out (eventually!) and have noticed that the plaster on the chimney breast is blown again.
I could be quite accepting of this but as I paid over £300 only 5 months ago I'm not very impressed and don't really want to hear the words replaster!!
The plaster has got hairline cracks about a footish above the fireplace opening and they go up by about a foot as well. I've done the old tapping trick and its definately hollow sounding! The chimney breast is on an internal wall.

I really want advice on why this has happened so soon? And how do we deal with it. Do we need to get someone in to replaster again? We are having a solid fuel fireplace put in and I don't want the heat to just cause it to do this again!

Any help would be much appreciated!! Thank you!!

where ever it sounds hollow it needs taking off to brickwork and redoin again did this get done the last time or was it just reskim

 

[Richard C]

If it sounds hollow, it’s blown & the only cure is to take it of & start again I’m afraid but it may be easy to tell you why it happened if you can answer a couple of questions in addition to stevie2's question;
Do you know what base & finish coats were used by the plasterer’s, i.e. Gypsum base or finish plaster, sand/cement render base etc ?
Have you been using the fire since the breast was replastered?

 

[CazB87]

No it wasn't taken back to brickwork - the blown plaster was knocked off mostly by myself and my partner and then they just reskimmed as far as I'm aware.
I also don't know what they used which i guess isn't very helpful!
The chimney hasn't been used to date as we haven't had to chance to get it finished off and are just about to. Will this cause the plaster to crack more? We have since noticed that the plaster appears to have blown in other places around the room as they also sound hollow.

 

[Richard C]

The reason for my questions was that Gypsum plaster doesn’t like heat much above 50 degrees C & the wall/chimney breast in the area immediately around a fire or stove can reach temperatures well into the 90’s; this heat causes Gypsum plaster to crack & fail.

In your case, as you haven’t used the fire, something else seems to have gone wrong. It’s probably down to poor preparation prior to skimming & if the base coat was also blown, the affected areas should have been removed back to brick/block, new base coat applied & then re-skimmed. If it’s just the new skim coat that’s blown, it’s time to call your plasterer back if you can as there is not much you can do with it apart from removing & starting again. Do bear in mind what I’ve said about using Gypsum plaster around a fire/stove, you need to use heat proof base (sand/cement/lime render) & heat proof finish plaster such as this;
http://shop.vitcas.com/vitcas-heat-resistant-plaster-16-p.asp

Here’s a link to an archive thread on the subject;
//www.diynot.com/forums/viewtopic.php?t=211524

 

[CazB87]

Thank you very much for your help - I think we are going to call him and ask him to come and look at it because I'm not happy to leave it as is! Thanks again!

 

[TheJay]

What plaster should be used for base and second coat on a fireplace chimney breast?

 

[Alastairreid]

Sand and cement and multi finish.

 

[TheJay]

Thanks for the reply, just regular red builders sand? Multi finish like this http://www.amazon.co.uk/dp/B00D1D8H...UTF8&colid=7LMVQY0HCKJI&coliid=I1R4U30CKJMS2Z ? Smooth with regular square edged plasterers trowel?

 

[Alastairreid]

Thats filler!


Use plastering sand and portland cement from your local builders merchants mix with a dash of waterproofer/plasticiser through the mix.

Dampen the wall down before you start.