Seasonal stress: Resisting the effects of extreme weather

Robert Hamilton on how you can prevent weather damage to period properties

"The last winter was freezing, and the summer that followed was hotter than ever. Should I worry about the property damage these successive extremes can cause?"

It has been interesting to see the effect the recent very hot dry weather has had on some of our local buildings. Roofs have become slightly dished, walls have cracked, window frames have shrunk in their openings, plastic gutters have crept…are these going to cause problems next winter? Even worse, has the very hot summer following almost on the heels of an extremely cold snap caused irreparable damage to buildings?

Briefly, the answer is no. These weather extremes are a small incident in the life of a building already two hundred or more years old – think back to 1976, when the drought was worse than we have just experienced. However, good maintenance is the key to preventing quirks from becoming problems.

Dishing of roofs happens because the underlying wooden rafters have shrunk from drying out of their normal level of humidity. They will recover to some extent when the wet weather comes. However, there is a risk that this will cause the fixings of the stone slates, tiles or slates to loosen and so pre-winter input is strongly advised to repair. Lead or copper ‘tingles’ are a cheap and easy remedy to strap slates and tiles back into place and will hold for some twenty years when applied correctly.

Cracking to walls is likely to close up again when the stone or soil regains its natural water content, but re-pointing may be necessary to replace damaged mortar which can otherwise become an access for penetrating dampness. Remember to match your mortar for both colour and lime content, as modern cement mortars can cause damage to limestone. More severe cracks in door or window lintels can be the result of ground shrinkage and/or constant sunshine and may require more drastic work such as replacement.

Wooden window frames may also have shrunk like the wooden rafters, or the fixings may have become warped. Again, filling around the frames with plastic wood or similar, or if there are distinct draughts consider secondary glazing which is permitted in Listed buildings and is highly effective as an insulation method.

Plastic gutters will expand and contract under the influence of heat and cold and will also become brittle. Joints will slip and weed growth will flourish when all else is dried out! An inexpensive remedy is to readjust and to add a small brass or stainless steel screw to secure the gutter channel to the supporting clip. In this country, the majority of builders use supporting brackets/clips at one-metre intervals, whereas in several European countries such as France, Germany and Switzerland the brackets are at half-metre intervals with additional support either side of joints in the channel. Ideally, I recommend that plastic guttering is replaced with more durable materials such as aluminium, which is acceptable for Listed buildings, or copper.

Whoever would think that we should be grateful for our normal temperate and damp climate!

Central Surveying has offices in the Cotswolds and Knightsbridge, specialising in independent professional surveying and property consultancy services for commercial and residential clients in the Cotswolds, South West and London. Robert Hamilton works from Naunton in the heart of the North Cotswolds. To contact Robert, telephone 01285 640 840 or visit www.centralsurveying.co.uk.