C04_Attachment 4 - Final Inspection Report USDA Stoneville B1 B80 9-27-2024.pdf

141 Experiment Station Road, Stoneville, MS 38776

Investigative Report for Building Envelope Leaks in:

Building 1 – Jaime Whitten Delta States Research Center Asset ID#: 640200B001

Building 80 – National Biological Control Laboratory Asset ID#: 640200B080

Final Investigative Report

September 27, 2024

Investigative Report for Building Envelope Leaks in Building 1 and Building 80

I. Table of Contents

II. Inspection Information

III. General Project and Building Descriptions

IV. Building 1

V. Building 80

VI. Proposed Architectural Repairs

VII. Conclusion

Investigative Report for Building Envelope Leaks

I. Table of Contents

THIS PAGE IS INTENTIONALLY LEFT BLANK

II. Inspection Information

Investigative Report for Building Envelope Leaks

A. Dates of Inspection: 14 ‐ 17 November 2023

B. Name of Facility and Buildings: USDA Agricultural Research Station Building 1, Building 80

C. Building Address: 141 Experiment Station Road

Stoneville, MS 38776

D. Primary Contact Name and Title: J. Kevin Magee, PE Engineering Project Manager

E. Name of Inspectors: J. Trey Thomas PE Ethan J. Barrentine EIT

F. Name of Inspecting Firms: Toland & Mizell Architects, Inc.

590 Means St. NW, Suite 200 Atlanta, GA 30318

Innovative Engineering Inc.

3380 Trickum Road Building 500, Suite 100 Woodstock, GA 30188

II. Inspection Information

Investigative Report for Building Envelope Leaks

III. General Project and Building Descriptions

Investigative Report for Building Envelope Leaks

A. General Project Description

This report summarizes the survey activities performed at Building 1 and Building 80 at the USDA Jamie Whitten Delta States Research Center in Stoneville, Mississippi. The goals of this project are to investigate sources of potential moisture intrusion at the 5th floor and penthouse of Building 1 and the western facing windows in the corridors at Building 80, then to develop a report describing the conditions and a Program of Requirements (POR) document detailing specific requirements which would need to be incorporated into future design and/or construction documents to affect a repair that would remedy the situation.

B. Building 1 Description

Building 1 is located at the northeast corner of the developed area of the of the USDA Stoneville, Mississippi campus and is a total of six stories in height including penthouse levels. The original building drawings are dated 1967 and original construction of the approximately 90,000 square foot building was reported to have been completed in 1972. The building covers a footprint that measures overall 239 feet by 175 feet including lower levels. A tower portion is located at the northern extent of the overall footprint that measures 239 feet by 55 feet and is five stories in height, plus a smaller penthouse area that measures approximately 68 feet by 46 feet.

The structural system of the building consists of a reinforced concrete frame with perimeter strip foundations and isolated pile caps. At the time of the original construction, Building 1 was outfitted with a brick masonry façade with exposed cast‐in‐place concrete accents. Once the building approached 43 years old, an extensive renovation project was undertaken that resulted in the building being stripped of interior finishes, façade elements, and MEP (mechanical, electrical, and plumbing) systems. The building was effectively rebuilt in 2010 with new systems, finishes, a new façade, and the enclosure of balconies located on the north elevation. The new façade consists primarily of new face brick, along with architectural precast concrete accents, new parapets at most locations, and new fenestrations. The roofing system was also replaced during the renovation with new interior roof drains and a new modified bitumen roof membrane.

No extensive renovations or additions affecting the envelope or façade were noted to have been undertaken since the 2010 renovation. However, multiple small‐scale repair operations appear to have been performed since the renovation in an attempt to rectify problems and deficiencies in the renovation workmanship.

C. Building 80 Description

Building 80 is located at the southwest corner of the developed area of the Stoneville, MS campus and is one story in height plus a mechanical penthouse level in the attic space. The original construction of the approximately 56,000 square foot building was reportedly completed in December 2004. The building consists of two laboratory wings, each measuring approximately 260 feet by 95 feet, joined by a center section that houses administrative and meeting facilities measuring approximately 112 feet by 48 feet.

The structural system of the building consists of a structural steel frame with perimeter strip and interior isolated foundations. The roof system is primarily sloped with smaller areas of flat roofs. The sloped roofs are composed of structural steel members with cold‐formed light gauge roof purlins, metal decking, and standing seam roofing panels. The flat roof areas are composed of structural steel framing, metal roof deck, and a modified bitumen roofing membrane. Building 80 has a brick masonry façade with a precast concrete accent band extending around the

Investigative Report for Building Envelope Leaks perimeter of the building at the sloped roof eave height. Rainwater is directed away from the building by gutters at the sloped roof areas and interior roof drains at the flat roofs. No extensive renovations or additions affecting the envelope or façade were noted to have been undertaken since the original construction and any repair activities appear to be very minor and completed by local maintenance.

D. Qualifications and Limitations

Inspection activities on site included observations of interior and exterior walls of the referenced structures.

Observations were typically performed visually and were augmented by the use of sUAS (small Unmanned Aerial Systems, or drones), infrared thermography, and hands‐on investigation to locate and identify deficient conditions in the façade of the building. Physical observations were performed at multiple representative areas of the building façade as well as all parapets. These observations included sounding, probing, water testing, and minorly destructive investigations of the building façade to identify deficiencies and verify possible sources of water ingress and material deterioration.

As a part of this inspection, any structurally unsafe conditions and potential water infiltration sources were noted;

and representative views of these conditions requiring maintenance were identified and documented in the report.

Therefore, while all typical deficiencies requiring maintenance were visually observed in order to quantify them, each typical deficiency and its location was not specifically documented. With the passage of time since the creation of this report, both concealed and visible conditions may have changed due to alterations, additions, renovations, and deterioration. Specific repair procedures are not part of this report. The repair procedures presented herein are solely conceptual in nature. For all aspects of the repairs to be addressed including materials selection and specific methods of repair, construction documents are required.

A certified roof inspection was not a part of this façade inspection; however, deficiencies in the roofing, as it relates to the façade, were noted as well as any obvious defects in the roof. The roof inspection was cursory and should not be considered comprehensive.

The investigation and correction of building envelope deficiencies are often not intuitive or straightforward processes. Oftentimes water, once it has made its way inside a building, can travel in many directions and great distances. When making retrofits or repairs, the correction of one leak can force water into new areas requiring different building components to resist the ingress. The correction of water ingress issues should be considered an iterative process that often takes several rounds of remedial actions to achieve a satisfactory result.

Any water spray testing was performed in general compliance with one or more of the following standards from American Architectural Manufacturers Association (AAMA) or the American Society for Testing and Materials

(ASTM):

AAMA 502 – Voluntary Specification for Field Testing of Newly Installed Fenestration Products ASTM E1105 – The Standard Test Method for Field Determination of Water Penetration of Installed Exterior

Windows, Skylights, Doors, and Curtain Walls

In general, a constant water pressure of between 30‐35 psi is applied from a distance of 12 inches from the surface through a ¾ inch diameter hose fitted with a ½ inch B‐25 #6.030 nozzle. The nozzle is fitted with a pressure gauge to measure the flowing pressure and a distance gauge to maintain the correct distance from the test surface. During the test, a section is chosen and the nozzle is slowly moved back and forth for a duration of five minutes. During the

Investigative Report for Building Envelope Leaks test, a member of the testing team will be inside to monitor and check for any leakage. Any amount of uncontrolled water greater than ½ ounce that appears on any normally exposed interior surface, that is not contained or drained back to the exterior, or that can cause damage to adjacent materials or finishes over the course of 5 minutes will be deemed a failure.

This investigative phase of the work should be considered the first of four phases that include Investigation, Bid Documentation, Bidding, and Construction. This report alone does not constitute a bid document, a scope of work, or construction documents, and should not be used as such.

E. General Building Conditions

Both buildings are in acceptable condition, considering their age and geographic location. Deficiencies noted were typically related to water ingress and appear to be the result of poor detailing during the design phase, poor workmanship during construction, or normal age‐related deterioration and weathering. To determine the extents of the water infiltration an initial walkthrough of the buildings was performed with Mr. Magee, and Mr. Roger Bright, who works at the facility.

Building 1 ‐ At the 5th floor of Building 1, multiple locations of water‐stained ceiling tiles and sporadic evidence of water damaged gypsum walls were noted. The problem areas were categorized by their location and construction.

1. SE Elevation Windows – These windows were specifically mentioned in the Project Requirements

Document. A visual inspection from the inside of the structure revealed heavily stained ceiling tiles in Copy/Work Room 525, and isolated occurrences of stained ceiling tiles in other offices along the east end of the 5th floor. Although there is evidence of water ingress on interstitial and interior building components in Room 525, extensive water testing of the southeast elevation windows did not reveal any leaks.

Investigation indicated that damaged ceiling tiles in the other offices were caused by leaking valves, condensation on chilled water piping, or other mechanical sources.

2. Doorway at North Penthouse Elevation – Mr. Magee indicated that water previously entered the penthouse at a double door in the north penthouse elevation. He indicated remedial work had been performed at the door that appears to have corrected the issue. During water testing activities at the penthouse, water flowing down the north penthouse elevation did not appear to cause water ingress issues, but a more direct water spray would result in water entering around the door perimeters.

3. Northwest Penthouse Elevation/5th Floor Breakroom – Water‐damaged ceiling tiles were noted in the 5th

Floor Breakroom. It appears that previously, water was able to enter the penthouse at the parapet near the north end of the west elevation. Mr. Magee and Mr. Bright indicated they had seen water entering through cracks in the roof slab and running down the interior penthouse wall. For this to occur, water has to enter the space below the roof membrane. This water collects at the northwest corner of the penthouse and migrates through the concrete structure, into the breakroom below. Water testing at the northwest corner of the penthouse did not result in any water entering the building.

4. Leaks at 5th Floor Roof Drains – Leaks were reported at multiple roof drains by the building occupants and evidence of a leaking drain was noted at the drain above Room 504. These drains were not listed in the scope in the Project Requirements Document but appeared visibly leaking so they were investigated.

Although water spray testing did not result in any water ingress, water intrusion was noted at two drains

Investigative Report for Building Envelope Leaks during static water testing. It appears that the roof drains were not installed properly, and sealant was omitted beneath the drain assembly upper clamp ring.

5. Potential Roof Leaks at 1st Floor – Mr. Magee and Mr. Bright indicated two potential leaks in the hallway at the first floor, near Room 150 and Room 154. Our investigation determined both leaks are due to condensation on mechanical ductwork in the second‐floor mechanical room.

Building 80 ‐ At the flat roof corridors north and south of the center section of Building 80, extensive evidence of long‐term water ingress was noted. Water‐damaged ceiling tiles and drywall were noted in finished spaces, and water staining was noted on beams, joists, and metal decking in the interstitial space above the suspended acoustical tile ceiling. During the investigation, several deficiencies were investigated and are listed below:

1. Parapet to Pitched Roof Transitions – One end of the west parapets of both the north and south connectors terminates into a pitched roof. It appears that very little direction in the detailing of these transitions was provided in the original construction documents and the sheet metal flashing installed during the original construction is not adequate to prevent water from entering the building during heavy directional rainfall. These areas appear to be a large contributor to the leaks noted in the connecting corridors. To repair this condition, flashing details need to be developed and installed.

2. Brick Wall Flashing Transitions – At the other end of the corridor parapets, adjacent to the Center Section, the exterior wall parapets terminate into a brick wall that extends away from the exterior of the building.

In these two locations, the brick wall is supported by structural steel beams as the wall extends into the sloped center section roof. Although flashing in the area where the wall is above the flat roof was shown on the original drawings, no direction regarding flashing where the wall is over the sloped roof was provided. Any water entering the air space behind the brick has no means of exfiltration and is forced into the building interior. These leaks, along with the leaks mentioned above, appear to be the source of the water ingress issues in the connecting corridors. Similar to the other end of the parapet, flashing details need to be developed for this area and installed. In the interim, it may be possible to reduce the amount of water entering the building by sealing the area, preventing water from infiltrating into the airspace.

3. Water Ingress Into Conference Room 201 – A conference room located southwest of the center section and adjacent to the corridor exhibited extensive water staining of ceiling tiles in the field and perimeter of the ceiling. Dr. Maria Rojas (Guadalupe) reported that the roof has leaked within the past two years, mainly in intense rainfall events. At the perimeter, it appears water enters the building at the parapet mentioned above, and travels along structural members, eventually falling to the ceiling tiles below. In the field of the ceiling, the locations of stained ceiling tiles were correlated with mechanical coils or ductwork in the interstitial space above the ceiling. It appears the staining is caused by condensation forming on this mechanical equipment and falling to the ceiling tiles.

4. Water Ingress Into Multi‐Purpose Room 202 – A room located southeast of the center section and adjacent to the corridor exhibited water staining of several ceiling tiles at the perimeter of the ceiling. At the east wall, it appears previous leaks at the rear of the parapet allowed water to enter the building, travel along structural members, and fall to the ceiling tiles below. Water testing in the area did not indicate breaks in the building envelope and it appears that a roof replacement in 2016 has corrected this issue. In the ceiling along the south wall, the location of stained ceiling tiles correlated with mechanical pipes in the interstitial space above the ceiling. It appears the staining is caused by condensation forming

Investigative Report for Building Envelope Leaks on this mechanical equipment and falling to the ceiling tiles.

5. Miscellaneous Leaks Beyond the Scope Area – During an interview and walkthrough with Dr. Maria

Guadalupe, she pointed out multiple locations where water was entering the building. These include around doors at the loading dock, at the roof at the rooftop mechanical areas, and at multiple exhaust penetrations in the slopped roof area. These issues are outside the scope of this project and should be evaluated and a properly designed repair applied.

Investigative Report for Building Envelope Leaks

IV. Building 1

Investigative Report for Building Envelope Leaks

A. Building 1 Investigation

As stated earlier, Building 1 is in acceptable condition, considering its age and geographic location. Deficiencies noted were typically related to water ingress and appear to be the result of poor detailing during the design phase, poor workmanship during construction, or normal age‐related deterioration and weathering. To determine the extent of the water infiltration an initial walkthrough of the building was performed with Mr. Magee, and Mr. Roger Bright, who works at the facility. On the 5th floor of the building, multiple locations of water‐stained ceiling tiles and sporadic evidence of water‐damaged gypsum walls were noted.

During the investigation, several instances of water‐stained ceiling tiles were noted that were reported to have been in place since the renovation. Some of the sources of staining were determined to be caused by leaking mechanical devices or condensation on chilled water piping or HVAC equipment. The investigation required the removal or displacement of many of the stained tiles. After the investigative activities were completed, replacement ceiling tiles from attic stock were installed in the 5th floor hallway, the breakroom, and in Copy Room 525. This will allow monitoring for when new or continued leaks stain the replacement tiles.

The investigation concentrated on four main areas. They are as described in the sections below:

B. Southeast Elevation Windows

The 5‐story portion of Building 1 has a row of ribbon windows at the 5th Floor, extending from the center section to near the end of the wing (see Photo 1). This ribbon is composed of 8 vision windows serving offices and 16 panes of opaque spandrel glass. All of these panes are located below 24 panes of shorter spandrel glass. Vision panes are typically 3’‐4” wide by 6’‐0” high and spandrel panes are 3’‐10” wide by 6’‐0” high. The spandrel glass above is always the same width as the pane below and is two feet high. Atypical width panels are provided at each end of the ribbon.

The construction of the windows consists of one‐inch insulated glass panes set in aluminum frames with pre‐molded gaskets at the top and bottom and wet‐applied sealant at the vertical seams.

Photo 1: Building 1 Southeast Elevation Photo 2: Building 1 East Wing Roof

Investigative Report for Building Envelope Leaks

The windows span vertically between a steel angle at the head to brick masonry at the sill. A sub‐sill appears to be set in mastic and is located between the window sill and the brick masonry. Sealant was noted at the head joint and corrugated weeps were installed above the lintel oriented vertically and located approximately every two feet.

The window installation appears to differ from the 2010 renovation drawings in several ways.

1. The window head details (1&2/A8‐4) indicate flashing to be installed between the structure and the lintel angle, terminating at the horizontal toe of the angle. This flashing was not observed.

2. The window sill details (8&9/A8‐4) indicate the support of the window sill is an architectural precast panel.

In the as‐built condition, brick masonry supports the window sill.

3. All the window head and sill details dealing with window installation in masonry indicate all window frames are to be inset from the face of brick by ¾ inches except one. Detail 1 on sheet A8‐4 indicates the window frame is to be installed flush with the face of brick. In the as‐built condition, the window frames are typically positioned flush with the face of brick (see Photo 3) with isolated areas of the window frame positioned slightly proud of the brick.

Photo 3: B1 Window Head Flush with Brick Figure 1: B1 Section at Window

On sheet A1‐5 of the 2010 renovation drawings, section cuts refer to wall sections 1 and 2 on sheet A3‐3. On sheet A3‐3, for information above the fifth‐floor windows, detail 1 refers to detail 1 on sheet A3‐15 and detail 2 refers to detail 2 on sheet A3‐15. On sheet A3‐15, detail 1 (see Figure 1) shows the intended configuration of the vision windows, brick masonry, and original structural frame of the building. Detail 2 on sheet A3‐15 is intended to show a similar configuration at the spandrel glass but is labeled “Not Used.”

The as‐built condition appears to be in general conformance with the design drawings, though the following discrepancies were noted:

1. At the joint between the brick and the underside of the concrete beam, no direction was provided in the architectural drawings. The as‐built condition is a 5/8‐inch sealant joint.

Investigative Report for Building Envelope Leaks

2. The flashing installed above the existing concrete beam is present, but the lap joints were noted to be around two to three inches. Although none of the renovation specifications were available for review, lap joints of this type are usually specified to adhere to requirements of the “Architectural Sheet Metal Manual” published by the Sheet Metal and Air Conditioning Contractor’s National Association (SMACNA).

The SMACNA documents typically require a minimum of four inches of lap with sealant at joints of this type.

3. Sealant has been installed between the flashing above the existing concrete beam and the brick. The workmanship of this sealant installation is poor, and it does not appear to be necessary or functional. It was apparently installed after the renovation construction was completed.

Users reported that water has been entering the building during very specific conditions since the renovation. These conditions include times when a hurricane or tropical storm passes to the west of the site, and the counterclockwise rotation of the storm causes intense rain to be driven towards the south elevations of the building. Typical wind‐ driven rain droplets can reach an angle of 20 degrees from vertical. Beyond that, air resistance becomes significant and droplets tend to break apart, creating a finer matrix that can travel at up to 70 degrees from vertical in extreme conditions. Although leaks in this area had not been reported in several years, the occupants indicated that it was likely a lack of conducive conditions.

During the investigation in the interstitial space above the acoustical tile ceiling, evidence of water ingress on interior building components was noted. It appears water enters the building in two locations, the area between the window head and the concrete beam, and through penetrations and cracks in the concrete roof slab. However, extensive water testing of the southeast elevation windows did not reveal any leaks. Areas tested included the roofing within 10 feet of the parapet, the back of the parapet, the intersection of the parapet and penthouse wall, coping, brick and precast masonry above the windows, ribbon windows, and brick below the 5th‐floor windows. During the most intense water testing, even water spray exceeding established testing requirements applied at angles that could not occur naturally did not result in water entering the building envelope.

Water ingress appears likely in the area of the flashing joints above the concrete beam. Water entering this location, or in other areas of the coping and parapet, enters the area above the concrete roof slab and under the roofing membrane. Water in this space is free to travel in multiple directions and will flow until it reaches a location where it can penetrate the roof slab. Water staining was noted at two penetrations and a crack at the underside of the roof slab in the area of the Copy/Work Room, Room 525 (see Photos 4 & 5).

Investigative Report for Building Envelope Leaks

Photo 4: B1 Water Staining at Crack Photo 5: B1 Water Staining at Conduit Penetration

It appears that remedial activities have been performed at these locations and it was undetermined if the areas were still actively allowing water to enter the building. Although the dates of the remedial activities were reported to not be known, one iteration of repairs was likely performed as the result of warranty repairs after the renovation.

If the water staining had been caused by water entering the space beneath the roofing membrane, remedial activities performed on the roofing may have slowed or halted the ingress. It appears that multiple generations of roof patching activities have been performed over time (see Photos 6 & 7).

Photo 6: B1 Roof Patching with Black Mastic Photo 7: B1 Roof Patching with Gray Mastic

C. Doorway at North Penthouse Elevation

Water ingress at the double doorway in the north penthouse elevation was reported by Mr. Magee, and water‐ damaged finish building materials were noted in the penthouse and 5th floor area beneath the penthouse wall.

Water staining was noted to be concentrated in the hallway and Rooms 520 and 524. It appears water had been

Investigative Report for Building Envelope Leaks running down the north penthouse elevation, dripping off the door head, impacting the door sill, and being driven horizontally under the door both between the door and threshold and between the threshold and rough opening.

Once inside, the water traveled to the chase area adjacent to the door and down to the 5th Floor. Mr. Magee indicated that remedial work had been performed on the door and the leaks had largely been eliminated.

Water testing was performed at the door, and it appears that the remedial activities have succeeded in preventing water running down the north penthouse elevation from entering the building. However, stronger rain directed towards the door will cause water to enter the building under the door and at the joint between the two door halves.

This amount of rain is not typical and should be expected to occur during times of heavy wind‐driven rains with winds from the north.

D. Northwest Penthouse Elevation/5th Floor Breakroom

Water ingress at the northwest corner of the penthouse was reported by Mr. Magee, and water‐damaged finish building materials were noted in the 5th‐floor breakroom area below. Water staining was noted to be concentrated at the east end of the breakroom area, adjacent to the wall. It appears water has been entering the penthouse at the roof level via cracks in the concrete roof slab, running down the interior of the west penthouse wall, collecting in the northwest corner of the penthouse interior, and infiltrating through the penthouse floor slab, into the breakroom area below.

On the Penthouse Roof Plan, plan 2 on sheet A1‐6 of the 2010 renovation drawings, there are no section cuts at the northwest corner of Building 1. There is what is assumed to be a typical wall section cut referring to detail 6 on sheet A3‐13. There is also a section cut at the overflow scupper referring to detail 5 on sheet A3‐15. On sheet A3‐13, detail 6 (see Figure 2) shows the intended configuration of the penthouse parapet, architectural precast concrete (APC) panel, and original structural frame of the building. The detail shows the architectural precast set inward two inches from the face of the concrete beam. The actual offset of the as‐built condition varies considerably around the perimeter of the penthouse, varying up to 1.5 inches along the west wall. Though measuring equipment accurate enough to conclusively verify the case was not available at the time of the investigation, it appears the structural frame of the building is out of square (see Photo 8), while the brick and APC were installed square with the balance of the building. It does not appear that this out of square condition affects the continuity of the building envelope or is a factor in the water ingress. The flashing between the APC and the concrete beam was noted to be sloping towards the building at several locations and the lap joints were noted to be short, similar to the same condition at the 5th‐floor ribbon windows.

Investigative Report for Building Envelope Leaks

Figure 2: B1 Detail at Penthouse Parapet

Photo 8: B1 Out of Square Building Frame

Water testing was performed at northwest corner penthouse wall, from the base of the penthouse up to the parapet coping, down the inside of the parapet wall, and onto the roof. The majority of the northwest roof quadrant was tested. A large amount of bird excrement, seeds, and debris was located on the penthouse roof which caused water to back up at the roof drain. No water was noted inside the penthouse or at the 5th‐floor breakroom during testing.

Water entering the penthouse through the crack in the roof slab must come from the area between the roof membrane and the roof slab. For water to be in this area, a breach of the roofing membrane, flashing, or parapet coping must exist or, water could enter through the flashing at the base of the APC. A breach could exist virtually anywhere in the parapet or roofing as water in this space is free to flow until it reaches a location where it can penetrate the roof slab. All of the roofing, coping, flashing, and penetrations at the penthouse were visually inspected and no obvious deficiencies were noted.

E. Roof Drains

The 5‐story portion of Building 1 has five roof drains in an east‐west orientation (see Figure 3), and Mr. Magee and Mr. Bright both report that leaks had occurred at some of the roof drains. During the walkthrough, we inspected the underside of the roof slab at the west drain from Room 504. A water‐damaged ceiling tile was noted beneath the drain and there was water staining on the concrete.

Investigative Report for Building Envelope Leaks

Figure 3: B1 Roof Drain Locations

The roof drain assemblies appear to be a Josam Series 21500 drain assembly with a cast iron dome (see Photo 10).

Detail 19 on sheet A3‐00 of the 2010 renovation drawings shows the drain installation detail. See Figure 4. When observing the installation of the drains, the new openings appeared to be very roughly cut (see Photo 9) and the sealant indicated in the above‐mentioned detail was not present. Debris was present at each drain. The amount of debris noted indicated that regular drain cleaning is not a part of the scheduled building maintenance but was not enough to restrict runoff evacuation to the point of water entering the secondary scuppers.

Figure 4: Detail 19/A3‐00 of 2010 Renovation Drawings. Missing Sealant Highlighted.

Photo 9: B1 Roof Drain From Underside Photo 10: B1 Typical Roof Drain with Dome Removed

West West Central East East Central Central

Investigative Report for Building Envelope Leaks

Although the roof drains were not part of the scope, all of the roof drains were cleaned and water tested during this investigation. The inspection team cleaned each drain by removing the dome and flushing any collected debris into the drain. The first phase of water testing included water spray testing. Spray testing was conducted at the west, west central, and center drains. The spray testing included removing the strainer and directing water spray at varying angles at the drain components both above and below the roofing membrane. The results of the spray tests indicate falling rainwater is not the source of the leaking drains.

After the spray test, a static water test was performed. For this test, the opening in the roofing membrane was covered and water was applied to the area above the roofing. The covered opening allowed water to accumulate on the roof, creating static head pressure on the drain components above the membrane. During this test, leaks were primarily noted at the west drain, with a very minor leak noted at the east drain. A summary of the static head water testing is shown in Table A.

Table A – B1 Roof Drain Static Head Water Testing

Drain Room Head ~Qty Notes

West 504 3.5” 70 gal Leak originating from crack at underside of slab.

West Central

510 3.5” 80 gal No leaks in 510 or adjacent 514.

Center 520 4.5” 110 gal No leaks.

East Central

526 4.0” 184 gal No leaks.

East 536 4.5” 80 gal 1 drop observed at insert in underside of slab.

During the water tests, the inspection team serviced each drain by removing each dome and flushing any collected debris into the drain. After the testing, our team attempted to disassemble the west drain, over Room 504, but one of the fasteners appears to be corroded to the point that the bolt will break before it can be removed.

Even though the sealant was omitted during the original installation, the results of the water testing indicates water ingress only occurs during periods of heavy rain when there is a partial drain blockage. Removing the clamp ring and installing sealant would likely prevent this ingress, but if the clamp ring fasteners break, the entire bowl assembly will have to be removed in order to access the broken fastener. Recommendations for the roof drains at this point are to leave them as is and implement a regiment of regular drain cleaning.

Investigative Report for Building Envelope Leaks

F. Potential Roof Leaks on 1st Floor

Mr. Magee and Mr. Bright indicated two potential leaks in the hallway on the first floor, near Room 150 and Room

154. Our investigation determined both leaks are due to condensation on mechanical ductwork in the second‐floor Mechanical Room 246. The staining adjacent to Storage Room 154 is caused by condensation on the AHU‐3 oval supply duct at the south side of Room 246 (see Photo 11) and the staining adjacent to Tel Equipment Room 150 is caused by condensation on the AHU‐2 oval supply duct at the east side of Room 246 (see Photo 12), near an abandoned doorway in the east wall. It appears that condensation forms on the ductwork in the mechanical space and collects on the floor slab around the duct penetration through the floor slab. The water then infiltrates through the concrete, runs down the ductwork, and falls to the top of the ceiling tiles in the hallway.

Photo 11: B1 Duct above Hallway near Room 154 Photo 12: B1 Duct above Hallway near Room 150

Investigative Report for Building Envelope Leaks

V. Building 80

Investigative Report for Building Envelope Leaks

A. Building 80 Investigation

Building 80 consists of 2 laboratory wings and a center section (see Photo 13). These three areas are joined by two connecting corridors. As stated earlier in this report, the building is in acceptable condition considering its age and geographic location. The building appears to have a few concentrated problem areas where issues can be traced back to deficiencies in the original construction. Deficiencies noted were typically related to water ingress and appear to be the result of poor detailing during the design phase and poor workmanship during construction. To determine the extent of the water infiltration, an initial walkthrough of the building was performed with Mr. Magee, and Mr. Bright. Multiple locations of water‐stained ceiling tiles and evidence of water damaged gypsum walls were noted along the west walls of the north and south corridors adjacent to the center section of the building. Water‐ stained ceiling materials were also prevalent in Conference Room 201. Other minor areas with apparent water damage were noted throughout the building that were either not severe or were in areas not covered under the scope of this project.

Water spray testing was performed at both connecting corridors, including the wall, windows, parapet, coping, flashing, and roofing. These areas were also tested at the south and west elevations of Conference Room 201. In general, the building envelope system appeared to work as designed and shown in the contract documents. An example is at the center of the west elevation of the south connecting corridor where there is a vertical crack in the masonry above the window. Water spray testing indicated any water penetrating beyond the crack and face of the masonry in this location is directed to the exterior at the flashing above the window lintel. Although the weeps in this area appeared to often be non‐functional due to debris, water was still able to exit to the exterior through the mortar joints. Other areas exhibiting poorer performance are described in the sections below:

B. Parapet to Pitched Roof Transitions

Water ingress has been a concern at the west elevation of both the north and south corridors since the original construction was completed. Originally, water would only find its way inside during severe rain events. However, the condition has worsened to the point where even a light rain may cause water ingress.

Photo 13: Building 80 Overall View Photo 14: Building 80 Scope Area

Water testing was performed in the corridor area in question and several problem areas were identified. One of these locations is where the east parapet of Conference Room 201 intersects the flat roof of the corridor and the

Investigative Report for Building Envelope Leaks sloped roof of the Center Section (see Photo 14, Area As, and Photo 15). Water ingress as a result of water testing was also noted in the similar opposite area on the north side of the center section, above the Research Lead Office 105 and the adjacent reception area (see Photo 14, An, and Photo 16). These two areas are constructed in an equal but opposite fashion and the issues on one side are present at the other. Going forward, any comments that do not specifically indicate north or south should be taken as applying to both areas.

Through an investigation of the as‐built condition and review of the existing documents, it appears the water management path in place in the area where the parapet is positioned over an adjacent roof only allows water that has entered the brick air space to exit within the building. In these areas, there appears to be through wall flashing under the coping, and then no other flashing between the sheathing and brick. Water entering this space travels down, in the air space, and onto the structural steel beams below. Once on the beams, the water travels and spreads out horizontally on the top flange until enough collects to spill over. Some of this water falls to the top of the ceiling tiles, while the rest lands on the top of the bottom flange, where it travels and spreads out horizontally until it collects sufficiently to spill and fall into another area. This sequence was noted to be the primary mechanism of water ingress at the west elevations of both the northern half of the southern corridor and the southern half of the northern corridor.

Photo 15: B80 South Parapet to Center Section Interface Photo 16: B80 North Parapet to Center Section Interface

To properly remedy this condition, the coping and brick in the area will likely require removal. This will allow through‐wall step flashing to be installed where the parapet intersects the sloped roof and horizontal through‐wall flashing installed at the flat roof. This flashing should direct any water in the air space to the exterior, above the plane of the roof, through weeps installed above the flashing when the brick is reinstalled. Before repairs of this type are performed, the flashing system should be properly designed and the conditions should be thoroughly detailed, including upper and lower terminations and transitions.

As an interim measure, some success may be realized by minimizing the amount of water entering the air space.

This can be accomplished by repointing any brick joints that are not tight, sealing any potential ingress points at the coping, and applying a penetrating water‐repelling silane type material.

C. Brick Wall Flashing Transitions

Another source of water ingress found during water spray testing was at the opposite ends of the connecting

Investigative Report for Building Envelope Leaks corridors than the issues discussed above. These locations occur at both the north (see Photo 14, north of Bn) and south end (see Photo 14, south end of Bs) of the west corridor parapet where it connects to either adjacent wing.

At these two locations (See Photos 17 & 18), sheet metal flashing has been formed and welded to make a transitional piece to bridge the gap between the end of the parapet and the sloped standing seam roof. This piece is in poor condition at the south corridor and neither end is configured in a way that will prevent driven rain from penetrating the building envelope.

Photo 17: B80 South Parapet‐Roof Interface Photo 18: B80 North Parapet‐Roof Interface

In Photo 17, a broken weld can be seen at the top of the vertical side of the transition piece, and there is no lap at the base where the vertical intersects the sloped surface. Water spray testing in these locations resulted in water penetrating the building envelope.

Photo 19: B80 Water Spray Testing Straight Down Photo 20: B80 Water Spray Testing Normal to Roof Surface

At the sloped portion of the transition, water spray testing resulted in varying amounts of water ingress. It appears the lap length, the length of flashing that extends beyond the beginning of the standing seam roofing, is not adequate to prevent rainwater from entering the building. Water testing simulating heavy vertical rainfall (see Photo 19) resulted in a small amount of water entering the building that would wet the ceiling tiles and, likely

Investigative Report for Building Envelope Leaks cause a drip after several hours of activity. When water spray was directed at an angle normal to the roofing surface (see Photo 20), copious amounts of water entered the location (see Photo 21). This amount of ingress would likely result in water dripping from the ceiling tiles after just a few minutes. Fortunately, directional rainfall of this intensity is not a common occurrence.

Potentially severe weather was forecasted for the area several days after the site investigation concluded. In an effort to prevent at least some amount of water ingress, the design team installed sealant in the joint between the flashing transition piece and the standing seam roofing at the north corridor (see Photo 22). On November 21, 1.5 inches of rain with wind gusts up to 18 miles per hour were recorded less than 10 miles away, in Greenville, MS. It is typical for Dr. Maria Rojas (Guadalupe) to document areas and dates of water ingress. It is recommended to verify with Dr. Rojas if any water ingress was noted at the west side of the north end of the north corridor during this time. This sealant should not be considered a permanent fix. The bead of sealant was surface applied, minimal surface prep was performed, and the installation likely will weather quickly.

Photo 21: B80 Water Leak from Spray Testing at Flashing Photo 22: B80 Sealant Installed at Flashing

For a permanent solution, a new, properly designed flashing transition piece will likely be required. This piece should interface solidly with the parapet and should lap beneath the roofing an adequate distance to prevent driven rain from climbing the slope. Sealant could be integrated into the detail between the flashing and the underside of the standing seam roofing. Sealants in this location can provide a barrier against water intrusion while being protected from damaging ultraviolet sun rays.

D. Water Ingress Into Conference Room 201

Evidence of water intrusion was noted in the ceiling tiles and interstitial space above Conference Room 201. The roof over this room was replaced in 2016. It was reported that shortly after the roof replacement, new ceiling tiles were installed in the room. At the time of this site visit, there were multiple ceiling tiles with water staining (see Photo 23). Our investigation indicates all the water staining in the middle of the room is the result of condensation forming on a central cooling coil and radiating ductwork in the interstitial space. There was evidence of water ingress on the structural steel framing along the south parapet (see Photo 24) with a water‐ stained ceiling tile below the most severe area. Extensive water spray testing along the parapet did not result in

Investigative Report for Building Envelope Leaks any apparent breaches in the building envelope. It appears that water entering the building at the Parapet to “Pitched Roof Transition,” Item B, above, is likely allowing water to enter the area and travel along the top of the beam under the west parapet. It is likely that remedial work for Item B, described above, will stop this ingress.

Condensation in the interstitial space appears to be the major contributing factor to stained ceiling tiles in the central portion of the room. A similar condition exists in the area opposite the conference room in Research Lead Office 105 and the adjacent reception area. A mechanical consultant should be retained to determine the viability of reconfiguring the HVAC system to partially condition the air in the interstitial space above these rooms, allowing the cooling coils to reduce the humidity in the interstitial space to a point that prevents the formation of condensation on the coil pan and ductwork.

Photo 23: B80 Water Stained Ceiling Tiles in Room 201 Photo 24: B80 Corrosion on Steel Framing in Room 201

E. Water Ingress Into Multi‐Purpose Room 202

Two areas with water‐stained ceiling tiles were noted in Multi‐Purpose Room 202 (see Photo 14, Area Cs). One area is along the east wall, beneath the east parapet (see Photo 25), and the other is along the south wall (see Photo 26). It appears the stained ceiling tiles along the east wall are from a leak that was corrected during a 2017 roof replacement. Occupants reported the staining has likely been present since before the roof replacement and water testing did not result in any water ingress.

Investigative Report for Building Envelope Leaks

Photo 25: B80 Water Stains at East Wall, Room 202 Photo 26: B80 Water Stains Below Chilled Water Lines, Room 202

The water staining on ceiling tiles along the south wall of Room 202 was determined to be caused by condensation on ductwork and chilled water lines located above the staining. A similar condition was also noted in Mail Room

107. In this room, water‐saturated insulation was noted on ductwork resulting from condensation. Similar to Room 201, conditioning the air in the interstitial space to the point where humidity levels are low enough to prevent condensation would reduce or eliminate these mechanical sources of water damage.

F. Miscellaneous Leaks Beyond the Scope Area

During a walk‐through with Dr. Maria Rojas (Guadalupe), several areas with water damage from water ingress from the exterior, condensation, or other mechanical sources were noted. This includes:

1. Water ingress from multiple roof vent pipes. Daylight can be seen from the attic space at several of these roof penetrations (see Photo 27). Occupants reported that local maintenance had attempted to correct these leaks with little success.

2. Water ingress at the roof mechanical areas at the north and south wings (see Photo 28). These appear to be flashing and membrane related. Water beneath the roofing membrane was noted.

3. Water leak at the exterior door in Fermenter Room 246. This appears to be caused by improper or deteriorated weatherstripping.

4. Water leak at the exterior door in Bioreactor Room 248. This appears to be caused by improper or deteriorated weatherstripping.

Investigative Report for Building Envelope Leaks

Photo 27: B80 Vent Penetration at North Wing Photo 28: B80 Saturated Roofing & Ponding at North Wing

These issues were not within the scope of this project and were only given a cursory, visual evaluation. It is recommended to complete a complete, thorough investigation to determine the cause and proper remedial action required at these locations.

Investigative Report for Building Envelope Leaks

VI. Proposed Architectural Repairs

Investigative Report for Building Envelope Leaks

With respect to architectural repairs for parapets and walls generally protruding above and through the roof, a series of repairs are recommended. The issues are generally a direct result of differential movement between the masonry and steel construction components over time. Our team noted that some alterations had been proposed during construction for the areas of concern, but the associated documentation was not available to the team.

Initially we noted a series of hairline fractures in parapet masonry above the roof. Repairs for this purpose could include retooling for a significant number of the exposed mortar joints, or perhaps a simpler process of application of a water‐ repellant product similar to siloxane.

One of the more notable areas involves a series of taller brick parapets which protrude for both the sloped metal paneling roofing as well as the single‐ply membrane roofs. Leaks were not noted in the membrane roofs at low parapets.