How Does an Infrared Inspection Work on a Commercial Roof?
So, you’re doing casual research on spray foam roofing and you hear that you must replace the saturated areas of your current roof.
You think, how can a roofing contractor see what’s under the top layer of my roofing system?
Do they have some sort of magical power? Secret weapon? Do they totally guess?
Enter an infrared camera.
Or for more difficult roofs to detect saturation, a nuclear scanner (we’ll get into this later).
Since West Roofing Systems refuses to install any roofing system over wet and saturated areas (for many reasons), and has been doing so for more than 40 years, we know how important it is to be precise when identifying wet areas.
Today we’ll talk about why identifying saturated areas is important, and how we use an infrared camera as part of the entire inspection process.
What is an Infrared Inspection?
An infrared inspection, sometimes called thermal imaging, is the process of using a handheld Infrared (I.R.) device, or a nuclear scanner, in order to detect heat underneath a roofing membrane.
When the sun goes down and the top layer of your roof begins to cool, water that has surpassed your top layer and has settled into your insulation will still be warm from the days’ sun.
Since the saturated areas are still warm, they will appear on an I.R. device as a reddish color, where the cooler areas will be purple-ish.
A roofing contractor will use highlighter paint to mark the areas where there’s saturation so the roofers can remove these areas the following day.
Why include an infrared inspection as part of the roofing process?
An infrared inspection is beneficial to the building owner because you never want to install a roofing system over saturated areas.
What’s the dangers of installing a roofing system over a saturated area?
When water is trapped under a roofing system, it has two ways to go, up or down.
If it’s hot and the water is evaporating, it can rise and interfere with your new roofing system.
For a spray foam roof, blisters can form. Blisters can affect the way water travels on your roof, which can cause damage if water is ponding and not heading towards a drain.
For a rubber roof, when the water tries to evaporate, it can separate the seams, which creates an opportunity for new water to enter your roofing system.
Most likely, water will travel down into the deeper layers of your roof.
This water will affect your underlying boards and decking. With these areas saturated, it can eventually rot out your deck, which is a very expensive repair.
Also, this water can surpass the deck and find an opening into your building.
NOTE: Imagine getting a whole new commercial roof installed, one that costs thousands of dollars, and the next month, water is dripping from your ceiling. That’s why removing saturated areas isn’t just a consideration, it’s GREATLY recommended.
What happens after a roofing contractor identifies saturated areas?
After a roofing contractor identifies saturated areas, pictures are taken, and they are included in a roofing quote.
In the quote, an approximate determination of how much of the roof will need removed will be included.
NOTE: Sometimes there will be a caveat that says every extra square foot of removal/replacement will be $XXX cost per sq. ft. This happens because sometimes upon tearing off the saturated areas of your roof, the roofers will need to remove an extra few feet to get to a “bone dry” substrate.
This doesn’t increase/decrease the cost of the roofing project much, but it’s always nice to not have any surprises when the invoice comes.
There are light and dark colors on the IR scanner: which one is wet, and which is not?
It depends on how you set your cameras up.
Sometimes a roofing contractor will get onto the roof 30 minutes before an infrared inspection to identify where the low areas of the roof are located at. These are areas where water has been sitting a long time. It’s going to constitute that these areas are probably wet.
Usually wet areas show up bright red (to symbolize heat), and then slowly in different colors beyond that. This shows the severity of how much wet there is. It’s similar to a weather radar with rain. But it all depends on what style camera your contractor has.
When a roofing contractor highlights wet areas, do they go a certain distance outside of what the infrared says?
A roofing contractor will keep it confined to that area. When the roofers begin to tear off at these areas, they can see where the wet is and where it’s not.
Sometimes the camera didn’t pick up all the saturation, and removal will need to extend slightly outside the highlighted areas.
The roofers perform tear off until they reach a dry area. Usually it’s a few inches out until they can identify “bone dry” insulation.
Which areas of a commercial roof are usually saturated?
Areas that are usually wet include:
- Around HVAC units
- Areas where flashings are located at
Flashings can sometimes be deteriorating or pulling apart. If that’s identified, saturation is likely to be found.
Drains are a high probability for saturation because that’s where all the water goes. The flashings around the drain can also be deteriorating.
What happens if more than 25% of the roof is saturated?
If more than 25% of your roof is saturated, you’re better off completely tearing off your roof and insulation and getting a new roofing system.
If a large percentage of your roof is saturated and it’s allowing water to enter, it’s likely the rest of roof is in a similar condition, so in the long run, it’s cost-effective to replace the entire roof now.
Another scenario that happens is the roof may have less than 25% saturation, but the saturated areas are scattered throughout the roof.
A little wet here, a little wet there…
To remove multiple areas and fit the roofing system back together as one unit, your roof would look like a Frankenstein jigsaw puzzle.
In this case, due to excessive labor and the difficulty of fitting multiple areas back together, it’s cost-effective to get the entire roof removed and replaced.
Of the roofs that are infrared inspected, how many roofs are more than 25% saturated?
West Roofing Systems has been doing infrared inspections for more than 40 years on over 100 roofs each year.
In our experience, around 25% of roofs have more than 25% saturation.
This means that 25% of the commercial roofs we’ve seen need to be completely torn off, but 75% of them can be restored, avoiding the costly tear off.
Does a roofing contractor always have to perform an infrared inspection?
Before an infrared inspection takes place, a roofing contractor will take core samples.
A core sample is a sampling of your roof, usually a 1 in. square that’s a few inches into your roofing system.
The core will determine if there’s saturation, how many layers your roof has, and approximately how old your roof is.
On a 10,000 sq. ft. roof, a roofing contractor would pull at least 4 cores. If 2/4 are wet, then we’ll do the infrared to verify how much wet is on the roof.
If there’s 1/4 wet, then you know there’s probably only wetness in one area and that can be removed and replaced, leaving the rest of the roof untouched.
If all 4 core samples show indications of saturation, no infrared is needed. The entire roof will need to be replaced.
Some customers want the infrared done no matter what before a roofing project so they know (to great accuracy) what the total cost for the job will be. Totally understandable.
Some will just want a price per sq. ft. of removal/replace after the project is complete and find out later what the cost will be.
Every building owner is different.
How much does an infrared survey cost?
If the roofing project is under contract, most roofing contractors don’t charge for an infrared inspection.
If the project isn’t under contract, there is a small fee to perform the infrared survey.
What roofing systems can an infrared survey work on?
Infrared’s work great on spray polyurethane foam roofs.
They work great on rubber roofs. The trick on rubber roofs is that you need to hit the correct time of day when the sun’s heat has cooled down the top layer of the roof, which is usually 30 minutes after the sun sets.
Infrared’s don’t work great on Gravel Built-Up roofs. They just don’t display accurate readings. For BUR’s, a roofing contractor will use a nuclear scanner, which is another form of an infrared scanner, it’s just the size of a lawn mower.
On TPO roofs it’s borderline because TPO absorbs a lot of heat. So, the whole surface is the same temperature for quite a long time. Nuclear scans are the preferred method for TPO roofs.
Finishing touches on infrared inspections on commercial roofing systems
Hopefully today, you learned why an infrared inspection is crucial to the overall commercial roofing process.
If you’re considering getting a new roof, or getting one restored, it’s important to look at the work being performed…and the justifications why.
A scenario that happens quite often is one contractor will quote a job and say they are spraying foam, or putting down coating over the entire roof, with no tear off needed.
Another will recommend doing an infrared survey and identifying the saturated areas first, then determine the best course of action.
So just be aware of what’s out there.
If there’s anything you should take away today, it’s this…don’t ever apply a roofing system over saturated areas! It will cause you headaches right after your roofing project is complete…and many other times down the road.
Interested in starting a conversation about your roofing problems? We want to hear what you have to say. Please fill out the form on our “Request a Quote” page and we’ll call you ASAP to get some insight on what’s going on with your roof.
Author: Greg Palya
Greg Palya is the Digital Content Manager of West Roofing Systems, Inc. He has a B.S. in Marketing from the University of Akron and an MBA in Marketing from Walsh University. When he’s not trying to teach others about spray foam roofing and silicone roof coatings, you can find him on the basketball court or golf course.