Common sense can cure condensation

Press, 9 July 1983, Page 12

Common sense can cure condensation

Home Line

with

Bill Harrison

Condensation is the main topic this month to help all of our readers who are desperate to solve the problems of windows, and even walls, dripping with water.

“My block walls are actually dripping with water,” “This is my first winter in Christchurch and I find my clothes are going mouldy in the wardrobe,” and, “How can I overcome the condensation and mildew in my bathdroom,” or “The wall in my daughter’s bedroom has mould on it, what can I do,” are typical of the many queries we have received. Condensation, insulation, ventilation are all closely related to mould and mildew. Condensation is as old as creation, one of the basic laws of nature. Without it there would be no rain. Insulation, has been used by sheep and other animals have used it to good effect for quite some time. Their woollen fleeces form a protective barrier between their warm bodies and the cold air around them, or the hot air if it is summer time.

Ventilation is a most important part of the design of any building, but something that is too often overlooked. I believe it was overlooked by the people who decided, as a result of the “energy shock” that it should be mandatory to insulate our houses.

Mildew, a primitive form of plant growth from

spores that are everywhere, needs continuous high levels of humidity to survive.

Condensation has always affected our houses. The older timbered homes, however, seemed to be less noticeably affected than today’s fully insulated, almost hermetically sealed houses.

The older house was invariably draughty, with sometimes more than one chimney, and this provided a good source of ventilation.

Our modern home probably has no chimney, and has aluminium framed win-

dows with sashes that are draught-proof when closed. Worst of all, the occupants are probably away all day and their home closed securely against intruders.

Ideal conditions for the growth of mould! It would be so easy to answer these queries by quoting straight from some of B.R.A.N.Z. excellent leaflets on the subject. But perhaps the points can best be made by some actual experiences. A wall in a new flat was so wet and mouldy that my builder colleague had to remove the interior wall

lining to prove to the owner that the damp and mould was not caused by a fault in the veneer, or leaking pipe or roof.

Investigation revealed that the occupier was a hair dresser who each evening washed the salon’s towels, and then dried them in the back bedroom.

Naturally, it was off to work next morning with the dry towels and the flat left securely locked, with the vapour laden air left to condensate on the coldest wall of the room. Then there was the carpenter who built a pair of

flats, sold one and lived in the other. He was at this wit’s end when he told me his story of how his flat was dripping with water while the other had no problem at all.

The difference in lifestyle of the occupants was the answer to some of the problem. The carpenter and his wife went off to work each day leaving their fiat securely locked, while their neighbour stayed home with windows open and perhaps a heater on. The golden rule of all things in moderation will help. Have a little continuous ventilation. and even levels of heating to keep the house warm. Avoid excessive moisture in the home by installing a vent to remove cooking and bathroom steam. Your condensation problem can probably be cured by applying one or more of these techniques: ® Windows can now be double glazed, or have condensation channels fitted to divert water from damaging furnishings. Double spurred window catches that hold the sash open slightly can be fitted. ® It is no longer impossible to insulate existing walls or ceilings. © Plastic film can be laid under wooden sub-floors to prevent rising damp. ® Extractor fans for bathrooms and rangehoods for kitchens remove excess steam.

© Thermostatically controlled heating systems provide continuous warmth. © Fungicides that can be added to paints and pastes to resist mould (flour pastes should be avoided). B.R.A.N.Z. Information Bulletin 216, and Leaflet 783 “Condensation and Mildew in Homes” provide just some of the informative reading that is available on this subject from the Building Research Association of New Zealand, Private Bag Porirua, or the Building Centre in Cashel Street. If you have a question relevant to home-ownership or maintenance for this monthly column, write to “Home-line,” c/o The Building Centre, P.O. Box 22143, Christchurch. A nom-de-plume may be used, but the writer’s name and address must be included.