chimney breast removed what shall i use to repair the wall?

happyhero

Hi I had a builder in to advise me as to how to remove my chimney breast and have now done so but he warned me that I would need something to coat any remaining soot areas on the wall as it would come through any plaster etc. Well what I found was that, and I cannot imagine how they achieved it, that the inside of the chimney or bricks were rendered so that all soot was on the render. As i have removed the bricks this just left a streak of sooty render on the wall so I chiseled this off to leave clean brick everywhere so that i now have a clean brick wall to patch into the walls either side.

Do I now need to worry about soot, ie will it have done something to the bricks so that they still need some coating of something, they look totally clean?

I am going to build wardrobes in front so the wall will not be visible. Also I can plaster small areas pretty good but not a whole wall so I feel I could do a reasonable job of the plastering considering it will be hidden anyway but what should I use, plaster or render?

I am used to using the brown bonding plaster and then some finish plaster but I have never tried rendering, is it harder?

If render, I see there are different types of mix, what would I need?

Is this a simple plastering job on clean brick that I am making a mountain of?

Any advice help appreciated.

ILW

Is the flue supported?

macman

If it isn't, then the OP will have more coming through his ceilng than a few soot stains...

SailorSam

We had a chimney breast removed from one of the bedrooms must have been over 25yrs ago. The builder who who did the job was already in the house doing other work told us he could do it. I was up in the loft recently and notice the lintel he put in was just laid on the rafters and not doing anything.
It's stayed up all these years but i've got it on my 'to do' list this Spring.

dampdaveski

hapyhero,
assuming structurally sound and everything that should be is supported

Do NOT use browning or any gypsum based backing plaster it will fail, maybe not straight away but it will fail.
Clean down all the soot off the bricks even if it means using a hammer and chisel to remove the face of the bricks
apply an SBR/ cement slurry to the wall and render it with a 1 part cement and 3 parts cement render mix incorporating a waterproof additive.
soot = sulphate salts and sulphates salts on chimey breasts (or the old flue lines when they've been removed) can be incredibly difficult to treat correctly
aonther option is to use a cavity membrane system, which you can then use gypsum plaster on or dot and dab onto

If it is a ground floor chimney breast that has been removed then you have to consider the fact that next doors might still be in place and their flue might be full of rubble therefore you will have the effect of your damp proof course being bridged

If you've never done anything like this before, the risk of mr !!!! up visiting increases
I appreciate I sound a bit draconian but if it's not done right you will get yellow staining coming through your new plaster and decorations

good luck

happyhero

dampdaveski wrote: »

hapyhero,
assuming structurally sound and everything that should be is supported

Do NOT use browning or any gypsum based backing plaster it will fail, maybe not straight away but it will fail.
Clean down all the soot off the bricks even if it means using a hammer and chisel to remove the face of the bricks
apply an SBR/ cement slurry to the wall and render it with a 1 part cement and 3 parts cement render mix incorporating a waterproof additive.
soot = sulphate salts and sulphates salts on chimey breasts (or the old flue lines when they've been removed) can be incredibly difficult to treat correctly
aonther option is to use a cavity membrane system, which you can then use gypsum plaster on or dot and dab onto

If it is a ground floor chimney breast that has been removed then you have to consider the fact that next doors might still be in place and their flue might be full of rubble therefore you will have the effect of your damp proof course being bridged

If you've never done anything like this before, the risk of mr !!!! up visiting increases
I appreciate I sound a bit draconian but if it's not done right you will get yellow staining coming through your new plaster and decorations

good luck

Cheers dampdaveski for all that info, as i said above I have chiseled off the soot covered render so that whole area looks clean, so could anything still come through, or is clean, clean in this case?

I should explain more, we have an attic extension and when I remove the ground floor part as I have only removed the 1st floor part it will be all gone up to 1st floor ceiling level. The void between the 1st floor ceiling level and the attic floor is over 12 inches plus and this is where the last bit goes to the roof and it is supported on gallows and has ventilation into the void. This was done when I had the attic done in 2000 to allow me to remove the chimney breast in the future.

I know that most of the time now you are not allowed to use gallows now for this but must use a beam, but this job was under the watch of the local council and I suppose it must have been ok then as I was not aware of the support rules then and did not question it at that time the council saw it and passed it, together with the attic extension.

What will the SBR do?

Do I render and then use normal multi finish on top?

macman

SailorSam wrote: »

We had a chimney breast removed from one of the bedrooms must have been over 25yrs ago. The builder who who did the job was already in the house doing other work told us he could do it. I was up in the loft recently and notice the lintel he put in was just laid on the rafters and not doing anything.
It's stayed up all these years but i've got it on my 'to do' list this Spring.

And it could stay up many more years...or it could come down tomorrow. If so, it may well kill you or your family. Your ceiling joists are supporting many tons of masonry, which they were never designed to do.
As Clint said, 'do you feel lucky?'

dampdaveski

hi Happy,
SBR is basically a building adhesive / bonding / priming agent which is designed to make cement work better and create a stronger bond, i've found it is also good when used in this scenario to reduce the chance of sulphates leahing through. Don't confuse it with PVA as it is completely different
Normal multi finssh or board finish would be fine (it's what I use)

SailorSam,
macman does have a point!

Good luck!

happyhero

dampdaveski wrote: »

hapyhero,


apply an SBR/ cement slurry to the wall and render it with a 1 part cement and 3 parts cement render mix incorporating a waterproof additive.

More question please if thats ok, reading the SBR details it seems to say dont paint on more SBR slurry than you can render in 15minutes, so you render whilst the SBR mix is still wet, is that correct?

So if I cannot complete the area in 15 minutes, then I suppose I should have the mix beside my render and paint on as I can cope with the area, sound right or sound crazy?

Also if I am using Mastercrete cement, doesn't it contain plasticiser anyway so do I still need to add plasticiser or not?