Damp is a silent enemy that moves slowly but surely to destroy your property, wreak havoc on your health, and make your home an open site for pests. It can appear immediately after flash flooding or it can be slow to emerge, sometimes taking years before becoming visible. The usual signs of dampness include, but are not limited to: musty odors, stains on ceilings and walls, mold and mildew, forming particularly in rooms with excess moisture such as kitchens and bathrooms, rotting wood in the structure of the house, and damp and moldy clothes and fabrics.

Once spotted, most homeowners start looking for a quick fix for their moisture problem, when there’s seldom a silver bullet for damp elimination. Treating moisture problems depends primarily on the type of damp affecting your home (because yes, there is more than one) and should be carried out only after detecting the source of the problem.

Let’s explore the three most common types of damp inside a structure and the recommended treatment for each.

Damp Types and Solutions

Condensation

The most common type of damp, condensation takes place when large quantities of water vapor are trapped inside a structure. When moist air from general everyday living comes into contact with cooler air vapors or surfaces, it cools down and can no longer retain the same quantity of water vapor, releasing the excess and forming dampness or water droplets.

Condensation is worsened by poor ventilation and intermittent heating, as this allows warm air to condense. It’s most likely to appear around doors and window openings, on colder areas of the walls, and where ceilings and floors meet with exterior walls. Common signs include puddles on window sills, damp patches, black mildew, peeling wallpaper, and water running down walls. If condensation happens constantly in the same place, it can lead to the formation of black mold growth.

 

Condensation problems can be improved by:

• Reducing moisture or preventing it from spreading throughout the house. Use lids on pots while cooking, avoid drying clothes indoors or too close to a source of heat, and wipe the water droplets away as soon as they form.
• Improving ventilation. Install a fan or a dehumidifier in rooms with a high level of moisture such as bathrooms and kitchens, leave trickle vents open to remove water vapors, and do not place furniture directly against internal walls, as this will prevent the air from circulating.

Rising Damp

The presence of rising damp is not as easily detected as condensation, mainly because it occurs below ground level, but as it gets worse, it will start to move up through walls. Most walls allow a certain quantity of water inside, but it’s usually prevented from rising above the safety level by a horizontal plastic or slate strip inside the wall called damp-proof course.

Symptoms of rising damp include patches above skirting boards and floorboards, peeling paint and wallpaper, and stained or crumbling plaster. You may also notice damp smells and a tide mark along walls and ceilings.

In repelling moisture from beneath, you must first confirm that the damp-proof coursing is working effectively, for which you need to get help from an experienced builder or damp specialist. If no damp-proof course exists, many homeowners opt for a chemical damp-proof solution that is injected inside holes drilled into the mortar course. Since this treatment involves the structure of a building, it’s recommended to be carried out by a reputable company that can provide guarantee for its services.

Penetrating Damp

Penetrating damp is caused by water leaking circulating through walls, but the movement of water is horizontal rather than vertical (as is the case with rising damp). It can come from a variety of sources, most often overflowing gutters, leaking downpipes, broken or missing roof tiles, poorly fitting doors and windows, faulty wall flashing, or damaged pebbledash.

Penetrating damp problems may also occur if the ground level outside covers the damp-proof coursing designed to allow air circulation beneath suspended floors. This type of damp usually shows up through blotchy patches on walls, damp and crumbling plaster, the presence of mildew, and water on the surface.

In order to treat penetrating damp, you must first identify the source of moisture, and then request the services of an expert to repair the fault. Depending on the extent of the damage, you may need to install new guttering or repointing your roof.

The best way to prevent penetrating damp is to keep the house in good repair. Uncover vents that are blocked by soil or vegetation, inspect wall and roof flashings and claddings for leaks, replace any missing roof tiles, and ensure exterior coatings are properly applied.

Water leaking into your property is never something to ignore. Moisture in homes is constantly associated with a variety of health problems, ranging from eye and throat irritation to allergies and asthma. Damp environments are prime breeding grounds for bacteria and an ideal environment for pests such as termites, ants, rats, cockroaches, and other moisture-loving critters. Your local pest control company will be able to help you determine whether damp is inviting pests inside and prevent the serious health and comfort issues associated with a moist environment.

 

About the Author

Daniel Mackie, co-owner of Greenleaf Pest Control, is a Toronto pest control expert well-known as an industry go-to guy, an innovator of safe, effective pest control solutions, and is a regular guest on HGTV. Mackie, along with business partner Sandy Costa, were the first pest control professionals in Canada to use detection dogs and thermal remediation for the successful eradication of bed bugs. In his free time, he is an avid garde