How to remove Gypsum Plaster from solid brick wall? for internal wall insulation with wood fiber and lime plaster

[WhiskeyTangoFoxtrot]

Hi

We're in the process of adding internal wood fiber insulation to our property, to make the walls breathable again. We removed all the plaster from the walls and are planning to plaster it back with insulating lime plaster to 30-40 mm depth and then wood fiber on top and lime green solo plaster on top.

We're planning on using this system from Ecological Building Systems

but we're running into problems where the gypsum plaster has been stuck directly to the bricks (see picture below) and is not completely coming off and is leaving a layer of gypsum on the bricks. Does anyone have a solution on taking gypsum off completely from the bricks without damaging the bricks?

I'm out of ideas and only solution is to sand it down to the bricks.

Any help will be greatly appreciated

Thanks!

 

[Deleted member 174758]

Needle scaler or a small breaker with a scraper blade. I have seen chemical poultices used to remove multiple layers of lime wash from stone carvings, so whilst expensive it might work if you mechanically remove enough lime plaster. TBH internal skin brickwork in old buildings is often very poor quality (it was going to be plastered so why do your best work?), so be prepared for disappointment

Edit: scraper here. Also on Amazon

Less dusty than grinder.wheels by far

 

[cdbe]

I have a thing like this, never used it, bought it because it looked useful - might be worth a try, obviously PPE up for the dust.

 

[JohnD]

You can scrape plaster off the walls with a spade, though similar scrapers are made. It does not matter if the bricks get scratched. A wire brush will remove remnants.

You will need mask, hat, goggles, overalls and a lot of rubble sacks.

 

[WhiskeyTangoFoxtrot]

Haha I’ve been doing it with a hammer and chisel and so far has been easy because lime plaster was coming off easy.

I’ve got hold of a Sds drill and using the hammer function with a chisel bit to take off the gypsum but I cannot take it all off as I mentioned as it’s just making a powder from the gypsum plaster

thanks For the comments so far I’ll try them out!

 

[JohnD]

Try a spade.

 

[cdbe]

Try a spade.

Nothing more satisfying that "spadeing" a load of old plaster off a wall!

 

[Deleted member 174758]

I’ve got hold of a Sds drill and using the hammer function with a chisel bit to take off the gypsum but I cannot take it all off as I mentioned as it’s just making a powder from the gypsum plaster

There is a considerable difference between using a thick, blunt, forged SDS chisel and using a thin scraper blade, which is more like a spade or a very large wood chisel. The spade mentioned will indeed take loose lime plasterwork off a wall, but if it is still well adhered you may well find that the spade doesn't work - the scraper does work in that case. This is thecsort of job where one tool alone may not deliver a solution

 

[redmirror128]

I have almost exactly the same problem – except my walls are solid concrete. I can get the main layer of gypsum plaster off, but the last bits are really tricky, particularly where it is filling gaps. What worked in the end for you?