--- title: "Could This Summer’s Heat Become a Winter Commercial Flat Roof Leak?" date: 2026-10-06 author: "Melisha" categories: - name: "Flat Roofs" url: "/category/flat-roofs.md" --- # Could This Summer’s Heat Become a Winter Commercial Flat Roof Leak? [![Rayco Template (2)](https://www.raycoconstruction.com/wp-content/uploads/2026/10/Rayco-Template-2-300x300.png)](https://www.raycoconstruction.com/wp-content/uploads/2026/10/Rayco-Template-2.png) Minnesota had an unusually hot summer, and that heat may have accelerated deterioration on aging commercial flat roofs. According to the Minnesota DNR, July 2026 was approximately 4.3°F above normal statewide, making it one of Minnesota’s hottest Julys on record. The Twin Cities also experienced 10 consecutive days at or above 90°F. [**Read more about Minnesota’s summer heat from the Minnesota DNR.**](https://www.dnr.state.mn.us/climate/journal/heat-mid-july-2026.html) Dry weather can give building owners a false sense of security. Without rain, we aren’t thinking about roof leaks, water damage or unhappy tenants. Rayco’s team is already seeing failures on aging commercial roofs that may not become obvious until later this fall or winter. Heat causes roofing materials to expand, while cooler temperatures cause them to contract. Fall’s dramatic temperature swings increase that movement. Aging built-up roofs can crack and delaminate, while older single-ply membranes can become brittle, shrink and tear. ### **Winter Makes Roof Repairs Harder** Once snow and ice arrive, even a relatively simple roof repair becomes more difficult and expensive. Crews may need to shovel snow, remove ice or treat slippery areas just to reach the damaged membrane. On roofs with ponding water, those areas can become thick ice during the winter. Meanwhile, melting snow can find its way into deficiencies that went unnoticed during the dry summer months. ### **Get Ahead of the Leak** Now is the time to have your commercial flat roof assessed and address vulnerable areas before winter. Not every aging roof needs to be replaced. Finding and repairing small problems now can help prevent a much larger — and more expensive — problem this winter. Rayco Construction specializes in commercial flat roofing throughout the Twin Cities. Contact our team to schedule a roof assessment before the snow arrives. ## Frequently Asked Questions ### **Can a commercial flat roof have problems even if it isn't leaking into the building?** Yes. A commercial roof can have failing seams or flashings, membrane deterioration, or other vulnerable areas without showing an interior leak. Water may already be getting into the roofing system and damaging insulation or the roof deck before it ever reaches the inside of the building. By the time you see a ceiling leak, the problem may have been developing for some time. ### **Why would my flat roof leak when there is snow but not when it rains?** Snow can hold meltwater against a flat roof much longer than a typical rainstorm. Think about stepping into deep, slushy snow and watching water fill in around your boot. A similar thing can happen on a roof: snow becomes saturated with water and keeps that water sitting directly over vulnerable areas. Snow and ice can also restrict drains and scuppers. Instead of draining normally, water can become deeper and remain on the roof longer. A small opening that may not leak during a normal rain can become a problem when it is exposed to standing water for an extended period. ### **Does summer heat affect commercial roofs?** Yes. Heat and UV exposure contribute to the normal aging and weathering of commercial roofing materials. High temperatures can be especially hard on older roofs and roofs that already have vulnerable seams, flashings, or membrane deterioration. Those weaknesses may not become obvious during a hot, dry summer. They often show themselves later when fall temperature swings, rain, snow, and freeze-thaw conditions put additional stress on the roof. ### **Does a roof inspection mean Rayco will tell me I need a new roof?** Depending on what we find, our recommendation may be a repair, preventative maintenance, continued monitoring, or planning for a future roof replacement. If your roof doesn’t need to be replaced yet, we’ll tell you that. ### Know What’s Happening Before the Snow Flies** The fact that your commercial flat roof made it through a hot, dry summer without leaking is good news. It just shouldn’t be the only information you have about its condition. If you have an aging flat roof, a history of repairs, or simply aren’t sure how your roof is holding up after another year of Minnesota weather, Rayco Construction can help you understand what you’re working with before winter arrives. **Schedule a commercial roof inspection with Rayco Construction.** ### [Request an Inspection](https://www.raycoconstruction.com/contact-us/estimate/)