Stage 1 of your damp cure - establish the construction
When investigating damp, the most important thing to do, is to work out what your house was built of, along with how and when.
English houses and cottages vary tremendously in construction. What they are built of and how the materials were used, varied by
- how much money was available for the work,
- the skill and experience of the builder,
- and who they were trying to impress!
The construction is often complicated by extensions, facings, and other alterations carried out by successive owners.
Why is this information important? Because this determines
- how the house behaves,
- what problems it can suffer from,
- how problems and decay affect it,
- and what it needs to function correctly.
Many old houses are not what they seem
Finding this out can be difficult - many houses are not what they seem! A lot of houses had brick facings added in Georgian and Victorian times. What looks like a normal brick cottage, may be something totally different! To find out, I have to check wall thickness’s, check how the bricks are laid, listen to what the walls sound like when thumped/tapped inside and out, check any hidden bits of wall in the loft/under stairs/etc. and, where possible, see what they look like when viewed with a thermal imaging camera.
I am no longer surprised at what I discover, but a lot of owners are!
The cottage my own mother lives in, looks for all the world like a late Victorian 2-storey brick house with thicker walls downstairs. When I investigated though, I discovered it was originally a single-storey flint cottage that had been bricked round and extended upwards in Victorian times.
When I investigated an 1850s rectory, the owner was able to produce the original architect's drawings and the written specifications for the builder, so she knew with absolute certainty that it was a brick building from the 1850s. The specification stipulated that the existing timber framed Tudor house had to be demolished, and sold to part fund the building work. I found numerous anomalies when checking the walls, and my thermal imaging camera revealed a large part of the Tudor house had survived. The builder had just encased the timber frame in new brickwork - contrary to the plans and specification!
One of the more unusual discoveries was on an 18th century brick and flint farmhouse. It had been extended both upwards and lengthways over the centuries, with the part closest the road having a Victorian brick facing over the flint walls. This wasn't what was unusual. The unexpected discovery was the gabled flint wall at the other end of the house. This turned out to have a 19th century flint facing on an 18th century flint wall! You may say, unusual, yes but surely important, no? After all, it's all just flint? In fact, this was very important. The flint facing had been treated like a modern cavity wall and pointed with a cement mortar that was making the wall damp. 19th century flint facings are rarely well bonded to the backing wall and damp can wash away the mortar holding them to the backing so they spontaneously fall away. If the wall had been a solid flint wall, like the builder had assumed, this threat would not be present.
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