Fiberglass, cellulose, spray foam and mineral wool can all be used in attics. The right choice depends on what your attic needs and the condition of the insulation already there.
For many Toronto and GTA homes, the first question is whether the attic simply needs more insulation or whether moisture, air leaks or damaged insulation need to be fixed first.
Which Attic Insulation Material Should You Choose?
| If your attic… | Start by considering… | Why |
|---|---|---|
| Simply needs more insulation on the attic floor | Blown-in fiberglass or cellulose | Both are practical for common attic top-ups |
| Has open, regular framing | Fiberglass or mineral wool batts | Batts fit well between accessible framing |
| Has an irregular floor or many obstructions | Blown-in fiberglass or cellulose | Loose-fill covers around framing, wiring and other obstacles |
| Needs insulation and air sealing together | Spray foam | It can address both as part of the same attic or roof assembly |
| Has wet, damaged or contaminated insulation | Correct the problem first | New insulation will not fix the underlying issue |
Not sure which situation matches your attic? Mas Air offers free attic assessments across Toronto and the GTA to check the existing insulation, air leakage and ventilation before recommending a material. Book an attic assessment online.
Fiberglass vs. Cellulose
For a typical vented attic that only needs more insulation on the attic floor, blown-in fiberglass and cellulose are usually the main options.
Blown-in fiberglass works well for large attic areas and common top-ups.
Cellulose is also well suited to retrofit attics and can fill around framing and other obstructions.
Neither material stops air leaks. Gaps around wiring, plumbing and ceiling fixtures should be sealed where needed before more insulation is added.
When Does Spray Foam Make Sense?
Spray foam is more useful when insulation and air control need to be handled together.
It may suit roof decks, cathedral ceilings or other attic designs that need a different approach from a standard vented attic.
If the attic only needs more insulation on the floor, blown-in insulation is usually the simpler option.
Where Does Mineral Wool Fit?
Mineral wool is commonly installed as batts.
It can work well where framing is open and accessible, especially when fire or sound performance also matters.
For a basic attic-floor top-up, blown-in fiberglass or cellulose is usually easier to install.
What Should You Check Before Choosing Attic Insulation Material?
Before adding new insulation, check the condition of what is already in the attic.
Existing insulation may stay in place if it is dry, clean and still usable. Mas Air may recommend a top-up when the insulation is simply too thin or uneven.
If the existing material is wet, contaminated or badly damaged, old attic insulation removal may be needed before new insulation is installed.
Air leaks and blocked attic ventilation should also be corrected before adding more insulation.
These conditions can change which material makes sense and whether a simple top-up is enough.
Get the Right Attic Insulation Material for Your Home
Choosing the material is only part of the job. An attic assessment can show whether your home needs a simple top-up, air sealing, insulation removal or a different approach.
Mas Air Home Comfort provides free attic and roof insulation assessments for homeowners across Toronto and the GTA. If your existing insulation is still usable and only needs a top-up, Mas Air will not recommend a full replacement.
Book your free attic insulation assessment online or call 647-360-6623 for installation inquiries.
⭐ Why homeowners choose Mas Air:
- Free attic and roof insulation assessment
- CSA-certified insulation materials
- Transparent recommendations based on the condition of your attic
- 100+ five-star customer reviews
- Service across Toronto and the GTA
