Hello,
we have an old house that is about 300 years old, with exterior walls approximately 60 cm (24 inches) thick.
We recently purchased a moisture meter and found that one exterior wall, up to a height of about 120 cm (47 inches), shows a reading of “100.” In these areas, the plaster also feels hollow underneath and will likely start to crumble over time.
The other exterior walls have readings between 70 and 80.
Around the outside of the house, we have noticed a concrete ring approximately 50 cm (20 inches) wide. This does not appear to be connected to the foundation slab, and in the gap between the slab and this base, we can see some black sealing material protruding slightly. Could it be that the previous owner installed some sort of drainage system there?
The house was unoccupied for more than 10 years, and therefore it was not regularly heated during that time. It used to be an old mill and is otherwise in good condition. In 2003, there was a flood with water reaching about 50 cm (20 inches) inside the house. Is it possible that since then it has never properly dried out?
Under these circumstances, how should or could we achieve stability regarding moisture? Or is it likely that for such an old house in a flood-prone area, this will never fully work?
I need your advice.
Thank you
we have an old house that is about 300 years old, with exterior walls approximately 60 cm (24 inches) thick.
We recently purchased a moisture meter and found that one exterior wall, up to a height of about 120 cm (47 inches), shows a reading of “100.” In these areas, the plaster also feels hollow underneath and will likely start to crumble over time.
The other exterior walls have readings between 70 and 80.
Around the outside of the house, we have noticed a concrete ring approximately 50 cm (20 inches) wide. This does not appear to be connected to the foundation slab, and in the gap between the slab and this base, we can see some black sealing material protruding slightly. Could it be that the previous owner installed some sort of drainage system there?
The house was unoccupied for more than 10 years, and therefore it was not regularly heated during that time. It used to be an old mill and is otherwise in good condition. In 2003, there was a flood with water reaching about 50 cm (20 inches) inside the house. Is it possible that since then it has never properly dried out?
Under these circumstances, how should or could we achieve stability regarding moisture? Or is it likely that for such an old house in a flood-prone area, this will never fully work?
I need your advice.
Thank you
M
mazzo041224 Mar 2019 08:54Unfortunately not.
The moisture has risen up the walls to nearly 2 meters (6.5 feet) high.
I believe that walls made of rubble stone should not be plastered at all, but left as exposed stone walls. The stones themselves don’t absorb water, only the mortar joints and the plaster do...
So, remove the old plaster, dry the walls using large infrared heating panels, and then keep the rooms gently heated.
However, with such thick walls, there is probably no reliable method to keep them dry, like a horizontal damp-proof course or something similar.
But maybe I’m wrong?
The moisture has risen up the walls to nearly 2 meters (6.5 feet) high.
I believe that walls made of rubble stone should not be plastered at all, but left as exposed stone walls. The stones themselves don’t absorb water, only the mortar joints and the plaster do...
So, remove the old plaster, dry the walls using large infrared heating panels, and then keep the rooms gently heated.
However, with such thick walls, there is probably no reliable method to keep them dry, like a horizontal damp-proof course or something similar.
But maybe I’m wrong?
No, you are correct. Such old masonry is never truly dry by nature.
A few years ago, an architect explained this to us. I am a churchwarden, and we were frustrated that the interior plaster of our 800-year-old church kept flaking off. He basically said that the saying “a house needs to breathe” is usually nonsense, but for buildings this old, it actually holds true. Built from brick, which is very porous, with fieldstone boulders and shell limestone mortar completely without cement, the building absorbs moisture from the surrounding air. When, as we did, you apply cement-based plaster inside like you would in any modern construction and then paint it with a synthetic paint, you create a barrier inside. The old masonry rejects this barrier, and the moisture causes the plaster to detach.
Under his guidance, we then had the walls stripped of the old cement plaster, applied a hydraulic lime restoration plaster such as a trass-based repair render, and had the walls painted with lime paint from Keim. In addition, the ground around the building was adjusted to slope away from the house, and lo and behold, the plaster now holds. The walls feel slightly damp but it is not uncomfortable to be inside the building.
Karsten
A few years ago, an architect explained this to us. I am a churchwarden, and we were frustrated that the interior plaster of our 800-year-old church kept flaking off. He basically said that the saying “a house needs to breathe” is usually nonsense, but for buildings this old, it actually holds true. Built from brick, which is very porous, with fieldstone boulders and shell limestone mortar completely without cement, the building absorbs moisture from the surrounding air. When, as we did, you apply cement-based plaster inside like you would in any modern construction and then paint it with a synthetic paint, you create a barrier inside. The old masonry rejects this barrier, and the moisture causes the plaster to detach.
Under his guidance, we then had the walls stripped of the old cement plaster, applied a hydraulic lime restoration plaster such as a trass-based repair render, and had the walls painted with lime paint from Keim. In addition, the ground around the building was adjusted to slope away from the house, and lo and behold, the plaster now holds. The walls feel slightly damp but it is not uncomfortable to be inside the building.
Karsten
W
wurmwichtel25 Mar 2019 11:26Well, living in something like that means accepting uncomfortable indoor climate or investing a lot of money. The description of the "uncomfortable climate" shows a lack of knowledge.
There are many methods to dry such masonry and consequently the floor as well. Horizontal and vertical waterproofing techniques, injections, drainage systems...
This should be assessed by a professional.
You can easily spend 50,000-100,000 (currency) on something like that. Please explain why the house has stood for 300 years and other buildings have existed since the 14th century.
Walls used to be somewhat damp — that was normal and because of drafty windows and the associated air exchange, it generally was not a problem.
My parents-in-law live in an old parsonage from the late 19th century. It was built using various materials, ranging from facing bricks to large boulders in the basement walls. Fifteen years ago, the exterior walls were also mostly damp after the house had been vacant for a long time (but it was not flooded). The walls are about 60 cm (24 inches) thick.
The renovation was carried out using cement-free lime plaster, new windows were installed, and the surrounding ground was slightly lowered to maintain a slope away from the house. However, no additional drainage system was installed. On the windward side, the wall at the basement level remained damp even after the renovation. Later, a baseboard heating system was installed, and a ventilated facade was added as well. Now, there are no issues, the indoor climate in the house is very comfortable, but the heating costs are quite high – which is not surprising given that the house is very large with high ceilings, reflecting its original use.
The renovation was carried out using cement-free lime plaster, new windows were installed, and the surrounding ground was slightly lowered to maintain a slope away from the house. However, no additional drainage system was installed. On the windward side, the wall at the basement level remained damp even after the renovation. Later, a baseboard heating system was installed, and a ventilated facade was added as well. Now, there are no issues, the indoor climate in the house is very comfortable, but the heating costs are quite high – which is not surprising given that the house is very large with high ceilings, reflecting its original use.
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