Detail work decides old brick roofs. A flat roof behind a masonry parapet has more corners than field. Every corner is a place for water to enter, and thaw cycles in Flagstaff, AZ work at them every spring. Soprema makes modified bitumen membranes, liquid-applied resins such as Alsan, and the insulation under both. Repairs and maintenance on these roofs are what we do. Resin suits the odd shapes. The sheet side suits big fields. We choose by the geometry of the roof in front of us.
Modified bitumen is a factory-made sheet of asphalt blended with rubber or plastic, laid in two plies and joined by torch, adhesive or self-adhesion. It resists punctures well and welds into the roof at the laps. Alsan is a liquid-applied resin that cures into a continuous film around pipes, curbs, drains and corners. It follows any shape with no joint. Insulation and cover board sit under both. A system can pair a sheet field with resin flashings, so the large areas are quick to lay and the awkward spots have no joints to fail.
A hybrid roof pairs sheet and resin. A big flat field can take a sheet. The perimeter, with its walls, drains and equipment, takes resin. The two meet at a lap that must be made carefully. We check that lap on every visit, because a hybrid roof leaks at the seam between its two halves more than anywhere else.
Asphalt stiffens in the cold. Flashings stiffen first because they are thin and sit on walls that move. A record low of minus 30 degrees F and freezing from late September make that stiffness a fact of life in Flagstaff. A cracked flashing at a parapet wall opens a path for meltwater. Liquid-applied resins stay flexible through temperature swings, which is why they are common at corners and penetrations. We test flashing by pressing and flexing it, look for hairline cracks and check the top edge where it ties into the wall.
City officials say several roofs came down after the storm that began February 28, 2023, by which point some areas of Flagstaff held 24.5 inches. The city's list of warnings was sagging ceilings, bowing trusses and severe leaks. Brick walls hold a roof edge up, but the deck between them still carries the snow. Drift lines pile behind parapets and mechanical wells, and ice dams form at cold edges when heat leaks from below. We mark every drift line, check the deck under it and look at the edge for staining. A snow plan names who goes up, which areas to clear first and which tools are allowed.
Old decks need special care under snow. An older deck may be wood boards or steel framing sized to earlier loads. The sag check happens from below, and an engineer is called if the framing is under stress. Do not shovel an old roof without that check.
Walk the roof in September. Clear the drains and scuppers. Check the parapet cap or coping, the counterflashing and the base flashing. Press the corners. Probe the laps on a modified bitumen field. Look for blisters, granule loss and exposed felt. Check every pipe, curb and drain for cracked resin or open boots. Look for stains on the inside face of the parapet wall, which show water running behind the flashing. Photograph each finding and mark the sketch. A flashing failure repair is the most common job on this kind of roof.
Interior walls show the story. A brown stain high on a masonry wall, white salts on brick and paint that bubbles all point to water behind the flashing. Walk the rooms below the parapet. Mark each sign on the roof sketch beside the matching flashing. The match saves hours on the roof.
Match the repair to the material. A torch-applied patch needs a sound bitumen base and safe working conditions. An adhesive patch needs a clean, dry surface. A liquid-applied repair needs a primed, compatible substrate and a mild day for cure. We prep, test a small area and then repair to the system's detail. Complex areas, like a cluster of pipes or an irregular curb, are good candidates for resin. A modified bitumen roof repaired this way holds through many thaw cycles when the flashing is sound. A skylight and penetration flashing rebuild follows the same logic.
Cost follows geometry. A broad field with few penetrations prices by area. A busy roof with many pipes, curbs and drains prices by the detail count. We list the count in the scope. The owner sees how much of the price sits in the field and how much sits in the corners, and can decide whether a resin upgrade at the worst corners is worth it.
The Railroad Addition Historic District downtown covers 17.8 acres and was listed on the National Register in 1983. Its historic commercial buildings include the Weatherford Hotel, Monte Vista Hotel, Babbitt Brothers Building and Riordan Building. After fires, an 1897 ordinance required brick, stone or iron, so older downtown roofs sit on masonry buildings. Every building along Santa Fe Avenue faces the railroad tracks. Old masonry and parapets mean many details. Each building in Downtown Flagstaff is walked on its own, and a hotel roof brings occupant concerns that an office or shop does not.
Mike's Pike is the contrast. It is a half-mile stretch of pre-1934 Route 66, mostly industrial, with boxy metal, wooden and concrete buildings. A broad, simple roof of that type could take a sheet quickly, and the walk decides it. The same snow, the same thaw, a different geometry. That is why the choice between sheet and resin follows the roof and not the brand.
Cold-applied and resin systems avoid open flame and strong odor, which suits occupied building reroofing downtown, where hotels, offices and shops stay open. Schedule the work for dry stretches. A winter leak gets a temporary patch that stops the water, and the patch goes on the sketch. Do the fall walk and the drain clear ahead of October. Flagstaff's 2018 IBC and energy code, with the 2019 local amendments, apply to any reroofing. Johns Manville and GAF make bitumen and single-ply sheets too, and the roof in hand picks between them.
A resin that cures into a continuous film around pipes, curbs and corners. It follows any shape and has no seams between pieces, so it suits complex details.
Only as a temporary patch. Torches and adhesives need workable weather. We stop the water, mark the patch and make the permanent repair in a dry window.
Mortar joints age, the counterflashing pulls away and thaw cycles drive water in. Fixing the wall joint and the flashing together solves most of it.
When installed correctly on a clean, dry base, yes for most uses. The choice often comes down to fire safety and odor in an occupied building.
When insulation is wet across wide areas, laps fail in rows or the surface is worn to the base sheet. A core and a moisture scan tell the story.
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.