Will a thermal scan work on this roof?

Stone ballast and pavers store the day's heat themselves and mask the small differences a scan reads, so a thermal scan does not suit this roof, and it is surveyed another way: a nuclear or capacitance survey takes readings on a grid across the roof. Which one suits depends on the membrane under the stone; capacitance, for one, is not used over black EPDM, which leaves the nuclear gauge and cores. Whatever either survey finds, cores confirm it.

Moisture survey methods compared

Gravel set into a built-up roof throws warm patterns that can be impossible to tell from small wet areas, so a thermal scan is a poor fit here, and the roof is usually surveyed another way: a capacitance or nuclear survey takes readings on a grid across the roof. Whatever either survey finds, cores confirm it.

Moisture survey methods compared

Reflections off the panels spoil a thermal reading, so a thermal scan is the wrong tool on a metal panel roof, and a capacitance scanner does not suit metal either. The survey for a metal restoration is a walk of every seam, lap, fastener row, curb and penetration, with the roof plan in hand, noting the panel type and where the rust is. A membrane section on the same building may still suit a scan; run the tool again for it. If anyone suspects wet insulation under the panels, only an opening or a core confirms it.

Restoring a metal roof

Closed-cell spray foam does not hold water the way board insulation does, so a thermal camera has little to find in it. A foam roof is surveyed on foot with the roof plan, marking worn and missing coating, sun-damaged foam, gouges, pecked holes, blisters and every penetration. An electrical-impedance (capacitance) survey is another method used on foam. Whatever any survey suggests, cores show whether water has got into the foam.

Restoring a spray foam roof

A thermal scan looks for wet insulation under a membrane, and exposed concrete has none on top. The deck is surveyed on foot: cracks across the slab, joints whose sealant has let go, spalls, failed sealant at penetrations and water standing in low areas, with an adhesion test patch to settle whether a coating holds. A deep spall or a crack that keeps moving goes to the building's engineer. Where the concrete sits under insulation and a membrane, answer for that roof instead; there, as on every roof, cores confirm what any survey finds.

Restoring a concrete roof deck

The camera looks for wet insulation, but lightweight insulating concrete and poured gypsum hold moisture of their own, from when they were poured and from service, which makes a thermal survey over them difficult to read. Cores say what the deck and the layers above it hold, and a walk-through finds the laps, flashings and penetrations worth checking first. Whether a capacitance or nuclear survey adds anything on that deck is for the contractor or a roof consultant to say. Whatever any survey finds, cores confirm it.

Moisture survey methods compared

A thermal scan finds wet insulation because wet insulation holds the day's heat. Expanded polystyrene does not hold water the way perlite, wood fiber or glass fiber board does, so the camera is the wrong tool for it. Cores say what is actually up there and whether it is wet, and a walk-through finds the laps, flashings and penetrations worth checking first. Ask whoever surveys the roof whether a capacitance or nuclear survey suits that build-up. Whatever any survey finds, cores confirm it.

How core samples confirm a survey

ASTM C1153, the standard practice for infrared roof moisture surveys, is written for roofs with insulation above the deck, against the membrane. With the membrane laid straight on the deck, there is no wet insulation for the camera to look for. A walk of the roof and cores where anything is suspect settle it; over a wood, concrete or gypsum deck an electrical-impedance (capacitance) survey is another option, though not over black EPDM. Whatever any survey finds, cores confirm it.

Moisture survey methods compared

Thermal readings are less dependable on reflective surfaces. A white surface reflects sunlight, so less of the day's heat goes into the roof for the camera to read after sunset; an aluminum coating adds reflections that spoil a thermal image. On a highly reflective or already white-coated roof a scan is the wrong tool. Tell us what is on the roof and how long it has been there, and we will say whether a flight is worth it or which survey fits instead. Either way, cores confirm what any survey finds.

Moisture survey methods compared

A single-ply, modified bitumen or smooth built-up membrane over insulation boards, with a dark surface that takes in the sun, is the roof the method was made for. It needs a sunny day followed by a clear, dry, calm evening; the drone flies once the sun has set. You get a map with any areas that look wet outlined and measured in square feet, video from the flight and a written assessment. Nothing has to be decided until you have seen the map. We arrange scans anywhere in the US and fly only with the owner's go-ahead. The scan marks suspects; the cores confirm them.

Request a moisture scan

The roof type and the surface suit a thermal scan. The camera looks for wet insulation boards, so the one thing left to know is what lies between the deck and the membrane: EPS foam board, lightweight concrete or poured gypsum would change the answer. Request the scan with what you know, including anything an old roof plan or a past core report says, and we will say whether to fly before anyone does. The scan marks suspects; the cores confirm them.

Request a moisture scan

Not knowing what is on the roof, or under it, is normal. Send the building's address with whatever you know: what the roof looks like, its age, what an old roof plan or the last roofer's paperwork says. We will say whether a thermal scan suits the roof, or which survey does, before anything is booked. We arrange drone moisture scans for commercial low-slope roofs anywhere in the US, and fly only with the owner's go-ahead. Whatever any survey finds, cores confirm it.

Request a moisture scan