# Forum Home Renovation Rendering  Rendering / repairing Pise Walls?

## Tachyonics

Help please, does anybody have any suggestions / recommendations.  We live in a very old pise farm homestead & during the drought the walls have cracked in places - some cracks are fine and some are about 3mm thick in places.  The pise walls are just coated with layers of old paint.  So many products, so much unhelpful information from local hardware outlet!  Previous owners have coated some of the walls with gyprock but we want to keep the walls in their original state if possible.

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## watson

G'day mate,
We also live in a Rammed earth home, built in 1920.
So far, even though the drought has gone on for years, there are no cracks at all.
To give you some idea of the wall structure:
The footings are stacked slate shale......no mortar
Every foot high there are two strands of #8  barbed wire through the length of the wall.
The walls are a foot to 15 inches thick . (Old Bob wasn't too accurate with his set-up.) 
Where we have extended through the walls, I have not found a modern day product that adheres well to the old mud. Instead we have just used crushed up wall, mixed with water to fill gaps between the old (Wetted down first) and the new.  After 15 years there are no visible cracks.
Hope that gives you an idea.

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## watson

Added Details.
Our walls were rendered in Kalsomine, and as already stated old Bob wasn't too accurate, so in some areas the Kalsomine was just painted on, and at the top of the wall the Kalsomine was up to an inch thick. I don't think he owned a level or a plumb bob.
The Kalsomine was all removed, the walls scoured with a ten finger scraper, and re-rendered with sieved crushed up wall mud. When that was dry, we painted with two coats of Haymes Acrylic paint.
End of story...no cracks.

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## Black Cat

It is quite possible that the cracks will, to a large extent, close up once the soil has re-moistened around the building and the general humidity has increased. If not, then do what Watson says.  
As for 'render', the best treatment for old mud walls is either a slip of new mud, or whitewash. It will be as soft as the substrate you are applying it to, and will move with the building. The idea behind whitewash is that it is a 'sacrificial' layer that can wash off without losing the material from the wall. You just apply a new coat every now and then and all will be well. It also doesn't have to be white - you can add oxides for colours if you prefer something different. 
Don't whatever you do, get talked into using concrete render - it will accelerate the deterioration of the place as it is too hard and brittle and does not allow the walls to 'breathe' as they must to maintain the correct movement of moisture through the walls.

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