1. Article Body
On a warehouse, cost per square foot is lower than almost any other building type and the total is larger than almost any other. The variable that moves the number most is not the roof, it is the operation beneath it.
Costs vary by market and building, so this explains the structure rather than quoting figures.
Where scale helps
Setup, mobilization and overhead spread across a very large area, so cost per square foot falls.
Simple geometry helps too. Most warehouses are large rectangles with relatively few penetrations per square foot compared with a restaurant or an apartment building.
Where scale hurts
Absolute quantity. Insulation to current energy code across a large area is a very large material cost.
Tear off and disposal volume. Disposal is priced by weight or volume and both are substantial.
Schedule length, which extends every temporary condition and every exposure to weather.
The phasing constraint
This is the dominant variable.
A roof cannot be opened above occupied racking. Phasing therefore follows where product can be moved to, and that is a warehouse operations question rather than a roofing one.
A building that can clear large bays sequentially reroofs efficiently. A building running at full capacity with no swing space reroofs in small sections at a significant premium, or waits.
Establish with operations what can be cleared, in what size, and for how long, before anyone prices the work.
Skylights
Decide whether skylights are replaced, removed or retained.
Replacing them at reroof costs far less than doing it separately later, and aged panels are both a leak source and a fall hazard. Retaining old panels under a new roof is usually a false economy.
Removing them entirely changes the lighting design and the energy model, so it is a decision for the operator rather than the roofer.
Uplift upgrades
Edge metal and perimeter fastening to current standards. Inexpensive relative to total cost and the single best value item in most warehouse reroofs.
Fire protection coordination
Sprinkler piping supported from the structure means coordination, possible impairment periods, notification and fire watch. Budget the coordination time.
Deck and structure
Deck condition is unknowable until open. On a metal deck, corrosion under a chronically wet area is common and the repair is disruptive.
Comparing bids
Require a common written scope covering system and specification, insulation and code compliance, tear off and disposal, skylight treatment, edge metal and perimeter upgrade, deck allowance with a unit rate, phasing plan tied to the operations constraint, fire protection coordination, and protection of goods below.
A bid well below the others on a warehouse almost always assumes an easier phasing plan than the building will permit.
