Damp Survey and Damp Proofing in Winslow

The older properties around the Market Square, Horn Street and Sheep Street are typically solid-walled, in brick, local stone or render over rubble, with lime mortar and no original damp-proof course. Walls of this type rely on being able to dry outwards. The damp problems we see most often follow from something interrupting that: cement pointing or render on soft masonry, gypsum plaster and vinyl paints internally, ground levels raised by resurfaced paths and driveways, and rainwater discharging at the base of a wall. Where an injected course has been installed and damp has returned, the reason is usually one of those factors rather than a failure of the chemical itself.

Winslow sits on the clay of north Buckinghamshire, and clay behaves very differently from the sand a few miles east. It holds water against foundations in wet periods and shrinks in dry summers, and that seasonal movement opens fine cracks in render, pointing and around openings through which driven rain can enter. Properties with shallow foundations and mature trees or hedges close by are the most affected. Because the resulting damp appears and disappears with the seasons, timing is one of the most useful pieces of evidence we gather, and we always ask when the problem is at its worst.

The estates built on the edges of the town over the last two decades, and the further development that has accompanied the reopening of the railway line, are modern, well-insulated and comparatively airtight. Their moisture problems are almost always about air rather than fabric: humidity from cooking, showering and drying washing indoors, extract fans that are not used or not effective, and cold bridges at reveals and junctions where mould appears first. We measure humidity and surface temperatures rather than assuming, because the remedies for a condensation problem and for a fabric defect have nothing in common.

Timber inspection in the older part of Winslow concentrates on suspended ground floors whose sub-floor airflow has been reduced by extensions, conservatories or replacement solid floors, on joist ends bearing into damp solid walls, and on roof structures where thatch has been replaced or where long-standing leaks have gone unnoticed. Old flight holes from furniture beetle are very common in original softwood and usually represent activity that stopped many years ago. We look for live infestation, record moisture content and report whether any decay found affects structural members.