It is the first question every building owner asks, and the honest answer is that no two roofs cost the same. What we can do is show you exactly how commercial flat roof pricing works in London, so you can budget with real numbers instead of a guess.
Unlike a house, a commercial roof is quoted on its area and the system going on it. As a broad guide for Southwestern Ontario, a full single-ply flat roof replacement (tear-off and new membrane) commonly lands somewhere in the range of $8 to $16 per square foot installed. A 10,000 square foot warehouse roof and a 2,000 square foot storefront are very different projects, which is why the total can range from a few thousand dollars for a small section to six figures for a large industrial roof. Treat that range as a starting point for budgeting, not a quote. The only way to get a real number is to look at the actual roof.
A targeted repair can run from a few hundred dollars for a small flashing fix to a few thousand for a larger section, and it is often the smart call when the rest of the roof has good years left. When you are paying for the same leak twice a year, or the insulation is saturated across the roof, a full replacement is the cheaper path over time. We will tell you honestly which one your building needs.
On a flat roof, the membrane rarely fails first. The details do, the seams, flashings, and drains. A rock-bottom quote usually saves money by thinning those details or skipping the certified install, and that shows up as leaks a few winters later in London's freeze-thaw climate. The quote that spells out the system, the thickness, and the warranty in writing is the one to trust.
We come out, measure the roof, check the deck and drainage, and give you a written, itemized quote with the system and warranty spelled out. No pressure, no fixed price over the phone, just an honest assessment you can budget from. Serving London, Strathroy, St. Thomas, Woodstock, and Middlesex County.