Roofing contractor inspecting a roof

What Happens During a Commercial Roof Inspection?

Perhaps you recently noticed brown spots on your ceiling, or you’ve witnessed water dripping from your roof.

Either way, it’s time to take action and get your problem fixed.

What should you do first?

Your first step is to call a couple commercial roofing contractors and get free inspections.

The reason you want to call a few contractors is to see what discoveries they find, what the prices are, what options they give you, etc. This will help you pick the best option for you and your building.

Most roofing contractors will perform free commercial roofing inspections, if they don’t, then choose someone else. Roofing contractors perform free inspections with the hopes they will get the job after their assessment.

It only makes sense that the contractor who performs the best inspection will probably get the job. The best inspections are produced by:

  • Proposing a solution that fixes your problem
  • Finding every opportunity water has to enter the building
  • Finding a solution that’s cost-effective
  • Explaining the deficiencies and solutions in an easy-to-understand manner
  • And much more

At West Roofing Systems, we’ve seen all kinds of roofing inspections, discoveries and recommendations given to building owners since 1979.

But what goes on during the actual inspection? Today we’ll go from start to finish on what you can expect to see happen during a commercial roof inspection.


What Happens During a Commercial Roofing Inspection?

A commercial roof inspection starts from the inside

A professional roofing contractor will begin a roof inspection from inside the building. The reason is to see where water is concluding its route. Where water ends its route is a great indication of where the leak began.

For example, if there are water stains in the bathroom, the location straight above the bathroom on your roof is a great estimate of where water is entering the building.

Another indication is a penetration near that area. For example, if directly above the bathroom on the roof is an HVAC unit, a great guess is that the leak starts near this area.

A commercial roof inspection includes walking the roof

A professional roofing contractor will walk the roof in search of unusual circumstances, such as:

  • Ponding water
  • Holes in the substrate
  • Cracks
  • Blisters
  • Uplifted seams
  • Uplifted nails and/or shingles
  • And much more

A roofer will start from the perimeter of the roof and work their way towards the middle of the roof. One reason is that you make sure you don’t forget an area of the roof. Another reason is that perimeter edges are areas that have a higher probability of causing a leak versus the field of the roof.

The reason is that perimeter edges are end points on a roofing system, which can be lifted by wind. This usually causes the edges to lose adhesion on a single-ply roofing system before the field of the roof does.

A commercial roof inspection includes taking a few core samples

What is a core sample? A core sample is the removal of a small portion of roof in order to determine facts about the field of the roof, including:

  • How many roofing layers there are?
  • What material is the substrate?
  • The level of saturation and/or moisture
  • How old the roof is?

Here’s an example of a core sample:

Roof Core Sample during an inspection


If there’s a drop ceiling or circumstance to where you cannot see the roof deck from the inside, a core sample will tell you what type of decking is present (wood, steel, concrete, etc.).

During a commercial roof inspection, the amount of core samples will vary depending on the size of roof, slope, where water travels, and highlighted areas during the internal inspection.

On average, a roofing contractor will take 1-2 core samples for every 10,000 sq. ft. of your roof. Of course, a roofing contractor will repair the area the core is taken from by using TPO or EPDM patches, or by using silicone inside the area, around the core and on top of the existing substrate.

A commercial roof inspection includes a report

After the visual inspection and core samples have been taken, a detailed report will be given to the building owner.

The report will include areas that are causing leaks, areas on the roof that are saturated, photos of these areas, and recommendations going forward.

These recommendations can include whether to repair, restore or replace your roof. Here are examples of when each of these could be recommended:

Repair – after your inspection, less than 5% of your roof is saturated and there’s only a few areas allowing water to enter the building. If the remainder of your roof is in good condition, the most cost-effective solution is to repair these areas.

Restore – after your inspection, less than 25% of your roof is saturated, but the remaining lifetime of your roof is less than 2-3 years. If a restoration is not performed, a complete tear off will most likely be the result at the end of that third year. A complete tear off is estimated to be 3-4x more expensive than a restoration.

Replace – after your inspection, more than 25% of your roof is saturated. It would be more cost-effective to replace the entire roof, as opposed to repairing a large portion of your roof, with more repair likely in the near future. This is similar to replacing an expensive car part (say a $1200 transmission) on a 20-year-old car that will likely need other repairs very soon.

How long does a commercial roof inspection take?

You may be wondering; “How long will a roofing contractor be on my property?” For an average 20,000 sq. ft. commercial building, it takes approximately 30 minutes to 1 hour to perform a roof inspection.

A roof inspection can take shorter or longer depending on:

  • How many penetrations are the roof (each one needs inspected thoroughly)
  • How many roof sections there are (every section is inspected differently)
  • How many different types of roofs there are

Once the roof inspection is complete, then you sit back and wait for the report to come to you.

How long until I receive my commercial roof inspection report?

A roof inspection report is usually sent to the building owner in 3-5 days.

What will be included in the inspection report?

Inspection reports will include:

  • the deficiencies within your current roof system w/photos and clear explanations
  • what options you have in repairing your roof
  • a quote for the work proposed

Once you collect a few quotes from other roofing contractors, then it’s time to compare them and make the best decision for your business.

Next steps after you receive a roof inspection?

Once you receive multiple roofing inspections and quotes, it’s time to review them.

Which company made the best recommendations?

Which company found the most deficiencies (that were actually deficiencies)?

And which company has the most cost-effective solution to fix my problem?

At West Roofing Systems, we’re happy to walk building owners through the entire process and go over the potential options with you, whether we decide to work together or not.

We’re just trying to help educate building owners as much as we can so they can make the best decision for their roof.

Need more insight?

Read More: Lies roofing contractors tell after you receive your roof inspection.

This post will tell you:

  • how roofing contractors lie about having their own in-house roofers
  • how they lie about price
  • how they lie about getting you to perform a more expensive solution
  • how they lie about what’s covered in the warranty

Enjoy! And thanks for reading!

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