Quick answer: This walkthrough follows a typical GTA bungalow attic from about R-12 to R-60: assessment, air sealing, baffles, blown-in cellulose and rebate paperwork. On a $3,000 after-tax job, the Ontario attic rebate pays the full $1,250, bringing the net cost to $1,750. example — not a specific customer. It shows the steps and math we use on real jobs.
Updated November 2026
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Key takeaways
- Air sealing the attic floor comes before new insulation.
- Baffles keep insulation from blocking roof vents.
- The rebate is fixed once your job cost passes twice the cap.
The home
| Detail | Value |
|---|---|
| Home type | 1960s bungalow, Scarborough |
| Attic area | About 1,100 sq ft, open attic, truss roof |
| Heating | Enbridge natural gas |
| Existing insulation | About 4 inches of old fiberglass batts, roughly R-12 |
| Complaints | Cold bedrooms, icicles at the eaves every winter |
What the assessment found
- Thin, uneven insulation. About 4 inches, with gaps around the hatch and bathroom fan.
- Air leaks. Open gaps around plumbing stacks, ceiling light boxes and the top of interior walls.
- Bathroom fan venting into the attic. Moist air was going straight into the attic.
- Blocked soffit vents. Old batts were pushed into the eaves.
- No vermiculite, no animal damage. So no removal was needed.
The plan
| Item | Why |
|---|---|
| Seal top plates, stacks, wiring holes and light boxes | Stop warm, moist air reaching the attic |
| Duct the bathroom fan to an exterior roof or soffit vent | Remove moisture source |
| Install baffles at every rafter bay on the eaves | Keep vents open |
| Insulate and weatherstrip the hatch | The hatch is often the biggest single leak |
| Blow cellulose over existing batts to R-60 | Meet rebate target with a buffer, match new-home code level |
| Install depth markers | Proof of depth for the homeowner and the rebate |
Why cellulose here
| Option | Fit for this attic |
|---|---|
| Blown cellulose | Good: open attic, fills gaps around framing, about R-3.5 per inch |
| Blown fiberglass | Good: also works, needs more depth for the same R-value |
| Spray foam | Not needed for an open, vented attic; much higher cost |
R-60 minus the existing R-12 leaves about R-48 to add. At about R-3.5 per inch, that is roughly 14 inches of cellulose.
The day of the job
- Arrival and protection. Floors and the hallway under the hatch are covered.
- Air sealing. Leaks are sealed from the attic side.
- Fan duct. The bathroom fan is ducted outside.
- Baffles. Installed at each bay along the eaves.
- Blowing. Cellulose is blown to depth, checked against the markers.
- Hatch. Insulated and weatherstripped.
- Clean-up and photos. “After” photos and readings are taken for the rebate.
Typical duration for a job like this: one day.
The cost math
| Line | Amount |
|---|---|
| After-tax price (example) | $3,000 |
| Rebate tier | R-12 or less → R-50, max $1,250 |
| 50% of after-tax price | $1,500 |
| Rebate paid (lesser of the two) | $1,250 |
| Net cost | $1,750 |
The result (simplified)
Going from R-12 to R-60 cuts heat flow through the attic insulation layer by about 80% (1 − 12/60). With the air leaks sealed and the fan ducted outside, the conditions that cause ice dams and attic moisture are also reduced.
Checklist you can reuse
- Measure existing depth and check for vermiculite
- Find and seal air leaks first
- Check every bathroom and kitchen fan vents outdoors
- Keep soffit vents clear with baffles
- Insulate and weatherstrip the hatch
- Reach at least R-50 (aim for R-60)
- Get before/after photos, depth readings and markers
Template: write up your own project
Use this outline to document your job, or ask your contractor for it:
- Home type, age, attic area, heating type
- Existing insulation (type, depth, estimated R-value)
- Problems found (air leaks, ventilation, moisture, animals, vermiculite)
- Scope of work, line by line
- Target R-value and depth
- After-tax price, rebate tier, rebate amount, net cost
- Photos and depth readings, before and after
Frequently asked questions
Is this a real customer project?
No. It is an example built on how we approach real jobs and on the published rebate rules. Your home, scope and price may be different.
Why not just add insulation and skip air sealing?
Insulation slows heat moving through it, but it does not stop air. Warm, moist air leaking into the attic causes heat loss, ice dams and mould. Sealing first makes the new insulation work better.
Do I need to remove the old batts?
Not if they are dry, clean and not contaminated. New insulation can go right on top.
How long does a bungalow attic take?
A typical bungalow top-up with air sealing and baffles takes about a day. Removal, mould or animal clean-up adds time.
Get your own walkthrough
We will assess your attic and give you a written plan like this one, with your rebate shown. Call (647) 250-0606 or book online. Learn more about attic insulation and rebates.