What Causes Mold Around the House

Knowing what causes mold to grow indoors can help you spot mold problem well before it gets out of hand, as well as effectively prevent mold contamination from happening in the first place.

Mold spreads around by releasing microscopic airborne spores which at some point can end up inside of your house. Once the spore lands on wet surface and certain conditions are met, it will start growing.

Mold needs these to grow

Mold Spores

Invisible to the naked eye, mold spores usually get inside your house from outdoor.

Moisture

Prolonged exposure to wet conditions is required in order for mold to start growing.

A food source

The abundance of organic materials makes indoors a perfect breeding ground for mold.

Oxygen

A steady supply of oxygen plays a vital part in mold growth and reproduction cycle.

Lack of Sunlight

Direct exposure to sunlight is deadly to mold, that’s why it prefers to grow in the dark.

Optimal Temperature

Temperature levels of residential houses create optimal conditions for mold to grow.

So what exactly causes mold in a house?

In every major area of the house, there are plenty of possibilities for mold spores to flourish. Anything, from a plumbing problem to a lack of proper ventilation could lead to creating optimal conditions for mold to start growing indoors.

To learn more about what causes mold to grow in particular areas of your house, check out our detailed illustrations below.

Causes of Mold in Attic

Minor and Major Roof Leaks
Faulty or Missing Insulation
Ice and Snow Damming Problems
Improperly exhausted Dryer, Bathroom and Kitchen vents

Heaters and Furnaces in the attic
Condensation Effect during the cold season
Improper Ventilation or lack of it

Causes of Mold in Basement

Leaking plumbing pipes
Flooding (nature or plumbing caused)
Broken, clogged or sagged gutters or downspouts
Clogged/Faulty footer drains
Sump Pump failures
Sloping grounds/ groundwaters

Cracks in Foundation and Foundation Walls
Rain and Melting Snow from windows
Water Condensation on cold surfaces
Lots of materials mold loves to grow on
Dust and dirt accumulated with time
Poor Air Ventilation / Circulation

Click here to learn more about how you can remove mold from your basement.

Causes of Mold in Crawl Space

Bare earth floor with porous soil near foundation
Missing or damaged Vapor Barrier
Ground water due to high water tables
Rain and Flood water
Cracks in Foundation and Foundation Walls
Plumbing related problems

Faulty or missing Air Duct Insulation Materials
Poor Ventilation or Lack of it
Outdoor air getting into crawl space from outside
Water Evaporation leading to condensation
Exposed Plumbing Pipes and Joists

Click here to learn more about how you can remove mold from your crawl space.

Causes of Mold in Bathroom

Plumbing Problems (Leaks & Overflows)
Water Condensation on walls & ceiling
Water Evaporation
Frequently running watter
Wet surfaces after showering

Wet surfaces from Hot Steam
Water Puddles on the floor and around sink
Broken toilet and bathtub seals
Poor Ventilation / Air Circulation
Failed grout and/or caulking between tiles

Read more on our guide on how to remove mold from the bathroom.

Causes of Mold in Kitchen

Water Leaks from Sink and Dishwasher
Plumbing Problems (Leaks & Overflows)
Water spills / Running tap water
Condensation on plumbing pipes

Steam from boiling water / cooking
Steam from Dishwasher
Plenty of food molds loves to grow on
Poor Ventilation / Air Circulation

Read more on our guide on how to remove mold from the kitchen.

Causes of Mold in Air Ducts

Causes of mold inside an air duct or HVAC.

Dust, dirt, debris and pet hair collected in the vent
Clogged air duct filters
Using basic fiberglass filters in houses with pets and other sources of micro-particles
Leaks around duct joints
Wetted fiberglass-lined ductwork surfaces
Damaged or missing air duct insulation

Damaged or missing foil vapor barrier
Condensation on metal parts of HVAC units
Improper use or absence of Drain Pans
Improper mixing of outside and inside air
Saturated air coming from air conditioner evaporator
Weak (slow) air flow coming out of the grill

Read more on our guide on how to remove mold from the air ducts.

Causes of Mold on Outside the House

Causes of mold on the exterior of a building.

The nearly constant presence of moisture
Rainwater running down the wall surface
Downspouts emptying next to the wall
Siding made of porous materials such as wood, stucco, etc
Vines and shrubs growing along the side of your house
Broken, clogged or sagged gutters or downspouts

Leaks and condensation from air conditioner drain lines
Incorrectly placed sprinklers system
Water wicking into the foundation from the sloping ground
Poor ventilation in tight areas along the walls
Abundance of organic materials mold loves to grow on

Need our services? At Above & Beyond, we offer a range of services including mold inspection and mold remediation to our customers in New Jersey and New York. Call now for free consultation @ (732) 490-5900.

For an infographic version of this page please visit this page.

PROVIDING MOLD SERVICES IN EVERY COUNTY IN NEW JERSEY:

Somerset County, Cumberland County, Union County, Ocean County, Hudson County, Camden County, Gloucester County, Passaic County, Essex County, Mercer County, Atlantic County, Middlesex County, Bergen County, Salem County, Cape May County, Monmouth County, Sussex County, Morris County, Burlington County, Hunterdon County, Warren County.

PROVIDING MOLD SERVICES IN THESE NEW YORK COUNTIES:

Nassau County, Orange County, Suffolk County, Westchester County