| Condensation will occur on any surface that is below | | | | approximately one square foot for every 200 to 300 |
| the dew point of the air in contact with it (temperature | | | | square feet of ceiling area (not more than 50% |
| at which condensation will occur at the existing | | | | through the roof, and no less than 50% through the |
| humidity level). In most houses in winter, the inner | | | | gables or soffits).MOISTURE PRODUCED BY |
| surfaces of the windows are the coolest surfaces | | | | VARIOUS HOUSEHOLD |
| and condensation will usually occur there before it | | | | ACTIVITIES FOR A FAMILY OF FOURActivities |
| appears on other surfaces. It seldom appears on walls | | | | Moisture Produced (pounds) (litres) |
| because they are normally warmer, although | | | | Cooking 3 meals a day 2 1.0 litre |
| occasionally condensation may occur on cold spots | | | | Dishwashing 1 0.5 litre |
| such as nail heads and in the corners of outside walls | | | | Bathing |
| where the insulation is reduced, or in confined spaces | | | | - shower 5 2.5 litres |
| where the circulation of warm room air is restricted. In | | | | - tub 2 1.0 litre |
| some cases this can lead to mildew and the growth of | | | | Clothes washing (per week) 4 2.0 litres |
| mould.When condensation becomes excessive the | | | | Drying indoors or with unvented dryer (per week) 26 |
| moisture load must be decreased or the ventilation | | | | 13.0 litres |
| rate increased. To reduce the moisture load, humidfiers | | | | Floor mopping (per 100 sq.ft/) 3 1.5 litres |
| should be shut off, automatic dryers vented outdoors, | | | | Occupants (family of four per day) 12 6.0 |
| clothes drying indoors avoided, and the structure | | | | litresDehumidifiers, depending on the capacity of the |
| checked for other possible moisture sources | | | | model chosen, are typically capable of removing 7.5 to |
| (ventilation, insulation and moisture barriers in the attic, | | | | 20 litres of water from the air in the house, per 24 |
| basement or crawlspaces; open cisterns; seepage in | | | | hour day. The age, type and style of home will affect |
| the basement etc.)HANDY HINTThoroughly dry a | | | | the degree of moisture retention, and therefore have a |
| damp spot on an exposed foundation | | | | bearing on the size of dehumidifier required.Controlled |
| wall or floor with a hair dryer. Tape a 12 inch square | | | | air exchange, using an HRV (heat-recovery ventilator) |
| of | | | | is usually a requirement in newer homes, especially |
| heavy plastic over the spot, and check it in one or | | | | those built to R2000 standards. In these homes, |
| two | | | | uncontrolled infiltration/exfiltration of air is reduced to |
| days. Seepage will cause the underside of the plastic | | | | almost zero, and therefore moisture will quickly |
| to | | | | accumulate causing condensation on windows and |
| be wet, but condensation will form on the top | | | | other cool surfaces.Copyright Gil Strachan - All rights |
| side!Ventilation is generally the most effective means | | | | reserved.Gil Strachan is a professional home inspector, |
| available to the homeowner for reducing humidity and | | | | representing Electrospec Home Inspection Services in |
| should be obtained by opening windows or operating | | | | east-central Ontario, Canada since 1994. Visit to learn |
| an exhaust fan (or the furnace fan) as soon as | | | | more about home inspections."The Home Reference |
| significant window condensation appears.If only a | | | | Book" |
| moderate or minimal amount of condensation is | | | | You can probably find a home inspection for a little |
| experienced, switching the fan on a forced-air furnace | | | | less than what we ask, but you probably won't find the |
| to the "continuous" or "summer" setting can help | | | | Home Reference Book. A $60 value, this |
| reduce humidity in moist areas, by circulating and | | | | solutions-oriented reference tool comes free with |
| blending the air throughout the house.Attic ventilation is | | | | every inspection we perform.It's the first tool you |
| normally provided by vent openings totalling | | | | should have around the house! |