Structural Inspections

Detect Structural Details

  • Roofing details
  • Wall details
  • Ceiling details
  • Floor details

Capabilities

Roofing Details

Depending on the construction, roofing details that may be viewable with an infrared camera include the placement of joist, insulation, fasteners, blocking, and others.

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Fastener patterns due to the minor amount of heat transmitted thru the fasteners.

Wall Details

Depending on the construction, wall details that may be viewable with an infrared camera include the placement of studs, insulation, fasteners, blocking, piping, reinforcement, and others.

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Locate or confirm the placement of reinforcing in masonry walls.

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Studs and bracing in wood frame construction.

Energy Loss Inspections

Opportunities to Improve Building Performance and Lower Cost

  • Missing insulation
  • Lack of insulation
  • Air leaks in or out

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This thermogram shows air leakage at the base of a wall.

 

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Image from a roof inspection showing heat loss through a open joint in a single layer of rigid board insulation.

 

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      Warmer windows are spandrel glass where the insulation has fell away behind them.

Moisture Inspections

Moisture Inspections

Opportunities to Improve Building Performance and Lower Cost

  • Roof inspections
  • Wall inspections

Roof Inspections

Quality assurance inspections

Performed during or shortly after the completion of a new roof or replacement roof project.  The purpose of the inspection is to show any of the hidden details that are viewable with the infrared. What is viewable depends on the type of roof, insulation and installation.  This type inspection should be planned in advance of the project.

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Fastener patterns due to the minor amount of heat transmitted thru the fasteners.

Preventative roof moisture surveys

A cost effective use of infrared in low-slope roofing.  Inspections are scheduled annual or biennial depending on the age of the roof and are started well before the expected decline of the roof system.  The first inspection serves as a baseline.  Minor problems are located and marked for repair, sometimes even before they leak into the structure.

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This small wet area was only 2 feet across, representing a minor inexpensive repair on this TPO roof system.

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This large wet area contained roughly 350 square feet, representing a major and expensive repair.

Inspections to pinpoint hard to locate leaks

Most leaks can be located and stopped without the use of an infrared camera.  There are some leaks though, that using infrared could be beneficial, even considering the cost. Those leaks are the ones that keep coming back, or maybe never leave.  The ones that several have looked at and it still leaks.

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Looking up at a steel deck, the cool (darkest) spot is where the leak first hit the decking. The rib that shows cooler than the decking is the one where the water is running

Pre-restoration/replacement roof moisture surveys

The most common type of roof moisture survey accomplished with an infrared camera.  The survey is performed before a roof is restored or replaced to determine how much, if any, of the insulation will need to be replaced.

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A clear distinction can be seen between the the wet insulation boards to the right and the dry to the left.

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Open flashing around this pipe was found to be the apparent cause of this wet area located on a MB roof system.


Wall Inspections

Locate moisture in EIFS

EIFS is everywhere and everywhere EIFS is moisture is also.  Most everything behind the surface is adversely affected by moisture.  It is important to stop moisture before it can damage the insulations or structure.  An inexpensive non-destructive infrared inspection once each year can help protect the investment of a entire building shell.

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Darker areas to the right contain moisture under the surface of the EIFS.

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Moisture appears to be penetrating along a crack in the surface.

Locate moisture in masonry

Masonry units that are sealed by paint may take on moisture through pinholes in the paint.  The moisture affects the surface temperature which is visible to the infrared camera.

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Moisture in this masonry wall shows as darker.

Trace leaks behind metal panel, vinyl and other thin sidings

Moisture on the back side of a thin panel will change the surface temperature and may be viewable by the thermographer.

Thermography Brief – Moisture in Metal Roof Systems

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Large cool (dark) area indicates moisture in the vinyl faced roof insulation. Green arrow points to apparent leak entry along rake edge of roof.  Red arrow points to single dripping location approximately 30’ down and 12’ over from entry point.

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Red arrow points to single dripping location from this large wet area. Cooler (darker) pattern indicates moisture in the insulation.

Additional Notes

  • This 20,000 square foot building had 10 wet areas totaling an estimated 1,255 square feet.
  • 7 of the areas were wetting the insulation but had not started to leak to the interior.
  • Best time to inspect and trace leaks to entry point is during or shortly after a rain.
  • Some insulations dry faster and patterns may disappear within a few hours after a rain.
  • Patterns often indicate the path and/or entry point of the leak.

Download PDF of Thermography Brief – Moisture in Metal Roofs

A Reminder to Cut the Roof

Stuart L. Raney Level III Certified Infrared Thermographer

It is a typical roof inspection using an infrared imager to locate hidden moisture. The roof is in pretty good shape and no exceptions have been located on the first two sections. Walking across the third roof section, the first exception is spotted. It is a small one, roughly 2’ x 2’, and appears to be half of a 2’ x 4’ Perlite board.

Stepping in the middle of the exception reveals the softness created when board type insulation becomes wet. With a small exception like this, it is tempting to mark it and move on to the next, but first let’s check it with our capacitance meter. Sure enough, the meter pegs the needle, but to make sure we whip out the pin-type moisture meter. Inserted into the center of the area, it also pegs the needle. So now we have a footstep and three advanced pieces of technology that all agree the roof is wet, or do they?

The footstep only tells us the roof was slightly softer in that area. The infrared imager only reports that the radiated energy was slightly higher. The capacitance meter only reports that the electrical impedance of the area is different from the area around it. The pin-type meter only reports that it encountered a different electrical resistance.

In order to confirm the presence of moisture we take a core sample of the roof. What we found was a piece of sheet metal laid below the membrane, apparently to cover the opening left by an old vent pipe that had been removed. The metal changed the radiated energy seen by the imager, the impedance seen by the capacitance meter, the resistance seen by the pin-type meter and small hole in the deck changed the firmness felt by the footstep. All these were good reasons to suspect a wet area but none good enough to verify one, even when all four agreed.

This is an old tip, but one worth revisiting. This exception was actually encountered on a recent inspection and could have been misinterpreted had the roof not been cored to confirm or deny the other results.

Perhaps a good way to understand the importance of core cuts is to realize that the visible evidence of a core is the only method of investigation that determines if a roof is wet or dry. Infrared imagers, nuclear gauges, capacitance meters and even pin-type resistance moisture meters can only be used to narrow down areas of the roof and limit the number of cores that must be taken. So if you are in the business of roof moisture surveys, your primary tool is a core cutter. You just use the fancy equipment to tell you where to do the real work.

First published as an irinfo.org Tip of the Week for August 31, 2009

Roof Inspections Don’t Cost (in the long run)

Roof inspections do not have to be major endeavor or investments. The most important inspection may be the walkover performed by the building owner, manager or the maintenance guy or gal. Okay, maybe a roof inspection cost a little for the maintenance person to walk around on the roof for a couple hours, but it doesn’t take much of a find for the inspection to pay for itself in real dollars. The modern commercial roof system will cost somewhere between a couple dollars per square foot to maybe ten to twenty times that depending on size, complexity and the materials used in the roof system. The walk-around finds one small hole in the roof that is leaking rain water into the system. The leak has not made it past the insulation layers and decking, so no one knows it is there until the inspection finds it. A call to the roofer and the hole is repaired for $200.

What if there is no inspection and no found hole? The leak may wet out a large area before it leaks into the building and prompts a call to the roofing contractor. We’ll be conservative and say it wets one 4’ x 8’ board of insulation, leaks into the building, phone call, roofer sends out two techs; they spend a 1/2 day, find the hole and repair it for $800. Further investigation determines the insulation is wet and should be removed because this location is over the something-critical area. Removal and replacement of the 4’ x 8’ area costs another $1,500 for a total of $2,300. The figures are imaginary, but the scenario is very real and happens every day.

Which is better? The maintenance person finding the small hole and the minor repair for $200+/- or waiting until the drip hits the floor and the major repair for $2,300+/-.

True Cost of Maintenance

The longer a given roof last the lower the lifecycle cost. Any given roof will last longer with maintenance. If not enough maintenance is performed, the lifecycle is decreased and lifecycle cost increases. If too much maintenance is performed, the maintenance cost exceeds the benefit of increased lifecycle and lifecycle cost increases.  There must be a balance between cost of the maintenance and benefit to the lifecycle.  Just the right amount of maintenance increases the lifecycle and reduces the lifecycle cost to its lowest possible number. The true cost of maintenance is therefore $0.00.