What causes mould/mold to grow in buildings?

Building science failure is what causes mold in homes or buildings. Period. Building science failure is dampness, water leaks, high humidity, condensation, and poor ventilation. When elevated moisture and any type of organic material meet (e.g. damp cement floor and cardboard boxes), the potential for mold develops. It is this marriage between natural materials and dampness that begins the mold growth cycle to start in our homes or buildings.

I don’t see water in my basement, how can I have mold?

Typically, building occupants smell something before they see any signs of visible staining. When mold begins to grow, it requires food and moisture. The food can be anything mother nature produces – paper, dust, wood, skin cells (organics). The moisture can be caused by high relative humidity, dampness, water leaks, condensation, or osmosis.

What does mold smell like?

Frequently, occupants complain of musty, earthy, damp smells when descending the stairs into the basement.

What causes moisture in my basement?
  • Building science or building “skin” failure
  • Active water leaks from roof, window, doors, or flashing
  • Condensation inside wall cavities or around the wall and light switch outlets
  • Under basement floor vapor pressure and wall cracks
  • Poor site grading – water draining back toward the home
  • Over humidification
  • Poor ventilation
  • Storm water management – lack of eaves-trough
How do you stop mould/mold-related issues from returning to the indoor environment?

By simply identifying what combination of building failures is causing the problem, and providing tried and true remedies that solve the problem.

Who can you call to identify these building science conditions?

Indoor Air Quality Ottawa with over 6,000 inspections and 20+ years of building science experience.