Use of lime plaster.

[Bayliss]

I seem to be asking questions but offer no advise to other forum users = novice

Our cottage is a mish mash of building materials where others have 'contributed' to its maintenance upkeep over the decades. One of the gable walls is now solid 9 inch brick up to first floor level thereafter retains its original timber and plaster work to roof level. Where the brickwork has been laid no damp course has been inserted and we have dampness coming through the weak cement based plaster. In fact the plaster has blown to a height of about two feet. My intention is to hack off the old plaster and replace with lime plaster in the thought that this material will allow damp to penetrate and evaporate naturally. Any advise / comment welcomed.

 

[robgil]

Why not just put a chemical dpc in there instead? What kind of bricks are they , are they old? Any photos would really help.Are the timbers are still dry?

Sometimes using modern building techniques and materials is a good thing if it works and helps preserve the original fabric of the building.

 

[Pford75]

I personally wouldn't go the injected DPC route - I've seen them fail in several friends houses (plus you will have to replaster anyway).

I would...

Remove the cement based plaster
Allow the area to dry out
Replaster in lime
Use a breathable finish on the lime plaster (limewash, distemper etc.)

 

[MdB]

Again no for the injected DPC.

I would first identify as best you can the reason for the high moisture content in your walls, looking in particular at high outside ground levels / water being discharged into the ground nearby etc. The more you can reduce the water table, the less moisture you will have that needs to evaporate internally. Then as Pford75 suggests.

 

[MatthewC]

I agree with the above; you just have to sort the actual causes of damp (not the symptoms) and let the whole place dry out. We have just lowered the ground levels around our house as the old level was six inches above the floor level in the kitchen, and largely concreted up to the walls. The digger tracks are the old level, and the new level will be the top of the outer blocks. Expensive and drastic, but worth it in the long run.

More pictures at http://houseintheenchantedforest.blogspot.com/

Matthew

 

[Bayliss]

Thank you all for responses, the brickwork has taken the place of what was previously timber frame / lathe and plaster. This work most likely done over 70 years ago. The internal wall is plastered with I suspect a cement based plaster in very weak mix, as I have said its now blown. The ground height outside is below the brick breathers and I think that is acceptable. I can buy some lime putty locally but would appreciate advise on mix content and what are best products. Thank you.

 

[robgil]

Do you have any idea at all where the moisture may be coming from? You say it is a gable wall, is it exposed? Does the damp get worse when it rains? Are there any signs of water running down the wall at all?
Or , do you just live on the water table? It has been pretty dry here lately and I dont live too far away from Eye.

 

[Bayliss]

The damp is of the rising type, it was there when we moved in and slowly crept up the wall to present height of about two feet. I should have sorted it seven years back when we moved in Certainly no rain penetration or any evidence of a natural spring or such like although we do seem to have a locally high water table. The blown plaster is currently dry and very crumbly and I suspect that the water is now already evaporating through this 'apple crumble' like material!