Flex and Light-Industrial Roofing in Dearborn, MI
A flex building is a roof that several tenants have each altered a little. One added an exhaust fan, another a condenser, a third ran conduit to a sign, and each cut a hole in the same membrane. The city of Dearborn, MI reports that manufacturing, education and health care, and professional, scientific and management services supply over 70 percent of local jobs, and flex space blends office frontage, shop space and rear loading for businesses in those sectors.
The roof therefore has to be read as a record of what tenants did to it. The first deliverable is a plan that lists every penetration by bay number, shows the membrane type for each section and marks the penetrations that look added after the roof went on.
Penetrations by Bay
We count what is on the roof: exhaust fans, rooftop units, vents, conduit runs, condensate lines, antenna mounts and capped holes where a tenant left. Each gets a number, a photograph of the flashing and a note on its condition. Field-cut penetrations are more likely to have improvised seals, so we mark them for a closer look. An unused penetration that was never closed is a common leak source on a shared roof.
With the plan in hand, rooftop equipment curbs and supports are checked for fastening, flashing height and pitch pockets, and the abandoned items are removed and patched. The manager receives a list of findings by bay, so the cost of a defect can be traced to the tenant that created it, where the lease allows.
Condensate lines get their own check. A condenser or rooftop unit that drains onto the membrane leaves a stain and wets the same patch every day, which erodes the surface under the discharge. We record where each line ends and propose piping it to a drain or a splash pad, which costs little next to the membrane damage it prevents. Conduit runs on blocks are checked too, since a block that sits on bare membrane wears through in time and needs a pad beneath it.
Roof Access and Walkway Pads
Uncontrolled roof access damages membranes. A tenant's service vendor walks across the roof with a tool bag, drags a ladder and leaves a puncture. We record the access points, the routes and the condition of the membrane along them, and we propose walkway pads where traffic is steady. A locked hatch with a log of who enters is a modest control that protects the roof.
When several tenants share a roof, the manager needs a way to warn them before work begins. The schedule names the bays affected each day, the hours of noise and the contact on site. Rear loading doors stay usable because the lift and the dumpster are staged at the side of the property.
Fall protection follows the same logic. A low flex roof still has an edge, and a vendor who walks to a unit near the edge is exposed. The plan marks warning lines or guardrail positions on the routes vendors use, and the manager receives a short rule sheet for them. Lease turnover is a good moment to hand it over, together with the roof access log.
Turnover also brings a chance to inspect before new equipment arrives. When a bay is empty, we walk its roof section, close any unused penetration and note the curb condition for the next tenant.
Where Flex Space Fits in the Metro Area
Nearby cities describe their own light-industrial and flex stock: Southfield identifies Central Business Center I and II and Bridge Street Industrial Park as light-industrial districts serving manufacturing, research and technology-oriented businesses, and Garden City locates its main industrial land north of Ford Road between Venoy and Moeller roads.
Buildings in Garden City or Southfield raise the same penetration questions as Dearborn flex space, and each roof is inspected as it stands. A bay with heavy users resembles a manufacturing plant, and bays used for storage and loading behave like a warehouse.
Repair, Recover or Replace on a Shared Roof
A flex roof often has sections of different ages from additions or earlier partial repairs. The moisture map shows which sections are wet. A recover over a dry, sound section is a reasonable way to extend service, while a wet section needs tear-off in that area. Dividing the building by section lets an owner replace what has failed and defer what has not, with the boundary documented. A TPO membrane welds cleanly around many small penetrations.
The tie-in between old and new sections is drawn on the plan. It must shed water, allow for expansion and stay accessible for later inspection. A poorly drawn tie-in tends to become the next leak.
Drainage on a shared roof is checked at the same visit. Interior drains sit at the low point of each bay and perimeter scuppers at the rear. We clear the drains, measure the depth of any pond after a dry spell and trace its cause: a drain set high, a blocked outlet, a deflected deck or insulation that has compressed. The fix may be a cleaned outlet or tapered insulation, and the update prices both.
Snow, Drainage and the Wet Season
The Dearborn station logs 35.05 inches of precipitation a year, 30.8 of them snow, and Detroit's normals put January snow at 14 inches. Flex roofs usually have interior drains at low points of each bay and perimeter scuppers at the rear. Debris collects at the scuppers behind loading areas, and standing water at a low drain can sit for days after a storm. We measure the water, clear the drains and propose tapered insulation or an added drain where ponding persists.
Snow loads need site-specific checks. On a replacement, the 2021 building code (in force since April 9, 2025) and the commercial energy code (in force since April 22, 2025) may change insulation requirements, and the local enforcing authority confirms which provisions apply before insulation is priced.
Closeout and Portfolio Records
The closeout file lists each bay with its roof section, the penetrations removed or repaired, the new flashing details, the access rules adopted and the next inspection date. When the owner manages several buildings, the same format fits into a multi-site roof program, so the buildings can be ranked on one schedule.
Warranty papers and inspection conditions are filed with it. A manufacturer warranty may require a yearly walk and prompt reporting of damage, and an unrecorded repair by a tenant's vendor can create a dispute later. The file lists dates and conditions so the manager knows what must be done and when.
Commercial Roofing Questions
How do you trace a leak when several tenants share one roof?
Every penetration is numbered on a plan by bay, and each interior stain is matched to the nearest roof detail. The pattern usually points to one added vent, curb or conduit run, and the findings name it.
Should one tenant's equipment affect everyone's roof cost?
The findings are reported by bay so the manager can see where defects began. Whether a cost is recovered from a tenant depends on the lease, which the manager holds.
Can a recover be used over wet sections?
Not over wet insulation. The moisture map sets the boundary, wet areas are removed and dry areas can be recovered, with the tie-in drawn on the plan.
What stops service vendors from damaging the membrane?
Walkway pads on the regular routes, a locked hatch with an access log and a rule that vendors report damage. The roof plan shows which paths are approved.
What records help during a sale or refinance?
A section-by-section plan, dated photographs, moisture findings and the next inspection date. A buyer can price the roof without a walkthrough.
Schedule a flex building roof inspection
Send the bay layout, the tenant list with roof access contacts and any repair history. We will inspect the roof, document every penetration by bay with photographs and written findings and give you a sequence that keeps loading doors working.
