| Q: Gil, I think we have a mildew problem. It causes | | | | a hair dryer. Tape a 12 inch square of heavy plastic |
| problems for my daughter when she comes to visit ... | | | | over the spot, and check it in one or two days. |
| We think we may have to remove all the panelling and | | | | Seepage will cause the underside of the plastic to be |
| carpeting, apply something to kill the mildew on the | | | | wet, but condensation will form on the top side!Q: We |
| walls and floors and refinish the affected basement | | | | have a dehumidifier, but it is in the sump pump crawl |
| rooms. -Helen BatesA: It might not be necessary or | | | | space and probably doesn't do much good. If we turn |
| advantageous to tear up the whole basement at this | | | | it up very high, it just runs all the time. Maybe this is |
| point. At any rate, if you don't remove the conditions | | | | because it is pretty old, I'm not sure. It seemed to work |
| which are supporting the growth of mildew, you'll likely | | | | fine in our last house.A: The required size of |
| have a recurrance. It's somewhat difficult to speculate, | | | | dehumidifier will vary with conditions, and the size of |
| not having seen your home, but here are some things | | | | the house - but in any house with a severe humidity |
| to consider...Mould and mildew can occur in a house at | | | | problem such as yours, a new 60 pint (minimum size) |
| almost any time of the year, if the moisture content of | | | | dehumidifier with a drain hose directed to the sump or |
| the building materials is about 20 percent or greater. | | | | laundry drain should start to produce results. If you |
| High relative humidity, or saturation at or below grade, | | | | prefer to keep the crawl space closed, you'll likely |
| can create this condition.A good plan of attack begins | | | | need two machines.THE BOTTOM LINE: First things |
| with decreasing dampness and increasing ventilation. | | | | first - look for external sources of moisture, then |
| Maintain a negative grade slope away from the house; | | | | internal; and then study ventilation followed by |
| and ensure that evestroughing, down-spouts and | | | | dehumidification, and if necessary, insulation and/or |
| drains are free of debris, and properly directing water | | | | vapor barriers where required.A FEW QUESTIONS |
| at least two meters away from your foundation wall. | | | | FOR HELEN:1. How is your lot grading? (any slope |
| Even if your house is relatively new and has properly | | | | toward house?) Settlement around the perimeter of |
| installed, working footing drains, excessive surface | | | | the foundation?2. Downspouts and drains in place?3. |
| water can saturate the foundation wall, and evaporate | | | | What type of heating/ventilating systems do you |
| to the interior faster than it can be drained away. | | | | have? Same in basement?4. Is your kitchen range |
| Check to see if water pools anywhere beside the | | | | hood directed to the outdoors?5. Bathroom exhaust |
| house during a downpour or period of melting.Severe | | | | fans installed and used regularly? Vented through the |
| mould on inside wall and ceiling.Moisture problems can | | | | wall or roof (not into the attic, hopefully).6. Clothes |
| originate inside or outside the house, or both. In cooler | | | | dryer vent directed to the outdoors?7. Is ventilation |
| weather, condensation will occur on any surface that is | | | | provided for the basement?8. Are any windows |
| below the dew point of the air in contact with it | | | | sweating?9. How old is your house?10. Construction: |
| (temperature at which condensation will occur at the | | | | solid brick/brick veneer/siding etc.11. Are roof/ridge |
| existing humidity level). This moisture usually appears | | | | gable vents visible?Also, check the lowest course of |
| first on the inside surfaces of windows, and may also | | | | bricks for the presence of "weep holes" about every |
| appear around door jambs and where outside walls | | | | fourth mortar joint. (If your home is wood-framed with |
| meet the floor or ceiling. Closets can also become | | | | a brick facing, the mortar should be left out, to allow |
| damp due to reduced air circulation. In warm, humid | | | | any condensation between the exterior sheathing and |
| interior conditions, foundation walls may "sweat" | | | | the brickwork to escape to the outdoors.)Copyright Gil |
| profusely at any time of the year.Dehumidifiers can | | | | Strachan - All rights reserved.Gil Strachan is a |
| remove large amounts of moisture from the home, | | | | professional home inspector, representing Electrospec |
| and in summer, an air-conditioner is also a powerful | | | | Home Inspection Services in east-central Ontario, |
| dehumidifier;. Air conditioners however, consume | | | | Canada since 1994. Visit to learn more about home |
| considerable amounts of energy and may not be | | | | inspections."The Home Reference Book" |
| useful in spring and fall, when cooling is not | | | | You can probably find a home inspection for a little |
| required.Ventilation is an effective and inexpensive | | | | less than what we ask, but you probably won't find the |
| means available to you for reducing humidity, and can | | | | Home Reference Book. A $60 value, this |
| be obtained by opening windows or operating an | | | | solutions-oriented reference tool comes free with |
| exhaust fan as soon as significant window | | | | every inspection we perform.It's the first tool you |
| condensation appears.HANDY HINTThroroughly dry a | | | | should have around the house! |
| damp spot on an exposed foundation wall or floor with | | | | |