Best Flat & Low-Slope Roofing Contractors in London

Flat and low-slope roofing in London relies on membrane systems — TPO, EPDM, modified bitumen, and built-up roofing — common on commercial buildings and many modern homes. The 5 contractors below were selected from our full London top 10 as the strongest for flat & low-slope work, ranked by experience, manufacturer certifications, BBB standing, and verified reputation.

London, Ontario occupies a transition zone between Lake Huron's moderating influence and the inland continental climate of Southwestern Ontario. The city receives significant snowfall and extended periods of freeze-thaw cycling — particularly in the March-April shoulder season when daily temperatures cross zero repeatedly — that put flat and low-slope roof membranes under sustained thermal stress. Fully adhered EPDM has a long track record in the London market precisely because of its low-temperature flexibility, though TPO with heat-welded seams has become the dominant choice for new commercial construction across the Forest City.

London's building stock includes a substantial inventory of flat-roofed commercial and institutional buildings along Richmond Street and in the downtown core, as well as multi-unit residential structures across neighborhoods like Old North, Byron, and Wortley Village. The city's role as a regional hub — drawing commercial and institutional investment from across Southwestern Ontario — means its commercial roofing contractors have experience with projects ranging from small retail flat sections to large hospital and university campus roofscapes. Courtney Roofing and AM Group Exteriors, both with deep London roots, represent the type of multi-generation experience that a significant flat-roof project warrants.

How many flat & low-slope roofing contractors are in London?

Our directory lists 5 independently verified flat & low-slope roofing contractors serving London, Ontario, ranked by experience, certifications and reputation. AM Group Exteriors (AM Roofing Solutions) is ranked #1. There are no paid placements.

How do I choose a flat & low-slope roofer in London?

Confirm licensing and insurance for Ontario, ask for flat & low-slope project references in London, get multiple written quotes, and check each contractor's BBB standing. Every company listed here has been independently researched.

How does London, Ontario's climate affect the choice between EPDM and TPO for flat roofing?

Both perform well in Southwestern Ontario's climate. EPDM has the longer track record in London's commercial market and is highly regarded for its low-temperature flexibility during the March freeze-thaw period. TPO with heat-welded seams is now the more common choice for new commercial construction because the weld eliminates the lap-seam adhesive bond that EPDM relies on and that can be sensitive to installation conditions. For recover over an existing EPDM substrate, compatibility between the existing membrane and the new system's adhesive must be confirmed with the manufacturer before installation.

What permits are required for flat-roof replacement in London, Ontario?

The City of London requires a building permit for re-roofing work that changes the roof assembly — insulation, membrane type, or structural elements. A like-for-like membrane replacement at the same thickness and configuration may qualify for a simplified permit category, but this should be confirmed with the City of London Building Division before work begins. Projects on heritage-designated commercial buildings in the downtown core may also require heritage permit review before any roofline changes are approved.

How long should a flat roof last in London's climate with proper maintenance?

A properly installed and maintained fully adhered membrane system should achieve a substantial service life in London's climate — meaningfully longer than a mechanically fastened system, which is more vulnerable to the thermal stress of Southwestern Ontario's freeze-thaw cycling. The variables that most affect actual service life are installation quality, drain maintenance, and whether the roof receives regular foot traffic that accelerates membrane wear. Biannual inspections — once in spring and once in autumn — and prompt attention to minor seam issues before they enlarge are the most cost-effective maintenance strategy.