A wide flat roof is a drainage problem with a snow problem on top. East Flagstaff, AZ lies beyond Buffalo Park, where retail and redevelopment sites sit near Route 66 and East Huntington Drive. Flagstaff Mall, a 347,000 square foot single-story center that opened in 1979, sits on this side of town. Flagstaff's 90 to 97 inches of snow a year loads any broad roof out here, and snow piles in the lee of every taller wing and every added unit. We check the deck first, then the drains, then the seams.
Retail districts change a little at a time. A mall that adds a new wing, as Flagstaff Mall did in 2020, shows how a retail roof grows. A wing added to an older building gives the owner two roofs that may differ in age, slope and drainage, and the line where they meet is the weak spot. We map every tie-in on the sketch and check each one. The same method fits any retail building on the east side that has grown by additions.
Rooftop equipment adds to the pattern. A new tenant usually means a new unit, and every unit brings its own curb and lines. We record each unit by tenant space and check the curb flashing and the walk path for each. A leak report from a tenant can then be traced to the right section of roof without a long search.
A broad low-slope roof sends water a long way to a drain, and the slope toward each outlet is slight. When one clogs, a pond spreads across the deck. In winter the drain freezes and the pond turns to ice. We clear every drain and scupper on the fall walk, test the flow and measure any pond that stays more than a day after rain. Overflow scuppers get the same check, since they carry the water when a drain is shut. A drain and scupper review is the cheapest roof work on the list.
Heat tape helps where a drain freezes every year. It costs little against a pond on a wide deck. We list those drains in the plan, along with the drift lines and the lower decks to recheck after each big storm.
After the February 28, 2023 storm, parts of Flagstaff stood under 24.5 inches of snow by March 2, and the city tied several roof collapses to the load. Its watch list was short: ceilings that sag, trusses that bow, leaks that turn severe. Additions create steps in roof height. Snow slides from the higher roof onto the lower one and piles against the wall, so the lower deck sees a load far above the open field. We check the lower decks first. If a ceiling dips or a truss bows, call a structural engineer before a roofer.
Interior signs come first for most owners. A ceiling grid that no longer sits flat, a sprinkler pipe that has dropped and a crack that opens at a wall top all point to deck movement. Walk the space with the roof sketch in hand. Mark each sign. Match it to a spot on the roof. A cluster under one drift line says more than a single stain.
Sears closed in 2018, and a Hobby Lobby and an entertainment wing followed in 2020. A large space that sits empty between tenants has no one inside to notice a leak, so a roof over a vacant bay should be walked on a schedule, with drains cleared and ceilings checked. When a new tenant arrives, new rooftop units bring new curbs and new penetrations. Each is a seal to inspect. A big-box store roof gets the same attention when the tenant changes. We write each change into the roof file.
A 2007 report described a 28-acre city parcel near the Fourth Street bridge and Route 66 in east Flagstaff, where the city wanted multi-story mixed-use development reaching East Huntington Drive. Multi-story buildings change the roof questions. Taller walls throw longer wind shadows and build deeper drifts on adjacent roofs, and roofs above occupied floors need leak protection from the first day. If such buildings rise, nearby low roofs will see new drift patterns, and their owners should recheck the deck.
Planning ahead costs little. Owners beside parcels that may be redeveloped can photograph their roofs and decks now, record the current drift pattern and keep the file. If a taller neighbor changes the wind later, the before-and-after record shows what moved. A few photographs and a sketch are enough.
Repair fits a sound deck and dry insulation. A recover may fit a flat roof with one dry layer. Replacement fits wet insulation across wide areas or a failed seam system. A core and a moisture scan decide. For a center that stays open, occupied building reroofing splits the work into sections that are closed in each day. A commercial roof inspection starts the file. Cost drivers are area, access, deck, insulation and the number of penetrations.
Retail adds a calendar. Holiday weeks and weekends are the busy times, and roof work belongs in the quiet ones. We book large jobs for late spring through early fall, when the weather is dry and store traffic is lighter, and we keep a crew on call for winter leaks that cannot wait.
A core sample settles the recover question. It shows how many layers lie on the deck, how thick the insulation is and where water sits. We cut it, photograph it and patch the hole the same day.
Walk the roof in September, before the first hard freeze. Clear drains, check tie-ins and write a shoveling plan with plastic tools. Give us the address, the roof type and any past stain photos, and we will set the date.
Downtown Flagstaff has masonry parapets that collect drift, and Butler Avenue and Lone Tree Road has rooftop units that do the same on their lee sides. An east-side roof can show both problems at once.
Rank the work by load. First in line: roofs that fail the sag check and low roofs sitting under drift lines. Second in line: blocked drains and open tie-ins. A sound older roof is still walked once a year. The order spends money where the snow load is worst.
Two roofs of different age and slope meet there, and they move at different rates. The flashing or seam opens. We check every tie-in on the fall walk.
Walk it on a schedule, clear the drains and look at the ceilings below. Nobody inside will report a drip, so the walk is the only early warning.
It piles snow against the wall and loads the deck far above the open field. Check the lower deck for sag before and after big storms.
Yes, in sections. Each section is closed in daily, and noisy work is scheduled for early hours. The tenants get notice of the plan.
The building address, the roof type and any past reports or photographs of stains. We will walk the roof and report what we find.
Browse the services, roof systems and building types we work with across Flagstaff and nearby Arizona communities.
A walk of the roof with photos, findings and a written scope.
Active leaks, storm damage and blocked drains get a fast response.
Roofing across Flagstaff and nearby Arizona communities.