Attachment_2_-_SOW_Appendix_A_YAO_-_Roof_Leak_Inspection_Report.pdf

US Bureau of Reclamation Yuma Area Offices

Roof Leak Inspection Report

Site Visit: November 11th , 2024

Report date: Revised December 22, 2025

Contents

Building 1 – YAO Admin Office

Building 2 – The Desalting Building

Building 3 – The YDP Admin Office

Building 4 – The Switchyard Control

NDT Science Fundamentals

Limitations of Findings

Attachments A, B, C, D, & E

Building 1 – YAO Admin Office

Background: Building 1. Original roof construction consisted of a built-up roof, the exact assembly as the roof currently on the Desalting Building (Building 2). The entire roof section has been replaced with an Elevate, formerly Firestone Building Products, white single-ply TPO (thermoplastic olefin) adhered membrane system circa 2010-2011, installed over a 22-gauge steel deck. Approximately 33,000 SF of roof.

Observations November 2024:

TPO roofing field. Appears to be in good to fair condition. With the exception of a satellite that has punctured the South elevation, there are no other apparent issues with the existing membrane. Roughly 50% of roof seams were probed and there was no indication of failure at roof seams.

TPO roofing penetrations. All issues seem to occur from improper maintenance of sealants at roof penetrations, as well as some capacitive indications of latent moisture at existing roof drains.

From the Elevate Roofing System Owner’s Manual, page 9:

“All metalwork, including counter-flashings, drains, skylights, equipment curbs and supports, and any other rooftop accessories functioning in conjunction with the Elevate roofing system, should be properly maintained.

Particular attention should be paid to sealants at joints in metalwork and flashings. If cracking or shrinkage is observed, the sealant should be removed and replaced with new sealant. In addition, roof sealants such as

Elevate Pourable Sealers and General-Purpose Sealant are considered maintenance items that are not covered under your Elevate warranty and must be maintained by the building owner. “

Expansion Joints. The roof expansion joints do not comply with National Roofing Contractors Association (NRCA) guidelines of being a minimum of 8” above expected water line. The top of the expansion joint curb is covered with EPDM material and secured with a termination bar that is barely 3” above the horizontal roof surface.

Every joint in the EPDM expansion joints appear to have adhesive failure and holes are present throughout the entirety of the expansion joint areas.

Thermal/Capacitance observations. ASTM C1153 procedures were followed to observe roof insulation for latent moisture. No thermal anomalies were observed. Non-destructive testing (NDT) utilizing impedance scanners was performed in accordance with ASTM D7954. NDT scanning observed trace amounts of latent moisture at roof drains, within a 5’ radius.

Interior damage. The interior damage is isolated to ceiling tiles only. No structural damage or damage to walls was observed. The active leaks at the HVAC unit would have typically a condensation issue from a blocked condensation line, pump gone bad, or something of that nature. The indication of roof leaks can be observed on the 2nd floor of the Yuma Area Office building ceiling with mineral fiber suspended tiles exhibiting stains or removed due to regular leaks. It is to be noted that some of the discolored tiles observed over office spaces where air handlers are located, are due to HVAC condensation leaks and are not from roof leaks; whereas the tiles below areas of the roof that are believed to be leaking are from the roof leaks.

Please reference Attachment B for TPO guidance

Alexander Silva Rectangle

Roofing overall

No unusual temperature differences observed through infrared scan.

TPO roofing overall

Sealant is degraded and in need of replacement

Line

Sealant degraded and in need of replacement at Vent Trough Roof VTR

Sealant in need of replacement at HVAC metal hood

Alexander Silva Line

Alexander Silva Line

Sealant in need of replacement at HVAC metal hood

Satellite roof puncture

Alexander Silva Line

Impedance testing at roof drain indicating trace amounts of latent moisture

Debris accumulation on roof

Sealant at structural framing leg in need of replacement

Puncture in EPDM expansion joint

Alexander Silva Line

EPDM membrane splice with adhesive faulure

Deterioration of TPO walkway

Alexander Silva Line

Building 2 – Desalting Building

Background:

Building 2. Built-Up Roofing (BUR with gravel 30+ years in age over 22-gauge steel decking. Approximately

103,800 SF of roof.

Observations November 2024:

BUR Roofing Field. Existing roof appears to have little to no maintenance in its tenure. Course aggregate shows areas of wind scour with exposed BUR missing in multiple places and exposed insulation and roof decking. These areas with wind scour have no weather protection and allow rain to penetrate the roof assembly with no restriction.

Skylights. 121 skylight curbs (12’ x 3.5’) each with (2) 6’ x 3.5’ acrylic double dome curb mount skylights attached with an aluminum mullion are present attached to wood curbs. All skylight curbs were flashed originally with a granulated modified bitumen roof flashing. Most skylight curb flashings have weathered away to expose wood curb with little to no weather protection. Skylights do not appear to be OSHA compliant for fall protection.

Expansion Joints. The roof expansion joints do not comply with National Roofing Contractors Association

(NRCA) guidelines of being a minimum of 8” above expected water line. The top of the expansion joint curb is covered with EPDM material and secured with a termination bar that is barely 3” above the horizontal roof surface. Every joint in the EPDM expansion joints appear to have adhesive failure and holes are present throughout the entirety of the expansion joint areas. All expansion joint curbs were flashed originally with a granulated modified bitumen roof flashing. Most expansion joint curb flashings have weathered away to expose wood curb with little to no weather protection.

It is recommended to remove all existing stone ballast, BUR roofing, and insulation and replace with new insulation and 80 mil TPO single-ply roofing with a 30-year warranty. ASHRAE 90.1 recommends a minimum R-value of R-5 c.i. on semi heated buildings in zone 2 – this will significantly reduce cost for replacement of roofing insulation.

***The government requested for repair recommendations and budget costs associated with repair recommendations. While the cost to make repairs may seem less than an entire roof replacement cost, there is no way to ensure the watertightness of the field BUR membrane under the thick layer of rock ballast. The whole roof has surpassed its useful life by 15+ years. By electing to make repairs noted in recommendations tab below, be assured that the roof will still leak in various places. The only way to ensure this roof will not leak is to replace the entire roof field membrane, all flashings, expansion joints, sheet metal flashings, and insulation. This roof is far beyond any repairs to extend its useful life.***

Thermal/Capacitance observations. ASTM C1153 procedures were followed to observe roof insulation for latent moisture. No thermal anomalies were observed. Non-destructive testing (NDT) utilizing impedance scanners was performed in accordance with ASTM D7954. No unusual impedance measurements found.

Please reference Attachment C for BUR guidance

Alexander Silva Rectangle

Roofing overall

EPDM expansion joint with tear

EPDM expansion joint with deteriorated mod bit flashing

Alexander Silva Line

Exposed insulation and deck as indicated on Attachment “A”

Alexander Silva Line

Alexander Silva Line

Exposed insulation and deck as indicated on Attachment “A”

Alexander Silva Line

Skylight mod bit flashing with extensive degradation

Alexander Silva Line

Impedance scan of BUR roof – No indication of latent moisture

Debris accumulation

Alexander Silva Line

Exposed insulation and wood curb at skylights

Alexander Silva Line

Alexander Silva Line

Extensive damage to expansion joints

Alexander Silva Line

Thermal scan was inclusive due to rock ballast. Findings were verified with impedance scanners and visual observations.

Building 3 – YDP Admin Office

Acrylic roof coating installed between 2016 and 2017 over a single-ply roof and polyisocyanurate insulation.

Approximately 3,000 SF of roof. A typical acrylic coating can expect to last approximately 10 years. This roof can be re-coated in perpetuity, as long as the insulation below does not become wet.

Observations November 2024:

Roof Field. Acrylic coating appears to be in fair condition. There appears to be some cracking at the corner flashings on the RTU curbs. Detail flashings on roof penetrations need to be reapplied with fabric and flashing grade sealant. The exhaust vent is not the correct vent for a low slope roof and is in need of replacement – it will allow water to enter without restriction.

Please reference Attachment D for acrylic coating guidance

Thermal/Capacitance observations. ASTM C1153 procedures were followed to observe roof insulation for latent moisture. No thermal anomalies were observed. Non-destructive testing (NDT) utilizing impedance scanners was performed in accordance with ASTM D7954. No unusual impedance measurements found.

Roofing field overall with baseline induction meter

Wrong exhaust vent installed.

Penetration in need of flashing grade sealant

Alexander Silva Line

HVAC curb flashings

Building 4 – Switchyard Control

Roofing consists of a closed-cell spray foam (SPF spray polyurethane foam) with acrylic coating.

Approximately 1,800 SF of roof.

Roof appears to be in overall good condition. One 2’ x 2’ area noted on North side with a small puncture with hidden moisture indicated on thermogram.

Please reference Attachment D for acrylic coating & SPF guidance

Thermal/Capacitance observations. ASTM C1153 procedures were followed to observe roof insulation for latent moisture. One small area of temperature difference observed, as noted. Non-destructive testing (NDT) utilizing impedance scanners was performed in accordance with ASTM D7954. One small area with unusual impedance measurements found that correlates with thermal camera findings.

Cut in SPF Roof at roof drain

Area of hidden moisture indicated on North Elevation above

Non-Destructive Testing Fundamentals

Infrared Science:

Infrared cameras detect infrared radiation (heat energy) emitted by objects and translate them to a specific color palette to highlight differences in energy. The darker areas are those that radiate less thermal radiation, which means that those areas are generally cooler. Brighter equates to the opposite, more radiation, and a potentially warmer target.

The goals of this observation were to detect any anomalies that may indicate heat loss/gain through the building envelope. Heat transfer can occur at wall penetrations, window to wall transitions, walls with inadequate insulation, or through windows themselves. As stated previously, the indication of a significant temperature differential can be observed by varying hues of color on the radiometric image.

According to ASTM, an infrared inspection requires a sufficient difference in temperature from inside to outside (∆T) for a sufficiently long period of time to produce discernible differences between areas with studs and areas that may contain insulation. The preferred measurement of ∆T is surface to surface because this minimizes problems with accounting for solar and wind effects. Air-to-air measurements are also permitted under this practice.

ASTM C1060 states that the interpretation of the thermogram allows determination of the following information:

Locations of the regions where insulation is apparently missing or defective and their total area.

Locations of the regions where the insulation is apparently intact and their total area.

Location and total area of added insulation.

Estimated total area of surfaces that cannot be inspected.

Interpretation of thermographic images requires awareness of the following types of patterns (anomalies):

Intact Insulation—As seen from the warm side of the construction: dark parallel lines, representing the framing; uniformly lighter areas between the framing lines, representing the insulation. As seen from the cool side of the construction: the framing lines are light. The areas containing insulation are uniformly dark. (Metal framing conducts heat better than both air and insulation. If insulation is present, the thermal contrast between metal framing and the spaces between may be very strong. Independent verification may be needed for metal-framed buildings to establish typical patterns for insulated and uninsulated areas.)

Insulation Missing Completely—As seen from the warm side of the construction: light parallel lines, representing the framing; darker areas between the framing lines, representing the empty space between framing members. Convection will be visible in vertical framing, as evidenced by a gradient from dark (cooler) at the bottom of the space to light (warmer) at the top. As seen from the cool side of the construction: the framing lines are dark, the areas between framing are light and convection is still lighter at the top of vertical spaces. (Metal framing with no insulation may not fit this description, except that missing insulation shows as a well-defined dark region, as seen from the warm side and as a light region as seen from the cool side.)

Other Thermal Patterns—Irregular variation of the thermal pattern in the spaces between framing members indicate a combination of possible causes, including varying density of insulation, convection or air leakage, moisture, or thermal bridges.

A partial list of examples follows: Variable density insulation often allows air leakage and convection and thereby creates intruding areas of surface temperature variation.

Areas where insulation contains significant moisture conduct heat much more readily than dry insulation or no insulation. Within the moist region, mottled and diffused thermal pattern are commonly observed.

Temperature variations within the pattern are not extreme. Conditions also allow for moisture to evaporate, on either the interior or exterior wall or in the interstitial space; this causes cooling of these surfaces below ambient air temperatures. Further, when the envelope is in thermal transition, moist areas, with their higher thermal capacitance, temperature is capable of changing more slowly (in either direction) than similar dry materials. Because of these three variables (conduction, evaporation, and capacitance), thermals signatures related to moisture are confusing and difficult to interpret.

Framing members and the presence of fasteners will cause thermal bridges.

Air leakage, usually at joints and junctions in the building envelope, typically produces irregular shapes with uneven boundaries and large temperature variations. Air leakage can be detected thermographically when air of a different temperature than the surface viewed comes from the side of the envelope opposite the observer. Air leakage also occurs on interior partitions as well as floors and ceilings that are connected to the envelope.

ASTM C1153 notes that the water retained in roofing systems decreases the thermal resistance and increases the heat storage capacity of such systems. This leads to thermal anomalies on the surface that are located using an infrared imaging system. These thermal anomalies depend upon the type of roofing system, the amount of moisture in the insulation, and the weather conditions. For a given roof, there are four weather related parameters that can cause significant changes in surface temperatures over wetted roof areas compared to dry areas.

These are: inside to outside temperature difference, the rate of change of temperature in the hours prior to viewing, the amount of insolation (sunlight), and the wind speed.

Acceptable weather conditions for a nighttime infrared imaging inspection will be light winds with some combination of a large inside to outside temperature difference, a rapid decrease in temperature in the late afternoon and a sunny day before scanning. Typically, an infrared inspection during cold weather relies on a large inside to outside temperature difference and an infrared inspection during warm weather is best during a cool night after a hot sunny day.

The wetting rates of roof insulations vary according to the type of insulation and the environmental exposure.

Allow new roofs with insulations that wet slowly, such as cellular plastics or cellular glass to dry at least eight months prior to conducting a survey.

Infrared thermography is used to assist with locating wet roof insulation but will not always identify the source of the moisture.

Using an infrared camera over gravel built-up roofs is challenging due to the following reasons:

1. Gravel Obstruction: The layer of gravel on the surface scatters and blocks the infrared radiation emitted from the roof substrate, making it difficult to detect temperature variations accurately.

2. Heat Retention: Gravel retains heat from the sun and releases it slowly, which can mask the heat signatures of potential moisture or leaks beneath the surface.

3. Non-Uniform Surface: The uneven texture of the gravel creates inconsistent thermal readings, as the camera may pick up different temperatures depending on the gravel's density or distribution.

4. Environmental Interference: External factors like wind, rain, or shade can affect the gravel’s surface temperature, further complicating the interpretation of infrared data.

5. Material Properties: Gravel does not conduct heat as effectively as other roofing materials, making it harder for thermal anomalies caused by moisture or leaks to reach the surface and become detectable by the infrared camera.

Electrical Impedance (ASTM D7954):

This practice applies to techniques that use nondestructive electrical impedance (EI) scanners to locate moisture and evaluate the comparative moisture content within insulated low-slope roofing and waterproofing systems.

This practice is applicable to roofing and waterproofing systems wherein insulation is placed above the deck and positioned underneath and in contact with electrically nonconductive single-ply or built-up roofing and waterproofing membranes and systems such as coal tar, asphalt, modified bitumen, thermoplastics, spray polyurethane foam, and similar electrically nonconductive membrane materials. This practice is also applicable to roofing and waterproofing systems without insulation placed above moisture absorbing decks such as wood, concrete, or gypsum, that are in contact with single-ply or built-up roofing and waterproofing membranes as described above.

This practice is applicable to roofing and waterproofing systems incorporating electrically nonconductive rigid board insulation made from materials such as organic fibers, perlite, cork, fiberglass, wood-fiber, polyisocyanurate, polystyrene, phenolic foam, composite boards, gypsum substrate boards, and other electrically nonconductive roofing and waterproofing systems such as spray-applied polyurethane foam.

Excess moisture trapped in roofing or waterproofing systems can adversely affect performance and lead to premature failure of roofing or waterproofing systems and its components. It also reduces thermal resistance, resulting in reduced energy efficiency and inflated energy costs. Impedance scans can be effective in identifying concealed and entrapped moisture within roofing or waterproofing systems.

This practice is intended to be used at various stages of the roofing and waterproofing system’s life such as:

during or at completion of installation of roofing or waterproofing system to determine if there was moisture intrusion into the roofing or waterproofing system or underlying materials; at regular intervals as part of a preventative maintenance program; and to aid in condition assessment, or before replacement or repair work, or combinations thereof, to assist in determining the extent of work and replacement materials.

This practice alone does not determine the cause of moisture infiltration into roofing or waterproofing systems; however, it can be used to help tracing excess moisture to the point of ingress.

At the time of the moisture evaluation survey, the roofing or waterproofing surface of the area being surveyed shall be free of debris and dry. Ponded water, snow, ice, rain, debris, and other materials not part of the roofing or waterproofing system shall be removed before testing. The report shall indicate the cleared areas that were surveyed.

Having established the reference location, power the scanner on, place it within the dry reference location, and calibrate it in accordance with the impedance scanner manufacturer’s instructions. Choose the sensitivity range to be used in accordance with the manufacturer’s instructions and zero the impedance scanner’s meter reading. With the scanner powered on and calibrated, sensitivity ranges selected, and meter reading zeroed, position the scanner on the surface of the section of roofing to be surveyed with the scanner’s sensing pads in direct contact with the roofing or waterproofing system surface.

When carrying out moisture evaluation testing, the impedance scanner shall be placed in direct contact with the surface being tested in accordance with the manufacturer’s recommendations. Direct contact between the instrument’s electrodes (sensing pads) and roof surface is required so that there is minimal signal loss as the detection signal passes through the thickness of coverings or coating materials. Take additional readings in areas adjacent to points where elevated readings are indicated.

If the survey is being conducted on an aggregate surfaced roof, the aggregate shall be dry and of uniform thickness. Areas with varying thicknesses of aggregate or moisture or dirt present shall be noted and treated separately. Affected areas shall be dry and additional core cuts shall be taken to determine “dry” reference values for the affected areas.

While performing an impedance moisture evaluation survey, visually inspect and note any visible defects and anomalies such as fish mouths and blistering. Mark anomalies with an indelible marker and record their locations on roof, report sheet, or roof plan.

Limitation of Findings

This report is qualitative in nature and is limited to surface observations and non-destructive testing. The data and findings are subject to interpretation. This report addresses only those components that are present, visible

(both in the visible light spectrum as well as infrared as previously defined), and accessible at the time of inspection. The inspection or report does not imply insurability or warrantability of the structure, nor does it verify compliance with manufacturer’s instructions or code compliance. This inspection may not reveal all deficiencies and is not technically exhaustive of the structure. Items identified in this report do not obligate any party to make repairs or take other actions. Destructive testing must take place at areas indicated to verify any latent moisture.

Pricing for estimates were derived from recent projects and referenced from RS Means 2024, with a 15% cost escalation added and rounded up for clarity. RS Means data is a starting point but can be below actual cost of government projects due to complexity and documentation required of federal projects.