What is involved
Commercial Roof Replacement: what to expect
A replacement is the point at which you can fix everything the original roof got wrong. Drainage
that never worked, insulation below current code, edge metal that lifts in a gust front, penetrations that were never
detailed properly, all of it is on the table exactly once. Treat it as a design exercise, not a shopping exercise.
What belongs in the scope
- Tear-off versus recover, and the code limit on existing layers in your jurisdiction.
- Deck inspection and an allowance for deteriorated deck, stated as a unit price rather than a surprise.
- Insulation type and R-value, meeting the energy code adopted locally for this climate zone.
- Tapered insulation or crickets to eliminate ponding, particularly behind curbs and at drains.
- Perimeter and edge metal designed for wind uplift, with the securement method specified.
- Coordination for rooftop equipment: mechanical disconnects, curb raising, crane or lift access.
- The warranty, who issues it, its term, what it covers, and what voids it.
Cost drivers
Installed cost for commercial low-slope work across the industry commonly falls in a broad range per square foot
depending on system, insulation thickness, tear-off, deck condition, building height, access and how much of the work
has to happen at night. Two honest bids on the same building can differ substantially for entirely legitimate
reasons, which is exactly why the scope has to be written down before the prices are compared.
Occupied buildings
Retail, medical, restaurant and office buildings usually require phased work, daily dry-in of any open area, odour
and noise management, and often night or weekend scheduling. Say so up front; it is much cheaper to price than to
renegotiate.
