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== Commercial Roof Replacement ==

'''Commercial roof replacement''' is the complete removal and reinstallation of a commercial building's roofing system, typically costing $5–$16 per square foot installed ($250,000–$800,000 for a 50,000 sq ft building) and taking two to eight weeks depending on size, system, and weather. A new commercial roof lasts 20–40 years by system type, and replacement becomes the economical choice when a [[Commercial Roofing|commercial roof]] reaches the end of its service life, has widespread wet insulation, or generates recurring leaks that repairs no longer control. Building owners choose between three levels of intervention: full tear-off replacement, a recover (overlay) of a new membrane over the existing roof, or restoration with a fluid-applied coating.

== How Much Does Commercial Roof Replacement Cost? ==

Installed cost depends primarily on the roofing system, insulation requirements, tear-off scope, building height, and rooftop complexity (HVAC units, penetrations, parapets). Typical installed ranges for full replacement:

{| class="wikitable"
|-
! System !! Installed Cost (per sq ft) !! Expected Lifespan !! Notes
|-
| [[TPO Roofing|TPO]] || $5–$9 || 20–30 years || Most popular new commercial system; reflective and energy-efficient — see [[TPO Roofing Cost]]
|-
| [[EPDM Roofing|EPDM]] || $5–$9 || 25–30 years || Proven rubber membrane; strong cold-climate record
|-
| [[PVC Roofing|PVC]] || $6–$11 || 20–30 years || Best chemical and grease resistance; restaurants, factories
|-
| [[Modified Bitumen Roofing|Modified bitumen]] || $5–$10 || 20–25 years || Multi-ply asphaltic redundancy; handles foot traffic well
|-
| [[Built-Up Roofing|Built-up (BUR)]] || $6–$10 || 20–30 years || Heavy, durable, gravel-surfaced; fewer installers today
|-
| [[Metal Roofing|Metal (standing seam)]] || $8–$16 || 40–60 years || Highest upfront cost, longest life; suits low-slope and sloped profiles
|}

Add roughly $1–$3 per square foot if code upgrades require new or thicker insulation (most energy codes now mandate R-25 to R-30 above deck), and more if the structural deck needs repair after tear-off. Tear-off and disposal of the old roof typically adds $1–$2 per square foot, more for multiple existing layers or wet materials.

== Should You Replace, Recover, or Restore? ==

Full replacement is not the only option, and the right choice depends on the condition of what's already on the roof:

* '''Full tear-off replacement''' ($5–$16/sq ft): Removes everything down to the deck. Required when insulation is widely saturated, the deck needs inspection or repair, or two roof layers already exist (most codes prohibit a third). It is the most expensive option but resets the roof completely and qualifies for the longest warranties.
* '''Recover / overlay''' ($3–$7/sq ft): A new membrane is installed over the existing roof, usually with a separation board. Permitted only when there is a single existing roof layer and a moisture survey confirms the insulation is dry. Saves tear-off and disposal costs and shortens the schedule, but hides the old roof and may reduce warranty terms.
* '''Restoration / coating''' ($2–$4/sq ft): A fluid-applied silicone or acrylic coating restores a structurally sound but weathered membrane, adding 10–20 years. The cheapest path and often classified as maintenance for tax purposes, but it cannot fix wet insulation or failed seams. See [[Commercial Roof Restoration]] and [[How to Apply Roof Coating to a Flat Roof]].

A pre-project moisture survey — infrared or capacitance, as described in [[Commercial Roof Inspection]] — is the deciding input. As a rule of thumb, under 25% wet insulation favors recover or restoration with selective wet-area replacement; over 25–30% wet favors full tear-off.

== How Long Does Commercial Roof Replacement Take? ==

Plan on two to eight weeks of on-site work for most projects. Typical production rates run 5,000–15,000 square feet per day for tear-off-and-install on straightforward roofs, slower for high buildings, congested rooftops, or occupied-building constraints. Add two to six weeks before mobilization for material lead times, permits, and crane scheduling.

For occupied buildings, experienced contractors phase the work to limit disruption:

* '''Section-by-section tear-off''': Only the area that can be made watertight the same day is opened up, so the building is never exposed overnight.
* '''Scheduling around operations''': Noisy work (tear-off, fastening into the deck) can be scheduled before business hours or over weekends above sensitive areas like offices, clinics, or classrooms.
* '''Odor and air-intake management''': Adhesives, torch work, and hot asphalt require shutting or filtering nearby HVAC intakes; low-VOC and self-adhered systems reduce this issue.
* '''Protection and logistics''': Staging areas, debris chutes, crane lift windows, and protected entrances are agreed in advance so tenants, customers, and deliveries can continue normally.

Most occupied buildings remain fully operational throughout a phased replacement. Discuss phasing, work hours, and interior protection explicitly during bidding — [[How to Hire a Commercial Roofing Contractor]] covers what to require in the contract.

== How Do You Choose a Replacement Roofing System? ==

Match the system to the building rather than defaulting to the cheapest bid:

* '''Climate''': Reflective TPO and PVC reduce cooling loads in hot climates; EPDM and modified bitumen have long track records in freeze-thaw climates. Canadian owners should see [[Choosing the Right Commercial Roofing System in Canada]].
* '''Rooftop use and traffic''': Heavy HVAC service traffic favors modified bitumen, BUR, or thicker (80-mil) single-ply membranes with walkway pads.
* '''Chemical exposure''': Restaurant grease exhaust and industrial chemicals call for PVC.
* '''Budget vs horizon''': Owners holding the building long-term often justify metal or premium membranes; shorter horizons favor TPO or EPDM.
* '''Slope and structure''': Existing slope, drainage, and deck capacity constrain options — an overview of all major systems is at [[Commercial Roofing Systems]] and [[Flat Roofs]].

Energy performance matters too: cool, reflective membranes can cut summer cooling costs measurably, a topic covered under [[Energy-Efficient Roofing Systems]].

== What Warranty Should You Get With a Commercial Roof Replacement? ==

Commercial roof warranties come in two distinct layers, and the difference matters at claim time:

* '''Manufacturer system warranties''' (10, 15, 20, 25, or 30 years): Cover the membrane and, in better versions, the full system. The strongest form is an '''NDL (No Dollar Limit) warranty''', under which the manufacturer covers the full repair cost of covered defects — including labor — for the entire term, with no proration. NDL warranties require installation by a manufacturer-certified contractor and a manufacturer inspection at completion.
* '''Contractor workmanship warranties''' (typically 2–5 years): Cover installation errors, which cause most early failures. A short workmanship warranty from an uncertified installer is a red flag on a six-figure project.

Read the exclusions: ponding water, unauthorized repairs or alterations, missed maintenance, and added rooftop equipment commonly void coverage. Most NDL warranties also require documented periodic maintenance — a working [[Commercial Roof Maintenance|commercial roof maintenance]] program is effectively a warranty condition, not an option. For warranty mechanics in general, see [[Roof Warranties Explained]] and [[What Voids Your Roof Warranty]].

== Quick Facts ==

{| class="wikitable"
|-
! Metric !! Value
|-
| Installed cost (full replacement) || $5–$16 per sq ft by system
|-
| Recover (overlay) cost || $3–$7 per sq ft
|-
| Restoration (coating) cost || $2–$4 per sq ft
|-
| Typical project duration || 2–8 weeks on site
|-
| New roof lifespan || 20–40 years (metal up to 60)
|-
| Strongest warranty type || Manufacturer NDL, 20–30 years
|}

== Frequently Asked Questions ==

=== How much does commercial roof replacement cost per square foot? ===

Full commercial roof replacement costs roughly $5–$16 per square foot installed: TPO and EPDM run $5–$9, PVC $6–$11, modified bitumen $5–$10, built-up $6–$10, and standing seam metal $8–$16. Tear-off, added insulation for code compliance, building height, and rooftop congestion push projects toward the upper end.

=== Can a new commercial roof be installed over the old one? ===

Often, yes. A recover (overlay) is allowed when only one roof layer exists and a moisture survey confirms the insulation is dry. It saves $1–$2 per square foot in tear-off and disposal and shortens the schedule. Two existing layers, wet insulation, or a deteriorated deck require full tear-off instead.

=== How long does it take to replace a commercial roof? ===

Most commercial roof replacements take two to eight weeks on site, with crews completing roughly 5,000–15,000 square feet per day depending on system and complexity. Phased tear-off keeps the building watertight every night, so occupied buildings normally continue operating throughout the project. Add several weeks for permits and material lead times.

=== What is an NDL roof warranty? ===

NDL stands for No Dollar Limit. Under an NDL manufacturer warranty, the manufacturer pays the full cost — materials and labor — to repair covered defects for the entire 10–30 year term, without proration or a payout cap. It requires a certified installer, a final manufacturer inspection, and usually documented ongoing maintenance.

== Find a Roofing Contractor ==

Ready to hire a professional? Browse the [https://roofs.wiki/roofing-directory/ roofs.wiki roofing contractor directory] — an independently researched, BBB-verified ranking of the top roofing companies across the US and Canada, including [https://roofs.wiki/roofing-directory/calgary/ Calgary], [https://roofs.wiki/roofing-directory/toronto/ Toronto], [https://roofs.wiki/roofing-directory/vancouver/ Vancouver], and many more cities.

== Related Resources ==

* [[Commercial Roofing]]
* [[Commercial Roof Repair]]
* [[Commercial Roof Maintenance]]
* [[Commercial Roof Inspection]]
* [[Commercial Roofing Systems]]
* [[Roof Warranties Explained]]

[[Category:Commercial_Roofing]]

Commercial Roof Replacement - Revision history

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