Moisture management in crawl spaces: a bulwark against dry rot, the cancer of buildings

The crawl space is too often neglected by homeowners. However, it is a critical area where moisture easily accumulates and becomes the ideal breeding ground for dry rot ( Serpula lacrymans ), a dreaded fungus in the construction industry.

Why is the crawl space at risk?

A poorly ventilated or insufficiently protected crawl space against humidity creates an ideal microclimate for the development of dry rot:

• High humidity caused by insufficient ventilation, water infiltration or the absence of a floor membrane.

• Sensitive organic materials such as structural timber, directly exposed to stagnant moisture.

• Temperate temperature , often between 15°C and 25°C, which favors fungal growth.

The ravages of the weeping dry rot

Nicknamed the cancer of the building , dry rot attacks wood, degrading it until it is reduced to cubic dust. It progresses behind partitions, under floors and can remain invisible for years before its damage becomes apparent. Its development leads to:

• The progressive destruction of the structure (beams, joists, walls).

• Astronomical costs of decontamination and reconstruction .

• A significant loss of real estate value .

How can we prevent this scourge?

Humidity management is key:

1. Check the ventilation of the crawl space to ensure efficient air renewal.

2. Install a vapor barrier membrane on the floor to limit rising damp by capillarity.

3. Eliminate any water infiltration from poorly directed foundations, drains or gutters.

4. Maintain a relative humidity level below 60% using a suitable dehumidifier if necessary.

5. Regularly inspect critical areas to detect early signs of mold or dry rot.

In conclusion

Weeping dry rot is one of a building's worst enemies because, once established, it silently attacks the very foundations of the structure. Proper moisture management in the crawl space is not an option, but an absolute necessity to protect the health of your home and avoid repairs that can cost hundreds of thousands of dollars.

GEQ – Bâtiment Conseil reminds us that prevention is always less expensive than cure. A house protected against humidity is a house protected from dry rot.