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How Much Does a New Commercial Roof Cost? 

One of the most common—and most understandable—questions we hear in the commercial roofing industry is: “How much will my new roof cost?” 

It seems like it should be a straightforward answer. But the truth is, the cost of a new commercial roof depends on a wide range of variables. Some of these are visible when you’re standing on the roof. Others are hidden beneath the surface but can have an even greater impact on the final price. 

At Weather Shield Roofing Systems™, we’ve been guiding commercial building owners, property managers, and investors through these decisions for over 40 years. In this blog, we’ll break down the major factors that affect the cost of a new roof—so you can move forward with clarity and confidence. 

The Visible Components: What You Can See from the Roof

Let’s start with what’s most obvious—the things you can see when you’re standing on the roof. These make up a large part of your roofing investment, and they include:

1.) Roofing Material Type

The first and biggest driver of cost is the type of roofing material you choose. Each has its own pros and cons. Most low-slope commercial roofs use one of three main membrane types: 

• EPDM (rubber) – known for its durability and flexibility 

• TPO (thermoplastic polyolefin) – popular as a cost effective, energy efficient solution.

• PVC (polyvinyl chloride) – strong, chemical-resistant, and highly reflective 

2. Material Thickness and Warranty Length

With low-slope roofing, the thicker the membrane, the longer it lasts—and the longer the warranty. 

• 45 mil membranes: typically offer a 15-year warranty 

• 60–90 mil membranes: may offer 20- to 30-year warranties 

The price difference between a 15-year and a 30-year membrane is often $1 to $2 more per square foot. That might not seem like much, but it adds up quickly—and it’s a strategic investment if you plan to own or manage the building long-term.

2.) Roof Complexity

Next, consider how “busy” the roof is. A wide-open roof is faster and cheaper to install. But roofs with lots of features—like skylights, HVAC units, walls, drains, or multiple corners—require more materials, more labor, and more detail work. 

The more penetrations, slope changes, and transitions on your roof, the more complex (and costly) the installation becomes.

3.) Attachment Method

All roofing systems need to be attached in some way. There are three common methods: 

• Fully adhered – glued down for maximum wind resistance 

• Mechanically fastened – screwed in place through the insulation 

• Ballasted – held down by gravel or pavers 

Each method has its pros and cons, and the best choice depends on your building’s structure, location, and long-term goals. We cover this more in our blog: Which Flat Roof Attachment Method is Right for Your Commercial Roof? 

The Hidden Components: What’s Beneath the Surface?

This is where things get more complicated—and where costs can rise quickly. The condition and composition of your roof assembly (everything underneath the membrane, including insulation and structure) can significantly affect the final price.

• Multiple Roof Layers: If your building already has two layers of roofing, building codes require that all layers be completely removed before a new one can be installed.
  • That’s a big deal—because tear-offs are labor-intensive, time-consuming, and create extra disposal costs. A roof that needs full removal will always be more expensive than a qualified “recover” job.
  • Want to learn more about navigating the building code, energy code, and manufacturer guidelines? Check out our blog: What to Know About Roofing Code Requirements Before Replacing Your Commercial Roof 
• Insulation Requirements and Condition: Commercial roofs must meet minimum energy performance standards. Most areas require at least R-20 insulation, while some require R-30 depending on the building type and use. You might need to add insulation if your existing layers don’t meet code. But here’s the real catch—if that insulation is wet, it needs to be removed and replaced.
  • Wet insulation compromises energy performance, traps moisture, and can lead to long-term damage. Unfortunately, you can’t see wet insulation just by looking. That’s why we use non-destructive testing tools like: infrared scanners and nuclear moisture meters. These tools help us pinpoint problem areas without tearing up the entire roof.

• Roof Deck Condition: The last hidden—but critical—component is the roof deck itself. This is the structural layer beneath the insulation that supports the entire roofing system.
  • If there’s rot, rust, or other structural damage, those sections need to be replaced before any new materials are installed. Replacing the roof deck adds cost, but it’s also essential for safety and long-term performance.
  • Related blog: What Is a Roof Deck, and Why Does It Matter? 

So… What Does That Mean for Your Roofing Budget?

Taking all these factors into account, the cost of a new commercial roof can vary widely. Here’s a ballpark: 

• Simple recover over one existing layer, with minimal detail and no structural issues: $4-$6 per square foot 

• Full tear-off, with R-30 insulation, complex detailing, and roof deck repairs: $20–$30+ per square foot 

In other words, the price from one extreme to the other isn’t just double—it can be three or four times higher, depending on what we uncover during the assessment. 

If you’re trying to understand where your building fits on that spectrum, we’re here to help. At Weather Shield Roofing Systems™, we’re committed to transparency, education, and helping our clients make smart, cost-effective decisions for their roofs. Contact us today!