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Insulating and Venting When There is No Roof Soffit

May 21, 2016

In most residential homes, the soffit (and associated vents) is the structural part of the roof that "hangs over" the side of the home. The principle behind soffits is to allow air to circulate in and around the attic. However, not all homes (especially older homes) have overhangs, and therefore they have no soffits. It could be said that this makes for an easier insulation project in the attic, because there's no worry about inadvertently covering over soffit vents with insulation material. However, these scenarios require another solution to address ventilation. For homes without soffits (or narrow ones), the attic can still be very effectively insulated. This is accomplished by installing insulation to include all of the corners, angles and wedges where the attic slope meets the attic floor. Clearly, the required amount of R-Value must be determined to ensure that appropriate thermal insulation is installed. In terms of product, batt insulation will be different than blown insulation, which will be different than spray polyurethane foam insulation. Aside from the technical aspects of insulating and venting an attic without a soffit, this is a project that requires both experience and expertise. To begin with, the attic must be sealed to make the space airtight, and to ensure that there is no air leakage. For professional installation contractors, sealing is key in assuring peak performance for the insulation that will be installed. And since fiberglass/cellulose insulation itself does not prevent air movement, no installation is complete without the sealing effects of spray foam. For many reasons, a DIY approach to this type of attic insulation isn't recommended. The benefit of an expert install is threefold: the attic is professionally assessed to determine needs; product is selected based on those specific needs; and installation is expedited to assure optimum long-term performance. When it comes to product selection, an expert installer can also be an advantage in selecting the product (or combination of products) that will best suit the project needs. Beyond the insulation, attic air sealing is absolutely critical to the "system". Without adequate air sealing, there is a tendency for conditioned air from the house to escape into the attic space - and that will impact the home's energy efficiency, as well as energy consumption. This is a perfect scenario for wasting heat during the winter and air conditioning during the summer. At the same time, as the HVAC system works to compensate for the energy wastage, seasonal utility bills begin to grow out of control. Properly ventilating an attic, when there is no built-in soffit, can be a challenge. But for experts, a well-designed system will ventilate effectively, while complementing the installed insulation - it all has to work in tandem. Short of suggesting structural changes, or a new soffit, a reputable insulation contractor will make sure to create a "system" that will be well sealed, well ventilated, and well insulated. They key is to do it right the first time, without taking any shortcuts. In southern Ontario, and throughout the province, Great Northern Insulation installs efficient attic systems that incorporate both insulation and ventilation. All products and installations are fully warrantied, and customer satisfaction is assured on every project.

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

TOLL FREE: 1-800-265-1914

Central Ontario

29 Ferndale Industrial Drive
Barrie, Ontario
Canada L4N 9V5

TOLL FREE: 1-800-265-1914

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


Great Northern Insulation - Better Business Bureau Profile.

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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