Pricing a roof in Alberta and BC: what changes from the Ontario numbers

Very little of the method changes when you price a roof in Alberta or British Columbia instead of Ontario: the roof area, the squares, the edge lengths and the waste factor come off the measurement the same way. What changes is everything you multiply them by, and the tax line under the subtotal: Ontario quotes carry 13 % HST, Alberta quotes carry 5 % GST and no provincial sales tax, and BC has 5 % GST plus a 7 % PST that follows its own rules for contractors.

What carries over, and what you rebuild#

A roof measured from satellite imagery, or from your own drone or phone photo, gives the same squares in Red Deer as in Ottawa. If you measure yourself in the RoofStruct builder, the drawing and the PDF report are the same wherever the job is.

The tax line, province by province#

These rates are from the Canada Revenue Agency's GST/HST rate page, read on 30 October 2026:

• Ontario: 13 % HST, one line on the quote.
• Alberta: 5 % GST, no provincial sales tax. One line, and the smallest one.
• British Columbia: 5 % GST, and a 7 % PST administered by the province.

BC is the one to slow down on. The province has specific PST rules for contractors who supply and install materials that become part of a building, and those rules decide whether PST shows up as a line on your quote or is paid on the materials and carried inside your cost. Read the province's PST guidance for contractors before your first BC quote, and set your template to match. Do not copy an Ontario template that adds one tax percentage to the bottom.

For the Québec version of the same question, see pricing a roof per square metre in Canada, which works the TPS and TVQ on a quote.

Weather changes the scope, not the measurement#

The roof does not get bigger out west, but the list of what goes on it can change.

Alberta. Hail is a regular summer story in parts of the province, and homeowners there often ask about impact-rated shingles. That is a material choice to price as an option, not a change to the squares. Southern Alberta also swings between thaw and freeze through the winter, so eave protection and ventilation get more questions from customers than they would in many Ontario towns.

Coastal BC. Rain, not snow, is the long season. Underlayment choice, moss on north faces and wet-weather scheduling all affect labour days. On a job in the Lower Mainland or on Vancouver Island, plan for days lost to rain the way an Ontario crew plans for snow days.

Interior BC and the mountain towns. Heavy snow and ice at the eaves are back in the picture, along with steeper roofs on chalet-style houses. Steep faces change the labour rate, not the measurement.

Worked example: one house, three provinces#

Take a measured hip roof with 2,150 ft² (199.7 m²) of roof area. A roofing square is 100 ft², about 9.29 m², so that is 21.5 squares. With a 10 % waste factor you order 23.65 squares, rounded up to 24 squares (about 223 m²), or 72 bundles of a three-bundle-per-square laminate. The eaves run 168 ft (51.2 m) and the rakes 0 ft, because it is a hip roof.

All of that is identical in Mississauga, Calgary and Kelowna. Now say your rates put the job at a $20,000 subtotal before tax. That number is an illustration for the tax maths, not a market price; build your own from local rates.

Same subtotal, a $1,600 gap between the Ontario and Alberta totals, purely from tax.

Where you trip#

• Copying the HST line. An Ontario template that adds 13 % on top of an Alberta quote overcharges the customer by 8 points of tax you have no right to collect.
• One tax line in BC. Adding 12 % to the bottom of a BC quote ignores the contractor PST rules. Check them first.
• Ontario labour rates in a tight market. Alberta and BC crews can be booked weeks out in season. Price what it costs to get a crew there, not what it cost at home.
• Forgetting freight and travel. Rural Alberta and interior BC jobs can sit far from the supplier's yard. Delivery charges and crew travel belong on the estimate.
• Re-measuring instead of re-pricing. The squares did not change. Keep the measurement, change the rate card.
• Mixing units on the order. A western supplier may quote in either system. Convert once, as shown in roof squares vs square metres, and stay there.

FAQ#

Do I charge PST on a roofing job in Alberta?#

No. Alberta has no provincial sales tax, so a quote there carries 5 % GST only, according to the Canada Revenue Agency's rate page read in October 2026.

Is the tax on a BC roofing quote just 12 %?#

Not necessarily. GST is 5 %, and PST is 7 %, but BC's contractor rules decide how PST applies to supply-and-install work. Read the province's PST guidance for contractors before you set up your BC quote template.

Does the roof measurement change between provinces?#

No. Roof area, squares, edges and waste come from the roof itself. The province changes your rates, your scope options and your tax line.

Can I get the measurement without a site visit in Alberta or BC?#

Yes. You can measure it yourself from satellite imagery for free, or order a done-for-you report through RoofStruct reports, usually delivered within 4 hours (turnaround can vary with volume and complexity). Pitch and anything under the shingles still need a check on site.

Sources#

Checked Oct 2026:

• Canada Revenue Agency, GST/HST rates by province