How Much Insulation Do You Actually Need?
If you've ever stood in a basement with a tape measure trying to guess how many bundles to buy, you're not alone. Order too little and you're back for a second trip mid-project. Order too much and you've paid for material sitting unused in your garage. Getting the number right isn't complicated once you know the two things that actually matter: your square footage, and your coverage per bundle.
Start with your square footage
Measure the area you're insulating — walls, basement, or floor — in square feet. For a wall, that's height times length for each section you're covering (don't forget to subtract large openings like garage doors, but don't bother subtracting small things like electrical outlets or single windows; the waste factor covers that).
If you're insulating multiple rooms or a full basement, add up each section separately before moving to the next step. It's easier to catch a measuring mistake in one room than to untangle a combined total later.
Know your coverage per bundle
Every insulation product covers a different amount of area per bundle, depending on its thickness and how many pieces come packed together. A bundle of 2" XPS board doesn't cover the same square footage as a roll of R20 fiberglass — so this number changes depending on what you're buying, not just how much space you have.
This is the step most people either skip or estimate badly, which is exactly where over- and under-ordering come from.
Don't forget waste
Even careful installers lose some material to cuts, corners, and odd angles. A common rule of thumb is to add about 10% to your total before calculating bundles — it's cheap insurance against a last-minute supply run.
Do the math without doing the math
Instead of working all this out by hand, we built a calculator that does it for you: pick your product, enter your square footage, and it tells you exactly how many bundles you need and what the total comes out to — tax included, in Canadian dollars.
Try the Insulation Calculator →
Not sure what product or R-value you need first?
If you're not sure what R-value your project needs to hit, Ontario's Building Code sets minimums for walls, basements, floors, and attics — and they're all different. We built a quick reference tool for that too, so you're not guessing before you even get to the calculator.
Check Your R-Value Requirement →
Buying in bulk?
Orders over $1,000 (pre-tax) automatically get a 5% discount — no need to ask, it's applied when you check out or when we quote you. All our pricing is tax-included, so the number you see is the number you pay.
Pickup or delivery
Once you know what you need, pickup is available 10 AM–3 PM, Monday to Saturday (closed Sunday), or by appointment, at 503 Sherrer Wy in Winchester. We also deliver across Ontario — reach out for a quote if you'd rather have it brought to your site.
Have a project that doesn't fit neatly into one calculation — multiple rooms, mixed insulation types, or an unusual layout? Contact us and we'll help you work out exactly what you need.
