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Sample moisture scan report

One real roof, scanned

A sample from a real drone moisture scan of a commercial roof of about 50,000 sq ft, with the address, the people and the companies removed and the map re-oriented: 28 areas flagged, 1,929 sq ft in all, 3.8% of the roof. It shows the map and the daylight and thermal image pairs; a full scan also comes with video from the flight and a written assessment.

Request a moisture scan How the scan works
Thermal image from the sample scan: a warm band along a strip of roof beside two rooftop curbs, inside a white dotted outline

What came back

The scan in numbers

Read the total first: 1,929 sq ft, 3.8% of the roof, is what may have to come out and go back once cores confirm it. There is no single standard for how much wet is too much; manufacturers commonly draw the line somewhere between 15% and 30% of the roof.

Roof A commercial roof of about 50,000 sq ft
Areas flagged 28
Flagged in total 1,929 sq ft, 3.8% of the roof
Size of each area From 2 sq ft to about 206 sq ft
Warmest area 14.5 °F above the dry roof around it (pair A below)
Faintest areas Nine of the 28 read less than 5 °F above the dry roof around them
When it was flown A clear evening, about an hour after sunset
Cores taken None in this sample

Run the numbers

Suspected until cored. Nothing in this sample was cored, so every outline is a suspect, and the 1,929 sq ft is the area to check, not the area to replace. The scan marks suspects; the cores confirm them.

Section of the sample roof's thermal map: two roof sections meet along a straight line, the upper one brighter, with white dotted outlines strung along the line and across the lower section

The whole-roof map

Reading the map

Brighter is warmer. Wet insulation holds the day's heat longer than dry insulation, so after sunset the membrane over it stays warmer than the roof around it. The white dotted outlines are the areas the scan flagged, each measured in square feet. On this roof they gather along the wall line where two sections meet, beside curbs and rooftop units, and around a ponding stain. Color alone proves nothing: unit exhaust, standing water, dirt and thicker membrane can each read warm over dry insulation. Every outline is a place to core, not a finding.

How infrared surveys work, and when they do not

Six of the 28 areas

Slide from daylight to thermal

From the same sample, with the address, the people and the companies removed. Each pair is one patch of roof, lined up to match: slide across to wipe between the daylight photo and the thermal image. The dotted outline, orange on daylight and white on thermal, is the area flagged.

  • Pair A: a strip beside two rooftop curbs

    Pair A in daylight: a long, pale strip of membrane beside two square rooftop curbs, streaked with dark stains, inside an orange dotted outline Daylight
    Pair A in thermal: the same strip shows as one bright warm band inside a white dotted outline, with cooler roof on either side Thermal
    Area flagged
    204.7 sq ft
    Warmer by
    14.5 °F
    Peak
    91.4 °F
    The warmest area on the roof, a strip along the wall where two roof sections meet. Stains by day and a hot band after sunset in the same strip: two separate clues agreeing, which puts it first in line for a core.

  • Pair B: between rooftop units

    Pair B in daylight: an irregular orange dotted outline wandering across gray membrane between a square curb, a pipe and other rooftop equipment Daylight
    Pair B in thermal: a large, irregular warm shape inside a white dotted outline, running across the roof between the units Thermal
    Area flagged
    140.9 sq ft
    Warmer by
    12.9 °F
    Peak
    88.8 °F
    Second only to pair A among the six, at 12.9 °F above the dry roof around it, with the ragged, spreading edge that water moving through insulation tends to leave. Next in line for a core.

  • Pair C: nothing to see in daylight

    Pair C in daylight: ordinary gray membrane sheets and laps with nothing unusual on the surface, an orange dotted outline drawn over them Daylight
    Pair C in thermal: a clear warm patch filling a white dotted outline on otherwise cooler roof Thermal
    Area flagged
    34.2 sq ft
    Warmer by
    9.5 °F
    Peak
    88.1 °F
    The membrane looks like the roof around it. Nothing on the surface would lead anyone to cut here: the case for the camera.

  • Pair D: beside an air-handling unit

    Pair D in daylight: gray membrane beside a rooftop unit with a fan, an orange dotted outline starting at the unit's corner and spreading across the roof below it Daylight
    Pair D in thermal: a warm shape inside a white dotted outline reaching out from the corner of the rooftop unit, which itself reads cool Thermal
    Area flagged
    92.0 sq ft
    Warmer by
    8.7 °F
    Peak
    87.2 °F
    The unit itself reads cool; the warm shape starts at its corner and spreads across the roof. The camera cannot see under the unit, so the outline stops at its edge whether or not the warmth does.

  • Pair E: under a temporary plastic cover

    Pair E in daylight: a sheet of clear plastic laid across a strip of roof beside two square curbs, an orange dotted outline under and around it Daylight
    Pair E in thermal: an irregular warm shape inside a white dotted outline along the covered strip Thermal
    Area flagged
    112.7 sq ft
    Warmer by
    10.5 °F
    Peak
    86.5 °F
    Someone had already laid a cover over a problem here. The flagged area lies under and around it, in a shape of its own: a repair sized to the plastic is sized to a guess.

  • Pair F: a ring around a ponding stain

    Pair F in daylight: a dark ponding stain on gray membrane between two rooftop curbs, an orange dotted outline wrapped around it in a C shape Daylight
    Pair F in thermal: a C-shaped warm band inside a white dotted outline, around a stain that reads no warmer than the open roof Thermal
    Area flagged
    176.2 sq ft
    Warmer by
    8.5 °F
    Peak
    84.5 °F
    The stain itself reads no warmer than the open roof; the ring of roof around it is what was flagged. A stain is a clue to check, not the outline.

Area flagged is estimated from the air; the cut line is set on the roof. Peak is the warmest surface reading inside the outline. Warmer by is measured against the dry roof right around each area, not one figure for the whole roof.

Reading the pairs

What the six pairs teach

Read any scan report in the same order: what the pictures agree on, what only the camera can see, and what a core will have to settle.

  • Agreement ranks an area; it does not confirm it

    Two clues in one place, as at pair A, put an area first in the coring order. It is still a suspect: a stain shows where water stood on the surface, not what is in the insulation.

  • What shows by day is a poor guide to the extent

    Pair C shows nothing by day. At pairs E and F the outline takes its own shape, not the shape of the cover or the stain: only the camera shows where the warmth runs.

  • Small and faint is not the same as dry

    Nine of the 28 read less than 5 °F above the dry roof around them. Wind blunts a thermal pattern, so faint areas are cored after the strong ones, and at least one still is.

  • Warmer than the roof around it, not the roof

    Pair D peaked higher than pair E, yet E read 10.5 °F above its surroundings against 8.7 °F. Against one roof-wide figure the two would rank the other way round.

How to read a thermal roof scan

Next steps

After the map: cores, cut-outs, coating

The map says where to look, not what to do. A roofing contractor takes it from here: we work with a network of installers, roofing contractors who apply these systems, and can introduce you to one anywhere in the US, who looks at the roof and says whether it is a good candidate for restoration.

  1. Core strong, faint and dry areas

    A core is a small cut through the roof that shows the layers, the insulation and whether it is wet. Start with the warmest and largest areas, add a faint one, and cut one where the map shows nothing, for comparison. Each core is patched the day it is cut.

  2. Mark the cut-outs on the roof plan

    Areas the cores confirm go onto the roof plan, with cut lines set on the roof back to sound material, not traced from the air. Sherwin-Williams Uniflex's own guide specification asks for a roof plan of the wet areas before coating. The total is the square footage coming out and going back.

  3. Replace what is wet, to matching thickness

    Wet insulation and the membrane over it are cut back to sound material, the insulation is replaced to matching thickness, and the patch is tied back into the field. A coating over a wet area would seal the water in.

  4. Restore the rest, by roof type

    If the cores and the installer say the roof is a candidate, an adhesion test patch settles whether it holds. Then the build-up for its type: an acrylic base and finish coat, or Silicone44 with no base coat. Applied over a sound, dry roof, a restoration system adds 10 to 15 years of service life.

  5. File the map and the core log

    A white coating makes later thermal work harder, so the map and the core log are the record of what was under the membrane before the coating went on. Keep them with the cut-out plan and the data sheets for whoever works on the roof next.

From scan to finished roof

Questions

About this sample

Is this a real roof?
Yes. It is a sample from a real scan of a commercial roof of about 50,000 sq ft, with the address, the people and the companies removed and the map re-oriented. The areas and temperatures shown for each pair are the scan's own figures; the roof's size is rounded.
What do the dotted outlines mark, and how exact are they?
The edge of each area the scan flagged as warmer than the dry roof beside it. The dots mark the edge without hiding the roof under it: orange on the daylight photo, white on the thermal image. Where an edge runs is a reading of the thermal image, not a measurement of wet insulation. The cores check the reading, and the cut line is set on the roof, back to sound material.
What do the temperatures mean?
They are temperatures of the roof surface, read from the thermal images on the evening of the flight. Peak is the warmest reading inside an outline. Warmer by is how far that reading sat above the dry roof right around the area. Neither is a moisture reading: wet insulation keeps the surface above it warmer after sunset, and other things can too. The whole roof cools through the evening, so the figures compare areas within one flight, not one roof with another.
Does a small difference mean the roof is dry there?
No. It means the signal was faint that evening. Nine of the 28 areas here read less than 5 °F above the dry roof around them, and faint areas are still cored, after the strong ones. The same goes for roof with no outline: nothing showed that evening, which is not proof that the insulation under it is dry.
What else is in a full scan?
This page shows a section of the map and six of the 28 areas as daylight and thermal pairs. A full scan comes with three things. The map: the whole roof, every flagged area outlined and measured in square feet, with a daylight photo beside each thermal close-up and how much warmer each read than the dry roof around it. Video from the flight. And a written assessment of what the scan found: a screening read, not a diagnosis, which the cores then confirm. Nothing about the roof has to be decided until you have seen them.
What did this roof's owner do next?
The sample covers the scan only, not anything the building owner decided afterwards. Nothing in it was cored, so it cannot say whether any of the 28 areas is wet.
Can a contractor ask for a scan of a client's roof?
Yes. A contractor, a facility manager or a property manager can ask on the owner's behalf. We fly only with the building owner's written go-ahead, and the map, the video and the written assessment go to the owner, to share with whoever prices the work. For the materials for the job itself, use the quote form.
Would a scan work on my roof?
It suits commercial low-slope roofs with insulation under a membrane: single-ply, modified bitumen and smooth built-up. It is the wrong tool for ballasted or heavy-gravel roofs, metal panel roofs, highly reflective or already white-coated surfaces, and insulation that does not hold water, such as closed-cell foam; those roofs are surveyed another way. We arrange scans for commercial low-slope roofs anywhere in the US.

Check whether a scan suits your roof

Before you budget

Get the same kind of map for your roof

Send the building's address with the request. You get the map, video from the flight and a written assessment, and nothing has to be decided until you have seen them. We quote the scan for your roof; it depends on the roof's size and where the building is.

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