I am going to talk a little on the subject of damp in old houses. I shall focus on one case which I came across recently which was a cellar in a 17th century house.
On inspection the walls were a mixture of brick and flint which had been painted over with what looked like a lime wash with layers of modern paint. The floor was modern cement over plastic sheeting. There was one air brick which was clogged up with leaves and debris off the street. There was a small window which did not open.
There was no ventilation, the dampness from the ground had been sealed by the plastic membrane and cement so it had risen up the walls which were sopping wet. What had meant to keep the cellar dry had actually made it worse. The picture above shows a small area of how it was – note the blue plastic sheeting sticking out beneath the cement. The timber in that picture was also sodden – in fact rotten where it went into the walls at each end.
This image shows the steps down to the cellar before renovation, the cement floor with plastic sheeting and note the green mould on the wall.
This image shows the brick walls before renovation, as previously described covered in a combination of lime wash and modern vinyl paint.
The cellar was too damp to have any use and the owner wanted to turn the front area into a laundry room whilst the back area into a larder and wine cellar. This was ideal as the back area was north facing and therefore cooler than the area at the front of the house.
There could have been two choices if the house had not been listed but it was Grade II listed and therefore having checked with Listed Building officers tanking the walls was not an option. I believe the better option was what we did. The concrete floor was broken up and removed and the plastic sheeting also removed revealing the chalky floor beneath. By doing this a workable ceiling height was gained A layer of sand went down over the chalk and heritage bricks were laid onto to. Instead of grouting the joins, lime was sprinkled liberally over the bricks and simply brushed into the joins with a soft brush. A simple and breathable and above all aesthetically correct floor created.
The paint and plaster was removed from the walls with a soft wire brush revealing a very attractive mix of bricks and flint stones. A french sink was plumbed into the front room along with the washing machine and work surface tiled with slate tiles. A new air brick replaced the old one and the small window made to open to allow much needed ventilation.
The stairwell was very restricting and too narrow to accommodate a conventional staircase. The best option was to build a ‘paddle’ staircase. It looks treacherous but infact works very well and reassuringly easy to use.
The area was turned into a usable and useful space. By removing modern materials and using breathable materials + adding ventilation, the dampness slowly but surely evaporated and as long as it is well ventilated the area has turned into a usable and useful space.
The key is is quite simple. Use modern materials for modern buildings and old breathable materials for old buildings. If you mix old with new and visa versa, problems with damp will arise.