Roof cost per square foot in Quebec: what the number hides

Why everyone looks for a per-square-foot price

It is the first thing people type into Google before calling a roofer, and I understand exactly why. You want a benchmark. A simple number to multiply by the size of your roof so you know whether you are talking about $8,000 or $20,000 before anyone shows up at your door.

The problem is that price per square foot is the easiest measure in our trade to take out of context. Two houses of the same size, on the same street, can be $4,000 apart. Not because one contractor is dishonest — because the two roofs are not the same job.

Let me explain how it is actually calculated, what moves the number, and above all how to tell a serious quote from an estimate tossed out over the phone.

The "square": the unit we actually use

One thing worth knowing before you compare quotes: in Quebec construction, we do not talk in square feet when we talk about roofing. We talk in "squares". One square is 100 square feet of roof surface.

So when a roofer tells you "your roof is 18 squares", they mean 1,800 square feet of surface to cover. It is also how materials are sold: a bundle of shingles covers a fraction of a square, and manufacturers calculate their warranties on that basis.

An important nuance: the roof's surface is not the footprint of your house. A pitched roof covers more area than the house beneath it, and the steeper the pitch, the bigger the gap. That is the first reason a figure found online so often misses.

What actually moves the price

At equal surface area, here is what explains almost the whole gap between two quotes:

• •The slope: a steep roof needs safety equipment, slows the installation and increases the real surface area
• •How many layers come off: one layer or three layers of old shingles is not the same time or the same volume of debris
• •Complexity: dormers, valleys, hips and chimneys multiply the cuts, the flashing and the hours
• •Access: a narrow lane or a shared roof completely changes the logistics of the job
• •The condition of the deck: the plywood underneath, which you only see once the old roof is off
• •The material chosen: standard shingle, architectural shingle and metal do not cost remotely the same

And for a 100 m² roof?

It is a common search, so let us do the maths together. 100 square metres is roughly 1,076 square feet, so about 10.8 squares of roofing.

But careful: is that 100 m² the roof surface, or the living area of the house? Because those are really not the same. A house with a 100 m² footprint and a medium-pitch roof can easily have 120 to 130 m² of actual roof surface.

That is exactly why I refuse to give a firm price over the phone. I can give you an honest range — and I do, below — but a precise figure without having seen the roof would be guesswork, and you would risk paying for it later in "extras".

The phone-estimate trap

If a contractor gives you a firm price over the phone without ever having seen your roof, ask yourself one question: what is it based on? At best, they are giving you an average. At worst, they are giving you a low number to win the contract, ready to revise it once work has started.

A serious quote comes after a visit, in writing, with the scope spelled out: tear-off included or not, debris removal, the exact shingle line, the workmanship warranty. With us, the quoted price is the final price — it only changes if we find a damaged deck under the old roof, and in that case we call you before doing anything.

And if one quote is markedly lower than the others, that is not necessarily a bargain. Compare what it includes before you compare the totals.