Mold in the loft

Old 01-23-09, 02:05 PM
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Join Date: Jan 2009
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Mold in the loft

We've had a problem with our new house ever since we moved in - namely mold in the chipboard against the roof area in the loft.

Last year the builders sprayed it and discovered the vent for steam from the bathroom had been plugged straight into the attic rather than outside. This year the mold is back and boards have began warping and turning black as it did for two other neighbours on our corner last year (One seems to have had his sorted but the woman next door has had mold return to her attic too).

Do we need more vents put in the brickwork etc. or is there some other solution available? (The had to slit the central ridge as that hadn't been done either but this obviously didn't sort the problem last year and more needs to be done, to stop it going on indefinitely).
Old 01-23-09, 02:27 PM
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Mold/mildew will continue to return if affected surfaces have not been cleaned and disinfected. Mold/mildew will continue to return if underlying issues are not addressed.

Attics require adequate insulation and ventilation. Warm, humid air rises from heated area below. The goal is to retard as much of this as possible from entering the attic. Seal all gaps around perimeter and vents, chimneys, lights, etc. Make sure there is a vapor retarder under insulation. If batt insulation was used, the faced side faces down toward heated area below and serves as vapor retarder.

If there is not enough insulation, then more needs to be added. This can be blown in, loose fill, or additional unfaced batts (no additional vapor retarder). There are online calculators that will provide recommended minimum insulation for your ZIP. You can also call the local building code office to learn what the minimum R-value is recommended for your area. Keep in mind that this is the minimum.

Additional ventilation can be installed. Ridge vent with soffit vents tends to be the most popular. And, adequate number of soffit vents for intake air should be installed. Attic temp should be same as outdoors. The warm, humid air needs to escape. Ventilation intake and output should be equal. There are online calculators to help calculate the amount of required ventilation for your attic space.

If attic is not adequately ventilated with intake and output vents, when warm, humid air from below enters the cold attic space, it will condense on the underside of the roof. Then, you have problems with mold, mildew. Condensation can freeze and form icicles. When it melts, the water falls to the insulation. Wet insulation loses its insulative qualities.

ESB: Research Exposes Attic Ventilation Myth

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