[Strawbale]lime and earth plaster

[Stewart Hargrave]

On 30 Sep 2004 at 14:11, j-verzijl at dbafm... wrote:

> Hello,
> 
> This question is not exactly relating to bales bud it does to lime and
> earth plaster.
> 
> We are renovating an old house and have plastered our walls with earth
> plaster. Most of the walls contain tubes witch are connected to our
> central heating system. The walls itself are made of f brick as is the
> foundation. We have a lot of moist climbing up from the walls and some
> areas won't dry. There seems to develop some white powdery fungus on the
> lower part of some inner walls. We thought about stripping the lower part
> of the wall and use a lime plaster instead. Would this solve our problem?

I'm not an expert in earth plasters, but I do have experience working in property 
maintenance. 

At the risk of getting off topic, I would suggest that you have what we in the UK call 
Rising Damp (assuming there are no leaking pipes). Moisture is being absorbed from 
the ground, and is soaking into the wall like a sponge. 

Usually, you need to have some sort of Damp Proof Course installed. This is some form 
of horizontal barrier in the wall, just above ground level, to stop the progress of the 
moisture. It can take various forms, and is something you need expert advice on, 
possibly from a building engineer, or specialist company. 

Once cured, be prepared for the wall to take several months to dry out fully. Another 
method may be to 'tank' the walls. This would involve removing all the surface covering 
back to the brick, and then coating with bitumen before recovering. This is not allways 
appropriate, often less satisfactory, and does not address the cause of the problem. 

I did hear recently of a titanium wire DPC, which somehow uses a small flow of 
electricity to repell the moisture, but I don't know much more about it.

This page may give you some more pointers: http://tinyurl.com/5wtm4

The white powder may not be mould, but could be efflouresence - this is the result of 
mineral salts in the masonary being carried to the surface by the water, usually forming 
a fluffy white deposite. It can make the surface of the wall hygroscopic, which means it 
will attract moisture. This can mean that even when the wall has fully dried out, the 
surface can remain damp. The only effective cure for this is stripping off the old plaster 
and re-plastering. However, this would be pointless until you have cured the underlying 
problem.  


-- 
Stewart H.