About (IR) Infrared Inspections

It's a known fact that many new roofs will be leaking at the end of their first year. Within five years even more will have problems stemming from poor installation, faulty design, failed materials and lack of annual maintenance and repairs.

While the leaks themselves may be the owner's largest headache, the water that is introduced into the roof system quickly causes other problems, usually more subtle than leaks but more destructive in the long-term.

Listed below are the worst offenders:

• When a wet roof system deteriorates prematurely: Blistering, ridging, delamination and accelerated rusting of the metal deck all contribute to roofs being replaced every eight years on the average, when they should be lasting 15-20 years.
• The water alone in a two-inch thick piece of saturated roof insulation can weigh up to 650 pounds per square, adding to the overloading of a roof's structural system.
• To "fix" leaky roofs, some owners are installing new single-ply membranes right over the old roof-wet insulation and all. They are now operating under a time bomb, which ticks away as the damage continues unnoticed.
• The insulation once wet, not only loses much of its insulating value, but becomes an excellent thermal conductor, resulting in wasted energy for both heating and cooling.
• Repairs, which all roofs will need at some point, cannot be made effectively when the wet insulation is left in place. Usually, these repairs fail and the leak begins again-if it was ever stopped in the first place.

Detecting wet insulation and other anomalies with an infrared camera is the key to a predictive maintenance program that will assist in keeping your customer's roofs leak free and in turn extending their respective service lives. 

New roofs should be surveyed upon acceptance from the contractor to document their baseline condition (and ensuring that you are getting what you pay for).  Roofs are also surveyed just prior to the expiration of any warranty or guarantee, this initial survey will help to establish the true condition of the roof. Any roof that is scheduled for replacement should be surveyed as well; many are, in fact, easily salvaged at tremendous savings.

A Thermal Imaging survey will quickly locate suspect areas where moisture is retained or trapped. Knowing the exact location of the trapped moisture will allow for an accurate decision to be made regarding the remedial repairs necessary. 

A Thermal Imaging Survey should be carried out:

• When leaks are suspected within the roofing system
• Prior to acceptance of a new roof system
• Before any existing warranties expire
• Before acquiring a new building
• Before roofing over an existing roof system
• For planned maintenance purposes
• When a pre-purchase construction report is needed

Contact Sitemark For:

• Infrared Inspections before Warranty expiration.
• Infrared Survey before a Real Estate Investment.
• Infrared Survey before a contractor begins work.
• Infrared Inspection after a completed project.
• Infrared Survey to investigate suspected water intrusion problems in residential buildings and commercial buildings.
• Infrared Inspection Surveys to prevent and predict equipment failure.
• Infrared Survey to locate areas of energy loss.
• Infrared Inspection to detect roof leaks.

There are four types of buildings by use:

• Residential-single family homes, apartments and dwellings of all types
• Commercial-office buildings, retail stores and shopping malls
• Industrial-manufacturing plants and facilities
• Institutional-colleges, universities, hospitals and government buildings

Building IR applications are divided into the following categories:

• Energy Audit Surveys
• Moisture Intrusion Surveys
• Insulation Q/C Surveys
• Structural Component Surveys
• Insect and Rodent Infiltration Surveys

Infrared thermography can be used as a building construction quality assurance tool. All building materials absorb, retain and radiate thermal energy at different rates; therefore building components can be checked for quality of installation using IR. In very cold climates, poorly installed insulation and moisture protection barriers can lead to condensation problems and the degradation of the building itself. In warm climates, as “fresh” moist outside air is mechanically introduced into buildings in an attempt to make the building cooler, condensation and its side effects - mold and mildew, become a real threat to building owners and managers, in reality and in the form of health-related lawsuits.

Improperly installed insulation and air seals in buildings can be detected, documented and measured using IR and blower door testing (coming soon). Building components “inside” the walls, ceilings and floors are recognizable using infrared because the surface temperatures are affected by their differences in mass. For example, infrared thermography can be used to determine the presence and correct placement of grouted cells in concrete block walls. If the owner of a new block building spends a little money checking the building construction with infrared thermography, the contractor will have little choice but to build the building to specifications, or face the added direct cost of correction and resulting loss of schedule repercussions.
Inspecting buildings for heat loss was one of the first commercial uses for infrared thermography. As we decide to become less dependent on fossil fuels, IR will again be used as it was in the 1980’s to monitor the energy efficiency of buildings, but now with more technologically advanced IR cameras and more thermographers, more and more buildings will become energy efficient and better-built.

The Basics of Infrared Thermography

Infrared Thermography basically identifies thermal anomalies located on the roof. These thermal anomalies are often associated with the roof substrate materials that have retained moisture. During elevated temperatures “wet” substrate materials will retain a greater amount of heat compared to adjacent “dry” materials.

After the heat source is removed (following sunset) and the surface of the roof begins to cool, the infrared camera can detect the differential “heated wet” substrate materials. The thermal camera shows the “wet” areas in a contrast color compared to the surrounding “dry” areas. At Sitemark we verify all infrared readings with a Tramex “Leak Seeker” (Photo A), an Electromagnetic Moisture Detection Instrument.  The instrument generates two low frequency electronic signals, transmitted through parallel electrodes incorporated in the rubber electrode mat, which is attached to the underside of the instrument. Placing the unit on the roof surface in areas suspected to contain subsurface moisture readily verifies or refutes the indication of the infrared camera image.  A Relative Scale from “0” (Dry) to “100” (Wet) provides an Analog reading of detected moisture.

Confirmation of suspected wet areas can also be obtained through the use of invasive probe method via Delmhorst Digital Moisture Meters should it be necessary.  The combined use of these tools ensures the utmost accuracy when surveying roofs, walls and other building systems.    

The “wet” areas are marked, numbered, and documented by capturing an image in the infrared camera and a control image with a digital camera. Typically, further verification of suspected “wet” areas is confirmed by taking a roof core sample to observe the condition, composition, and quantity of moisture. While the sample is open, readings are taken by a Delmhorst Moisture Meter.  This instrument works on the principle of DC resistance. When the electrode pins are inserted into the substrate (roof insulation), the electrical resistance between the electrodes is measured and indicated on the digital display.  If moisture is present in the insulation the electrical resistance between the pins changes (the higher the moisture content, the greater the reduction in resistance) and is reflected in the digital readout.  The instrument, which translates the resistance into percentage of dry weight moisture content, accurately measures the level of resistance. The instrument gives moisture readings from 0 (“Dry”) to 33 (“Wet”).

The Roofing Contractor is to coordinate with the Roof Consultant to verify the exact areas of “wet” or nonfunctional roof substrate to be removed prior to performing the roof improvements.

Performing the survey

A roof moisture survey involves three separate operations: the visual inspection, the infrared survey, and the follow-up work. Each operation is vital to the end result of returning the roof to a leak-free condition.

A visual inspection of the roof is performed before the infrared survey. The visual inspection details the nature and locations of any leaks, the repair history, and an inventory of the condition of the roof.

The infrared survey is typically conducted at night, beginning about 1-3 hours after sunset, depending upon the weather, roof system and conditions. With ideal conditions, patterns may remain visible until very late at night.

How much of the roof area can be surveyed in one evening? Depending on the complexity of the system and the number of problem areas, it is possible to cover at a minimum 40,000 square feet and as much as 150,000 square feet a night.

During the survey, the thermographers assistant outlines the areas of wet insulation directly on the roof as depicted by the thermal imaging equipment. Generally, the assistant also verifies each suspect area, using a capacitance meter. Verification of suspected “wet” areas is essential to the survey process. The primary and secondary confirmation ensures that correlations of thermal patterns with areas of moisture are indeed accurate.

The information from the survey is then passed out to the contractor, architect, engineer, consultant or building owner. This is the key to both formulating a maintenance strategy and making repairs that keep the roof leak-free.

Most roofs benefit from being resurveyed on a periodic basis in order to monitor the effectiveness of repairs and locate new or recurring problems.