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Installing Fiberglass Insulation in the Attic and Roof

January 29, 2016

Whatever insulation product is being installed in the attic, the objective should be the same: to eliminate "heat transfer" in the space that is being insulated. Essentially, this means stopping air leakage - stopping warm indoor air from leaking out in winter, and stopping warm outdoor air from coming in during summer. Without good insulation in the attic and roof, a home will suffer from energy inefficiency - energy consumption will be out of balance, and utility bills will be high.For insulation professionals, the attic space represents one of the most important portions of the home's "building envelope". Because of it's location at the top of the home, and the expansive space, the attic always has a dramatic effect on "heat transfer". As such, good insulation, professionally installed, can positively effect heating dynamics in winter and cooling dynamics in summer. Its therefore vital to choose an attic insulation product that will perform. With attic insulation, professional installers have very specific aims: to stop undesirable air movement throughout the space; to prevent moisture from collecting in and around the space; and to enhance R-Value where new insulation is being installed. Here, fibreglass insulation can do an adequate job in terms of product performance, although many experts recommend combining an additional insulation product for a finished space that is more comprehensive. The two most popular fiberglass insulation products on the market are batt insulation and loose fill insulation. With advantages and disadvantages, a professional contractor can assess the products for a homeowner, and can then provide a viable plan. In terms of positives, fiberglass is asbestos-free; non-corrosive; odor free; and non-combustible. A good install will not settle measurably over time, and with good ventilation created, the fiberglass will not hold moisture (in small amounts), Neither of the fiberglass insulation products will attract animals, insects, or rodents. And with proper ventilation created, fiberglass should not be deteriorating. Best of all, fiberglass attic insulation is a cost effective project offering years of performance. There is one particular disadvantage with fiberglass insulation that causes concern for the professionals - fiberglass does not seal a space effectively. And because sealing is critical to an attic, the install must be enhanced with another product. For the professionals, the best insulation for the attic is Spray Polyurethane Foam. SPF delivers far better performance than any comparable product, and with more benefits. Its considered a premium product, and may therefore not suit every budget. But for the experts, nothing comes close to an SPF application. One of the better options for the attic is the so-called "hybrid" install. Here, a contractor will combine Spray Polyurethane Foam with one of the fibreglass products in one installation. Performance benefits are derived from each product; the overall results are impressive; and the project is very cost-effective. In a "hybrid" installation, the SPF application provides sealing and insulation far beyond any other product. As for the fibreglass application, the added R-Value enhances energy efficiency, while the dollar-value ensures cost-effectiveness. The "hybrid" install brings both great results and great value. Whatever the product chosen, attic insulation requires a professional touch to deliver maximum performance. And like any home improvement project, experts usually ensure the benefits and results that a homeowner expects.

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

Muskoka, Haliburton, Northern Ontario

1027 Elwell Park Road
Gravenhurst, Ontario
Canada P1P 1R1

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Central Ontario

29 Ferndale Industrial Drive
Barrie, Ontario
Canada L4N 9V5

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Greater Toronto Area

2 Guided Court
Etobicoke, ON
M9V 4K6

TOLL FREE: 1-800-265-1914

GTA East

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

TOLL FREE: 1-800-265-1914

South Central Ontario

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

TOLL FREE: 1-800-265-1914

Eastern Ontario

1035 Moodie Dr #1,
Nepean, ON
K2R 1H4

TOLL FREE: 1-800-265-1914

Niagara Region

25 Lincoln Ave
St. Catharines, ON
L2P 2C7

TOLL FREE: 1-800-265-1914


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Homestars Best of 2021 Award

Best of 2021

HomeStars has ranked Great Northern Insulation as a company that goes above and beyond in every aspect of business for the year of 2021.

Homestars Best of 2022 Award

Best of 2022

HomeStars has ranked Great Northern Insulation as a company that goes above and beyond in every aspect of business for the year of 2022.


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

Trusted for Over 40 Years

Over 40 Years in Business

At GNI, we service your project with the most experienced staff in the industry. Ongoing professional development is an obsession at GNI and we will not compromise at any level to bring to our customers the very best Installers, Sales Representatives, Customer Care Personnel, Field Superintendents, Estimating and Technical Support to your project.

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

January, 2021 regulatory phaseout of hydrofluorocarbons (HFCs) with the introduction of WALLTITE CM01. Using hydrofluorolefins (HFOs) with lower global warming potential (GWP) compared to HFCs, WALLTITE CM01 is the next generation of spray foam insulation.



Heatlok® Soya HFOTM leverages Honeywell’s latest Solstice® Liquid Blowing Agent technology. This new hydrofluoroolefin (HFO) blowing agent is the most environmentally conscious blowing agent produced to date, with a zero ozone depletion potential (ODP) and a global warming potential (GWP) of 1, which is more than two orders of magnitude (99.9%) lower than HFCs used in this industry.


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).

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.


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The Home Efficiency Rebate Plus program offers up to $10,000 in home reno rebates – and Great Northern Insulation can pave the way.


Great Northern Insulation proudly abides by a renovation-specific Code of Conduct set by RenoMark™.


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As Seen on Love It or List It

The GNI crew have been featured installing insulation on Love It or List It - have you seen our logo in an episode?

Climatizer Cellulose


CLIMATIZER PLUS cellulose insulation is manufactured from a minimum of 85% locally-sourced post-consumer recycled newsprint. Non-toxic additives are applied to the uniquely fiberized paper generating a building material with superior thermal and acoustic properties, as well as exceptional resistance to fire, moisture, mould and pests.

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