November 8, 2004

35 Public Square Elizabethtown, KY 42701 Phone: (270) 737-4226 Fax: (270) 737-0441

July 20, 2018 (Revised July 23, 2018) Mr. Vince Vetter JRA Architects 829 East Market, Suite B Louisville, KY 40206 RE:

STRUCTURAL REVIEW REPORT Kathryn Winn Primary School Carrollton, KY 41008 Structural Assessment of Tectum Roof System 2017-1507

Dear Vince, On Friday July 13, 2018, we were notified that the roofing contractor had discovered an issue with the tectum roof system, on the North side of Phase 1B, where they were working (see Figure 1). As the workers were removing the shingles one of the tectum panels fell damaging an electrical conduit below. As we understand it, the worker stepped on the ½” plywood nailing base and it flexed or broke through dislodging the tectum panel from the bulb-T supports. These panels are 3” thick panels approximately 2’-6”x4’-0” weighing approximately 60lbs to 70lbs. The roofing contractor quickly removed the plywood nailer so that the actual condition and probable cause could be evaluated. By 11:00 Friday July 13th, photos of the tectum panel installation were forwarded to ICON for review. From these photos, the following was apparent: 1. The panels had not been properly grouted solid with only what appeared to be cement mortar on the top of the bulb-T. See Figure 2 for a graphic representation of what the grouted section should look like. 2. The lack of proper grouting has allowed the bulb-T to rotate such that there isn’t enough bearing for the panels. See Photo 1. The grout provides two functions: a) an interlock with bulb-Ts to resist uplift and b) the grout provides lateral stability to the bulb-T to resist shifting and rotation under load. 3. The panels were installed without the proper relief cut for grouting. See Figure 2. These panels were simply the wrong type panel for a bulb-T type installation. Based on prior experience with tectum bulb-T installations and the evidence of the photos provided by Wehr Constructors, by the end of that Friday, ICON Engineering had concluded that the system had been improperly installed. Subsequently while this condition was being evaluated by ICON Engineering, Wehr Constructors had discovered several other panels that appeared to be loose rendering them a hazard.

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By the end of the day of Friday July 13th, a 3” steel decking system had been selected by ICON Engineering for pricing by Wehr Constructors. Additional criteria for installation of the steel decking was provided over the following days leading up to our on-site review. This tectum panel system was used in the original 1960s construction over the Cafeteria, flat roof areas adjacent to the Cafeteria and areas defined as Phase 1B and Phase 1C. However, all four areas appear to use the same type panels yet in different ways: 1. The tectum installed in the flat roof areas was installed in long (possibly 20ft sections) panels spanning over steel bar joists (trusses). These panels are clipped down with steel clips. See Photos 3 and 4. This installation does not use the bulb-T system for support of the tectum. 2. The tectum installed over the cafeteria was installed using a similar length panel as seen in the Phase 1B and Phase 1C areas however, the same bulb-Ts were not used in this area as in the Phase 1B and Phase 1C areas. The support steel in this area could only be viewed from the underside. The top could not be viewed without removing the roofing materials. The support steel however, by visual inspection, was obviously heavier and wider leaving us to believe that the support structure is actually a wide flange beam. Although we could not confirm the exact type of support structure, we saw no evidence for concern. The system will be reviewed again once the existing roofing is removed in a future phase. See photo 6 for an interior view of the roof structure and tectum decking installation. 3. The Phase 1B and 1C tectum and bulb-T system can be seen in photo 5. A site visit was performed by ICON Engineering, on Thursday July 20 to confirm our initial opinions and proposed solution while reviewing other areas to determine if they were safe for occupancy. As indicated above, the Phase 1C area is of the same construction as Phase 1B area where the initial tectum issues were discovered. At least 2 conditions were observed indicating that the tectum in this area is also unstable. Photo 7 shows a panel in the Phase 1C area that has dropped approximately 1 ½” to 2” and could possibly fall. As also noted above, the Cafeteria roof appeared to be structurally sound and safe for occupancy with the more robust panel support system. During the on-site review, what was supposed to be grout, was confirmed to be a cement based sanded mortar and is likely the same mortar that was used on the brick. Even if the relief cuts were properly provided in the tectum panels, this mortar would have not flowed properly into the relief areas. The grout required for this system is highly fluid and would fill the relief areas and flow into the voids of the panel. In August of 2017, ICON Engineering performed an on-site review to determine if the steel trusses were capable of supporting the additional load of the proposed insulated roof system. This site review was limited to field measurements of a single truss as the truss system was simply repeated throughout the Phase 1B and 1C areas. The issues uncovered, after the roofing contractor stepped through the roof, were not obvious from the underside of the tectum system. There were no obvious issues with the tectum decking in the immediate area where our field measurements were taken. Only after the removal of the roofing materials, were we able to understand the defects in the tectum panel installation. This was a hidden issue that could not be known or understood without inspecting it from the top side. I’m very Page 2 of 11


thankful that the roofing contractor found this issue as there is nothing more important that the safety of the children and teachers that occupy these classrooms. RECOMMENDATION FOR REPAIR The recommended repair for the Phase 1B and Phase 1C areas is to remove the existing tectum decking system and replace it with a 3” 20ga decking spanning two truss bays at minimum. The decking will be welded to the existing steel trusses or anchored with an equivalent powder actuated fastener. These professional opinions and recommendations are based solely on information gathered from our onsite review/observations and limited analysis. We reserve the right to supplement or amend these findings and/or opinions should new information become available. Please let us know if you have any questions or need further clarification regarding the above.

Sincerely,

Michael S. Childers, PE President/Structural Engineer Providing Structural Engineering Services for Over 30 Years

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Figure 1: Phasing Plan

Figure 2: Typical Tectum plank with grouted bulb-T supports

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Photo 1: Typical tectum plank with rotated bulb-T – the panel to the left is only bearing on the bulb-T 3/16” to 1/4”. Also note that there is not relief cut for the grout as shown in Figure 2.

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Photo 2: Typical top view of the tectum planks and bulb-Ts. Note that without the relief cut (see Figure 2), it was impossible for the sides of the bulb-Ts to be properly grouted.

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Photo 3: Typical tectum installation over the flat roof bar joists (steel trusses). Note the metal clip bent around the top chord of the bar joist to anchor the panel system to the supporting structure.

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Photo 4: Close up view metal clip bent around the top chord of the bar joist to anchor the panel system to the supporting structure.

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Photo 5: Phase 1B and Phase 1C roof construction with sloped steel trusses and tectum decking spanning between bulb-Ts

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Photo 6: Cafeteria roof structure with tectum panels and possible wide flange beam support structure

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Photo 7: Phase 1C area with loose panel – dropped 1 ½” to 2”

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