Ok time for an honest update; the clay plaster is delaminating from the wall as it dries and shrinks. Huge sections sound totally “blown” / hollow when tapping on them, and they are actually wiggling when you press on them.
The issue is due to our following mistakes:
1. Trying to apply this stuff to very flat modern block walls which have very little mechanical key. I did key / chew the walls up with an SDS, but it obviously wasn’t enough
2. Adding too much water to the mix, resulting in too much shrinkage with drying
3. Choosing to use clay instead of lime as the primary binder. The clay of course doesn’t really form a chemical bond with the substrate in the same way as lime
4. Applying all 4 CM thick in a single pass. Inside our main house we’ve always done 2 passes of 2 cm thick each
I’m absolutely convinced of the value of activated charcoal itself as an insulating aggregate. It’s properties are ideal for that application. However our other mistakes have sabotaged the charcoal component of the experiment and have made this experiment a distinct FAILURE.
I’ll likely be stripping it all off and replacing it with a typical wood-wool boarding system with a lime backing coat and lime skim coat and limewash paint.
It is what it is. Like always, I’ll take my ass-beatings and move on more enlightened than before.
The issue is due to our following mistakes:
1. Trying to apply this stuff to very flat modern block walls which have very little mechanical key. I did key / chew the walls up with an SDS, but it obviously wasn’t enough
2. Adding too much water to the mix, resulting in too much shrinkage with drying
3. Choosing to use clay instead of lime as the primary binder. The clay of course doesn’t really form a chemical bond with the substrate in the same way as lime
4. Applying all 4 CM thick in a single pass. Inside our main house we’ve always done 2 passes of 2 cm thick each
I’m absolutely convinced of the value of activated charcoal itself as an insulating aggregate. It’s properties are ideal for that application. However our other mistakes have sabotaged the charcoal component of the experiment and have made this experiment a distinct FAILURE.
I’ll likely be stripping it all off and replacing it with a typical wood-wool boarding system with a lime backing coat and lime skim coat and limewash paint.
It is what it is. Like always, I’ll take my ass-beatings and move on more enlightened than before.
