Attic Insulation Products

House Cross section Solid State Home Inspection

Heating and cooling our homes is a constant battle with weather and nature. In the winter, we are adding heat inside of our homes to stay warm and in the summer, we are air conditioning, ventilating, or shading our homes to keep the cool in.


Much of the heat exchange in our homes happens in our attic space. In the summer, a properly ventilated attic can be 10c hotter than the weather outside our home and in the winter, the attic can be as cold as the air outside. A deep layer of insulation in the attic can make a big difference keeping us warm in the winter and cooler in the summer.


Insulation “R” Values

All material on the planet is able to resist heat movement to some degree. In our attics, we are looking for materials that will stay in place well, are fire resistant, are economical to install, and offer high resistance to heat transfer. The resistance of insulation to transferring heat is expressed as an “R” value with the “R” value often expressed as the "R" per inch. Multiplying the depth of the insulation material against the “R” value per inch yields the total estimated insulation in an attic.


Target R values for construction have been increasing in the last few decades. In the early 70’s, an R-12 was considered adequate insulation. In the 80‘s and 90‘s, municipalities started to require R-20, R-30, then R-40 insulation in new home construction. Today, the Government of Canada encourages R-50 insulation through national energy rebates and R-50 is required in many municipalities in new home construction.


Common Types of Insulation

Fiberglass Batts

Fiberglass Batts -

Fiberglass batts are very common in construction where they are installed between wall studs or roof rafters. Fiberglass batts have an R-value around 3.3/inch. A common 4” thick fiberglass batt has about an R12 value. There are high end some high end products which are up to 8.5” thick with an R30 value.


Loose Fill Fiberglass Solid State

Loose-Fill Fiberglass -

Also called Blown-in’ fiberglass, this loose fill product has advantages in the attic over batt insulation. It is easier and faster to install in tight spaces and a thicker blanket can be installed more evenly. Loose fill fiberglass has an R-value of about 2.2 per inch. An R-50 installation will have nearly 2 feet of quite light insulation material. With this depth of material, it is important for attic ventilation that installers insert baffles in the attic to allow air to rise from the soffits past the insulation layer.


Loose Fill Cellulose

Cellulose -

Cellulose insulation is primarily recycled newsprint or other organic recycled material that has been treated to become fire resistant. It is blown in as a loose fill similar to the fiberglass product above and has the same install advantages and challanges. Cellulose insulation has a slightly higher R-value than fiberglass at R 3.6 per inch. An R-50 installation will have 14” of material in the attic.


Spray Foam

Urethane Foam -

Foam installations require a higher skill level to install and much more manpower. Foam is applied by spraying the attic’s insulated surface with a liquid that expands on contact. Urethane foam offers a very high R value of 5.3/inch meaning an R-50 installation is under 10” deep.



Vermiculite and Asbestos

Vermiculite is a natural mineral that pop’s like popcorn when heated to create a fire-resistant insulation product. Vermiculite has been used for over 100 years as a common insulation although it’s use diminished by the 60‘s in favour of newer and higher R-value fiberglass materials. Vermiculite insulation has an R value around 2 per inch. An R-50 installation in theory would take over 25” of material.


Unfortunately one of the major mines for vermiculite in North America also contained asbestos. Due to the dangers of asbestos (see our asbestos article here), vermiculite insulation always needs to be tested for asbestos before being disturbed or removed. If we identify vermiculite insulation in a home inspection, we will never walk on it or disturb it as a safety precaution. 


Urea-Formaldehyde Foam Insulation

Urea-formaldehyde foam insulation (UFFI) was installed for a short period in the 1970’s to 1980 as very quickly after being used in homes there was a health controversy which suggested toxic levels of formaldehyde were being off gassed into peoples homes. It took nearly a decade for scientific testing and class action lawsuits to resolve the issue but today, the Government of Canada says UFFI insulation is completely safe. Unfortunately for UFFI, the market had moved away from spray foam during the controversy and new spray foam products were developed based on Urethane foam. If we see UFFI in a home inspection, we simply identify it as a foam insulation without additional comment.


Uneven and Missing Insulation

In order for any insulation to be effective, it needs to be evenly spread and cover the entire ceiling area. We find in home inspections poor original installation, movement of people, and even nesting critters can create uneven insulation levels in the attic which will impair the benefits of the insulation and should be corrected.


We also often find in home inspections areas completely missing insulation either from original installation or from insulation falling or sliding off of sloped surfaces. These areas need maintenance to ensure the entire insulated surface is correctly insulated.


Final Thoughts

No matter the insulation you have in your attic, the effectiveness of insulation is based on the depth of the material, not the material itself. Ask your home inspector or insulation contractor to give you an estimate of the R-Value for your attic insulation. 


If you would like lower heating bills in winter and a cooler home in summer, consider upgrading your insulation levels to R-50. One of the great things about insulation is you can usually mix and match products. So just because you have 4” fiberglass batts does not mean you can’t add 15” of blown in cellulose or fiberglass to help improve your comfort.


By James Bell - Owner/Operator of Solid State Inspections Inc.