Call Now1.800.265.1914


Why is There Mold on My Walls?

It’s easy to notice mold on walls, window frames, and in corners around the house. And while not all molds are visible, the telltale signs are obvious to most homeowners. Once noticed, however, it’s important to determine the source and extent. But it’s equally important to find the cause that is underlying – without that, mold will continue to flourish even after being cleaned and removed.

Essentially, mold requires moisture to propagate. Mold cannot sustain in a dry, well-ventilated space. So when moisture is allowed to accumulate, mold will thrive. Typically, it’s the home that’s poorly ventilated that contributes to moisture accumulation and mold growth. And inside most homes, there is no lack of moisture – everything from showers, to cooking, to indoor houseplants.

In terms of science, warm indoor air rises. And since warm air is full of moisture, accumulation generally concentrates on walls, ceilings, and corners. It doesn’t always signal big problems, but if mold is noticed, it means that both cleanup and prevention are required. One way or another, proper flow-through ventilation throughout the house will have to be addressed and initiated.

For the experts at Great Northern Insulation, properly ventilating the house is just as important as properly insulating. In fact, it’s integral for the “building envelope” to function. Signs of mold are just one symptom of inadequate air circulation and ventilation. As for solutions, the benefits of a well ventilated home are wide reaching:

  • much improved indoor air environment and air quality
  • consistent and balanced heating/air conditioning cycles
  • much reduced indoor moisture levels around the home
  • enhanced seasonal comfort during winter and summer

In most cases, poor ventilation (especially when the attic is inadequately vented) is a prescription for moisture to collect, and mold to develop. Conversely, a well ventilated home will not suffer.

Most Popular Questions

FREE Online Energy Audit

Conduct a FREE Online Energy Audit of Your Home with the MIT Award Winning My Energy Expert Application.

Western Ontario

935 Keyes Drive
Woodstock, Ontario
Canada N4V 1C3

Phone: 1-800-265-1914

Fax: (519) 539-7946
TOLL FREE: 1-800-265-1914

Southwestern Ontario

7035 Industrial Drive
Comber, Ontario
Canada N0P 1J0

TOLL FREE: 1-800-265-1914

Muskoka, Haliburton, Northern Ontario

1027 Jones Road
Gravenhurst, Ontario
Canada P1P 1R1

TOLL FREE: 1-800-265-1914

Central Ontario

29 Ferndale Industrial Drive
Barrie, Ontario
Canada L4N 9V5

TOLL FREE: 1-800-265-1914

Eastern Ontario

103 North Port Road
Port Perry, Ontario
Canada L9L 1B2

TOLL FREE: 1-800-265-1914

GTA & South Central Ontario

450 Industrial Dr,
Toronto (Milton), Ontario
Canada L9T 5A6

TOLL FREE: 1-800-265-1914


Great Northern Insulation - Better Business Bureau Profile.


GNI is the Authorized & Trusted Insulation and Air Sealing Installer for Lowe’s

Enenrgy Savers

Energy Saving

Energy saving and energy efficiency is easier than one might think. Great Northern Insulation helps to identify performance issues, while taking advantage of improvement opportunities.

100% Canadian

100% Canadian

Great Northern Insulation is recognized as Canada's largest full-service insulation contractor. GNI is 100% Canadian owned, proudly serving Ontario customers since 1980.

Foam Masters

Do it right the first time
- with foam mastersTM

WALLTITE® ECO™ is a high-performance system, professionally installed by certified and approved specialists. Its C.C.M.C. approved (Canadian Construction Materials Centre) - with product quality guaranteed - and with installation by highly trained experts with the technical know-how to do the job right, the first time.


Best of 2017

From reputation to responsiveness, HomeStars consistently ranks Great Northern Insulation at better than 95% for customer satisfaction. Thanks to everyone for the great ratings! 


Gold Certification promise

GREENGUARD® Gold Certification ensures the strictest criteria for low-level chemical emissions. Certified products are safe for individuals with sensitivities (children/elderly) and safe for use in school environments and health-care facilities. The product certification is widely recognized by the LEED Rating System (Leadership in Energy/Environmental Design).


Multi-attribute product certification

ECOLOGOTM is an accredited sign of environmental performance – holistic – green – sustainable - and compliant with strict, third party standards. Life cycle criteria for product certification may include manufacturing and operations; health and environment; product materials and performance; and product innovation, development, and management.


3MTM products.
Quality + Performance = Savings

3MTM energy-saving products are designed to keep warm air in, and cold air out, while keeping energy bills down. Products optimize energy efficiency in buildings and homes; improve indoor environment for occupants; and effect the reduction of seasonal energy costs. 3M products are authorized for LEED credits (Leadership in Energy/Environmental Design).


Baeumler ApprovedTM
Professional, Certified and Insured

Baeumler ApprovedTM gives you peace of mind when connecting with contractors, trades and home service providers. All Baeumler Approved members have demonstrated high quality work for customers and other trade professionals. Members must also have Workers Compensation, liability insurance of at least $1,000,000 and prove professional certification.

Holmes and Holmes

Holmes and Holmes


Mike Holmes and his son Mike Jr. (MJ) convert MJ’s bachelor bungalow into a two-storey home for MJ and his girlfriend Lisa. Choosing the newest materials and build techniques, the father and son team follow Mike’s famous motto – “Make it right.” The show can be watched on HGTV and DIY Network.


Enbridge Incentives

The Energy Conservation Program provides incentives of up to $1,600 to customers who achieve energy efficiency and fuel savings – and Great Northern Insulation can pave the way.

Please, enter a valid value

Incorrect values!