Projects
Notre Dame Projects
Navy Pier Roofs
Siemens follows Bayer and Hires Local Firm, Again
Niles Warehouse
ConSpecT Services, Inc. was awarded a contract by the University of Notre Dame in 2004 to perform Quality Assurance Monitoring services for the Hesburgh Library reroofing project. The Hesburgh Library is the 17 story building just north of the football stadium. The size of the project on the seventeenth floor roof was only 8,000 sq. ft. but was 84,000 sq. ft. on the third floor roof.
Since then, ConSpecT has performed various services such as roof condition assessments, reroof design, plans, specifications, bid documents, quality assurance monitoring services, and roof consultations for numerous other buildings on campus including:
- Fitzpatrick Hall of Engineering
- Galvin, Friemann, Lobund
- Galvin Life Science Hanks Wing Addition
- Haggar Hall
- Hesburgh Center for International Studies
- Hessert Aerospace Research Center
- Mason Services Support Office Complex
- Mendoza College of Business
- Notre Dame Football Stadium Perimeter Roofs
- Rockne Memorial Building
- South Dinning Hall
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The Chicago Metropolitan Pier & Exposition Authority selected ConSpecT to perform its 2004 roof condition survey. The pier is over a ½ mile long and has over 52 different roof systems. Some of the roof systems are unique such as the copper dome over the Ballroom & Towers, the mechanically attached PVC system over the Festival Hall convention facility, and the Shakespeare Theater tensioned fabric roof. The masonry walls at or above roof level were also surveyed for condition deficiencies.
ConSpecT was selected for their Roof Value Assurance program that assists building managers and facility engineers in maximizing the return on their investment in roofing assets. After the initial roof condition survey, an 89-page report was issued with commentary on all of the systems, digital images of all of the anomalies found, descriptions of each deficiency, and repair recommendations. The Executive Summary prioritized maintenance needed, recommended courses of action, and cost estimates of the more urgent priorities.
Since then ConSpecT has provided additional consultation services for reroofing projects in 2006, 2007, and 2009.
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Siemens follows Bayer and Hires Local Firm, Again
Bayer Corporation originally contracted with ConSpecT Services, Inc. circa 1998 to provide Roof Condition Assessments on most of their roofs at their main campus on Miles Avenue in Elkhart, Indiana. In 1999 Bayer contracted ConSpecT to provide reroof design, plans, specifications, bid document preparation services for their Bayer HealthCare, LLC plant in Mishawaka, Indiana. The entire building was reroofed which included 4.2 acres of reroof construction.
Bayer HealthCare, LLC turned to ConSpecT again in 2003, to provide roof consulting services for several more of their Elkhart facilities for everything from the initial condition evaluations and infrared surveys to drafting new plans, flashing details, specifications, and performing quality assurance monitoring of the roofing contractors work. There were four separate contracts in all, with the entire project completion before winter.
Since then Siemens Corporation has purchased one of the plants in Elkhart and has followed Bayer’s reroof success experience by hiring ConSpecT to provide reroof, design, plans, specifications, bid documents, and quality assurance monitoring during reroof construction of additional sectors in 2008 and 2009.
Case Study - Extending Service Life of a Failing Roof Since 2001 to Date.
EXISTING SYSTEM BACKGROUND:
It is ConSpecT’s understanding that the existing membrane is a Tremco® 3-ply Built-Up Roof with modified asphalt, installed over a base sheet nailed directly to the gypsum deck. There is no roof insulation on the gypsum deck. The insulating value is from the fiberglass formboard and the rest of the roof assembly.
Commentary of Pre-Alteration Existing Conditions:
Except for the valley areas between drain castings, the overall roof surface drains fairly well considering the extremely low slope. However, most of the drain valleys (areas between the drains) did not have any slope and in many cases negative slope. To compound the problem, many of the drain castings are set too high (no sump). Also, the multiple layers of flashing material around the drain flashing area blocks drainage to the drain casting inlet ports and the rim of the drain was approximately ½" high. Even in areas that were perfectly dead level, the water would pond ½" deep before any water goes into the drain.
In addition, there are random low spots in the gypsum deck. Many of these low spots are located in the no slope areas between or around the drains. The result is expansive ponded areas. Where the drain is set too high, the problem is compounded.
Consequently, there are numerous large ponded areas between the drains that do not drain (See Digital Images). Depending on the weather and ambient air conditions water sometimes sets in the deeper ponded areas for a week or more at a time until it evaporates. In the past water had leaked into the building, primarily at the areas around the drains. Only a few isolated cases of leaks have occurred away from the drain area locations.
It appears that when this existing built-up roof membrane was installed, the felt runs were from a line mid way between drains to a line mid way between the next drain. The length of the ply felts were generally started and ended at the midpoint between drains and the plies were overlapped with the pervious area and then covered with a stripping ply installed over and perpendicular to the direction of the field plies. This doubling of the plies, heavier moppings of asphalt, and the perpendicular cover ply felt leaves a high area between many of the drains that restricts flow and isolates ponded areas. Since there is practically no slope between the drains, this hump created by the doubling of the felts sometimes divides ponded areas into two isolated areas.
Flashing Conditions:
The adhesion around the edge of the Hypalon® drain sump flashing is failing at many locations. Layers of repair materials over these flashing areas have caused a "hump" or damn around the drain inhibiting drainage. When leaking occurs in areas that pond water, the volume of water leaking into the building is substantial and lasts for long periods of a time. In addition, some of the plumbing drain line connections to the roof drain castings appear to be leaking which makes it difficult to determine if the leaks are coming from the adjacent roof membrane, the edges of the drain flashing, or leaks in the plumbing drain line connections.
Other Challenges:
Some of the lap joints on the Hypalon® base flashing along the parapet walls are coming loose. Past repairs at some locations have been made with asphalt mastic cement, which has hardened, shrunk, and are now cracking open.
There are a few isolated locations of repairs to splits in the built-up roof membrane. Most of these repairs are holding for now but these areas must be inspected and maintenance performed.
Findings at Specific Locations:
Core-cut samples and Delmhorst® electric probe readings were taken at areas shown as “Possible Damage” on the infrared report, at other suspected areas, and one core-cut at an up-slope (presumably dry) area to use as a standard. Delmhorst® readings are not a representation of percent of moisture in a sample material. They are instead a reading of electrical conductivity that increases as moisture increases in a sample. This reading can be extrapolated to represent approximate ratio of moisture if necessary. Readings taken on the core samples extracted from this roof were as follows:
- Core #1 next to Drain #26 an area marked as “Possible Damage” on the infrared survey had a Delmhorst® reading of 62 to 64.
- Core #2 at an up-slope area that had reportedly leaked substantially within the last year also had a Delmhorst® reading of 0.
- Core #3 at a dry up-sloped area had a Delmhorst® reading of 0.
- Core #4 next to Drain #17 an area that appeared to be an area that may be wet had a Delmhorst® reading of 0.
- Core #5 next to Drain #46 an area that was reportedly leaking had a Delmhorst® reading of 0.
- Core #6 next to Drain #9 an area marked as “Possible Damage” on the infrared survey, had a Delmhorst® reading of 0.
- Core #7 next to Drain #17 an area that appeared to be wet had a Delmhorst® reading of 0.
- Probe Area #8 was through a ridge in the Hypalon® flashing around Drain #33 and had a Delmhorst® reading of 85. Moisture could be squeezed out of the probe holes so it was not a false reading. The moisture was trapped between the Hypalon® and the membrane plies.
- Probe Area #9 and #10 at Drain #1 and #2 had a reading of 0.
CONCLUSIONS OF EXISTING CONDITIONS
On roofs with less than 1/16" per foot slope, very minor irregularities in the finished gypsum surface uniformity results in restricting the flow and producing ponding. In areas with positive slopes these irregularities and resulting minor ponding do not appear to be creating any serious problems.
The major problem on this roof sector is lack of positive slope (and in many cases negative slope) between drains. The low areas between the drains are probably due to deflection in the structural members between the drains which then increases ponding and consequently increases weight, which then again increases deflection. Many of the high drains are likely a result of locating the drain too near the columns and away from the deflection.
All of these factors plus those mentioned in the “Commentary” section above, compound to create the ponding we are now seeing on this roof. The Tremco® design manual specifically states that “All roofs should have positive drainage.” The majority of these problems should have been corrected in the design of the last reroofing program. Unless the owners of the building at the time of reroof design specifically instructed otherwise or agreed specifically to accept the existing negative slope condition, the fact that the drainage was not corrected should be considered a reroofing design error by the reroof designer.
Previous post reroof attempts to sump (lower) the drain casting have not worked due to the build-up of roofing plies around the drain to flash in the retrofit. Lowering the drain casting without reroofing is a difficult procedure (See Digital Images 22, 63, 113).
We did not have the opportunity to review the original structural drawings for verification of how the slope that does exist in the deck perpendicular to the valleys was created. However, we have come to the conclusion that the deck is most likely structurally sloped because the gypsum was approximately 2" thick at all full depth core cuts.
EXISTING CONDITION EVALUATIONS
As shown in the infrared survey and verified by the core-cut samples and electrical probes, there are very little widespread areas of moisture entrapped in the roof assembly or the gypsum deck. The gypsum deck in the areas that are shown as wet, are not wet to the extent that roof repairs cannot be performed. This statement is based on evaluation of core cut samples and the Delmhorst® electric probe readings.
The most logical explanation for the Core #2 reading at the up-slope area that had reportedly leaked substantially within the last year, is the downward drying capabilities of the fiberglass form board under the gypsum deck. This area had had so much water leaking through it in the past that the gypsum was weak and crumbly yet it had completely dried out within a year. During future reroofing or repair projects, there may be a need to replace minor amounts of gypsum deck areas due to structural inadequacies from gypsum deterioration. However, if the gypsum is dry enough to hold the mechanical fasteners; it appears that the wetness will dry out after the leaks are stopped
