We use our knowledge of traditional construction and materials, and of the materials used for repairs and alterations in the twentieth century. We also understand the behavior of water as a liquid and as a vapour, and the importance of ventilation and heating. We try not to jump to conclusions until we have considered all the possibilities and have found the cause of the defect, rather than just treating the symptoms. We recommend and specify lime mortars, plasters limewashes and other breathable materials for repairs, and natural insulation materials for improving the energy performance of buildings.
We understand the limitations of so-called ‘damp meters’ and use an ever-growing collection of equipment to supplement our observations during surveys and investigations. It includes a thermo hygrometer to measure absolute and relative humidity, an infra red thermometer, a thermal imaging camera, a boroscope, and camera poles to take high-level photographs. We also have an electrical resistance meter, which we can use to take comparative readings on timber.
Our carbide meter is little-used because of the time that it takes to measure a sample and the need to drill holes in walls, but it is the most accurate way of getting moisture readings on site and can be invaluable in some situations.
This solid stone rubble wall was re-pointed with lime and lime plastered. The workmanship was good, but a regular pattern of damp patches appeared in winter. We discoverfed that these corresponded with the positions of through-stones. The wall was exposed to driving rain and the through-stones allowed water to pass through to the inside. We recommended adding a lime render and limewash to protect the wall.
This large Victorian house was extensively renovated about twenty years ago. Its lowest storey was originally used for service accommodation. As part of the renovations the lime plaster was replaced with a waterproof sand and cement finished with a thin layer of plaster. Damp is now breaking through in places. The client was considering reinstating lime plaster, but we suggested a cautious approach to this, as there are now concrete floors, the external ground level is close to the ceiling height, and there is an expectation of a blemish-free finish for its current use.
Thie maintenance of chimneys is often neglected. The owners of this house were only aware of the multiple problems visible here when we carried out an inspection.
In this case the cause of a damp problem was obvious but sometimes problems caused by leaking drains, high ground levels and overflowing gutters are less obvious and can be mistaken for rising damp.
enquiries@jwrc.co.uk
0330 133 2865