Approximately 60% of houses in Wales are of a breathable stone construction with lime mortar. Constructed from local stone and lime the properties were designed to function as a “breathable” structure in their local environment.
Much of the original breathable external lime render and limewash has been removed and replaced with cement based renders and plastic paints. Internally the breathable lime plaster has been removed and”dry lined”or plastered over with “pink” non breathing gypsum plasters.
Modern renders and plasters are much harder than the lime based products they replaced and tend to crack and “blow” easily which leads to water ingress………so any water finding its way into a wall “wicks” through the wall and can’t escape until it finds a weakness in the internal plaster /mortar, causing a “damp patch”.
So what is the solution?
- take away the water source from the wall by checking all lead flashing, chimneys, roofs , facia, soffits and guttering
- (damp showing inside may not be directly related to the same external wall point)
- excavate and lay french drains
- remove the non breathable cement based render and/or plaster and allow to breathe
- replace with appropriately specified breathable lime based pointing, render or plaster
- paint the surfaces with breathable limewash or clay paints internally or limewash or breathable mineral paints/coatings externally
Walls will often dry out quickly once the failed cement render/plaster is removed and breathable lime based render/plaster applied.
This will give a long term solution to damp as your property can now breathe. The visual impact of the property will also be more aesthetically pleasing and the ambiance and feel of a room is much enhanced when using appropriate materials.
………………….Also lime mortars absorb 40 times more co2 than cement when carbonating……………………………