Author Archives: CS Editor

Protect the Roof

slaton patterson sutterlinFAILURES
Deborah Slaton, David S. Patterson, AIA, and Jeffrey N. Sutterlin, PE

One of the most critical (but often neglected) components in ensuring ‘watertightness,’ the roof assembly is typically installed early to protect the unfinished building from water penetration, enabling interior work to advance. However, this early sequencing requires the installed roof to withstand construction traffic and potential abuse for the remainder of construction while vertical wall assemblies, mechanical equipment, and other systems are being completed. Additionally, because roof surfaces provide convenient storage areas for building materials and equipment, and support for suspended scaffold or other means of access, completed roof assemblies can be vulnerable to damage from such construction-related activities.

Although the roof membrane is protected from damage from some material and provided with general pathways for workers, sheet metal panels and other construction-related materials are staged away from the pathways without any protection of the single-ply roof membrane. Photos courtesy Jeffrey N. Sutterlin

Although the roof membrane is protected from damage from some material and provided with general pathways for workers, sheet metal panels and other construction-related materials are staged away from the pathways without any protection of the single-ply roof membrane. Photos courtesy Jeffrey N. Sutterlin

Over the past decades, single-ply membranes have increased in popularity for low-slope applications due to perceived advantages in installation, scheduling, energy efficiency, and pricing. In contrast to multi-layered built-up roofs (BURs), single-ply membranes—typically thermoset or thermoplastic polymer—consist of a relatively thin, single layer of waterproofing protection, resulting in an increased susceptibility to damage during construction. Although many single-ply membranes are reinforced to add strength, puncture resistance, and dimensional stability, when membrane damage does occur, it can result in leakage to the underlying roof assembly and building interior.

While the roofing industry generally acknowledges the importance of properly protecting a completed membrane from construction traffic and unintentional abuse, there are few guidelines regarding temporary protection. Instead, the industry appears to rely on the conventional wisdom of competent field personnel. However, common sense does not always prevail.

A hard-wheeled lift is used to access higher reaches of the roof enclosure without benefit of protection of the membrane. Workers are welding over the unprotected membrane—an activity that resulted in holes in the membrane from weld spatter.

A hard-wheeled lift is used to access higher reaches of the roof enclosure without benefit of protection of the membrane. Workers are welding over the unprotected membrane—an activity that resulted in holes in the membrane from weld spatter.

Recommended practices to protect single-ply roof membranes include:

1. Storage of material and equipment on completed roof membranes should be avoided. Where unavoidable, caution should be taken not to overload the assembly or underlying structural system and to provide proper membrane protection. Structural plywood sheathing over high-density rigid insulation has been found to provide low-cost, but effective, protection.

2. If construction traffic is anticipated in certain roof areas or pathways, a temporary walkway or layered protection should be provided.

3. The completed roof membrane should be constantly monitored and cleaned to prevent accumulation of sharp objects and/or debris that could damage the membrane.

4. Materials that may adversely affect the roof membrane should be identified and their proper use (and required membrane protection) understood and closely monitored.

5. On completion of construction activities, the roof should be thoroughly cleaned and inspected, with any damage repaired. Should membrane damage occur, infrared thermography or low/high-voltage scanning equipment can be useful for identifying moisture within the assembly.

6. Specifications and quality control procedures can be strengthened to ensure proper protection of completed roof assemblies.

The opinions expressed in Failures are based on the authors’ experiences and do not necessarily reflect those of the CSI or The Construction Specifier.

Deborah Slaton is an architectural conservator and principal with Wiss, Janney, Elstner Associates (WJE) in Northbrook, Illinois, specializing in historic preservation and materials conservation. She can be reached at dslaton@wje.com.

David S. Patterson, AIA, is an architect and senior principal with the Princeton, New Jersey, office of WJE, specializing in investigation and repair of the building envelope. He can be reached at dpatterson@wje.com.

Jeffrey N. Sutterlin is an architectural engineer and senior associate with the Princeton office of WJE, specializing in investigation and repair of the building envelope. He can be reached at jsutterlin@wje.com.

Getting noise under control

TZ Curtain Wall grinder enclosure

This curtain wall enclosure has reduced noise levels by 20 percent at a western Michigan automobile recycling facility. Photo courtesy Zoneworks by Rite-Hite

by Kyle Justice

Employee safety is an important factor for a Western Michigan automobile parts recycling facility, which is why a wall of insulating curtain was specified to enclose the noisy grinder. The new enclosure has resulted in a 20 percent noise reduction, creating a more comfortable and productive work environment for employees.

At the recycling facility, plastic bumpers were being grinded inside a standalone, 836-m2 (9000-sf) structure called the ‘grind house.’ Noise was an immediate issue and needed to be addressed; the heavy-duty grinder was running virtually non-stop five days a week. A facility employee would continually load the grinder during each eight-hour shift while other employees nearby stripped the bumpers. Grinder noise was greatly amplified by the expansiveness and 5.5-m (18-ft) tall ceilings of the room. To initially protect against grinder noise—which was recorded at 120 decibels (dB)—employees wore both earplugs and earmuffs. Although the ear protection was considered safe, verbal communication between employees inside the facility was virtually impossible during operation.

The company’s initial plan for noise reduction was to build a permanent wall around the grinder. Before starting the project, however, other options for keeping noise to a manageable level were explored.

In the end, a flexible, reconfigurable fabric wall system was specified rather than a permanent wall to enclose the grinder.

Hanging like a curtain, fabric walls can be configured to fit various interior spaces, and be installed faster than permanent walls. Each insulated wall panel was constructed of durable, fire-retardant industrial fabric surrounding multiple layers of recyclable, anti-microbial polyester batting. Individual 1.5-m (5-ft) wide fabric panels of varying lengths were interconnected with fabric connectors to form each continuous wall.

Employees of the automobile parts recycling company installed the sound-dampening assembly around the grinder, which sits against a back wall in one corner of the facility. Two of the fabric curtains run the length of the grinder from front to back. They are attached to a concrete wall at the back of the grinder with screws and polyester nailing flaps. At the front-end of the grinder, connectors secure the front of the enclosure to the two sides. The front wall also has an opening where bumpers are fed into the machine. The connectors tightly seal the cut-out that serves as the grinder opening.

At the top of each wall, the fabric curtain walls are attached to angle iron previously built above all three sides of the grinder. The curtain’s weight holds the bottom in place on all sides. Inside the enclosure, a 254-mm (10-in.) diameter metal conduit routes the plastic chips from the side of the grinder to a hopper located outside the building.

Although new to the installation of fabric walls, three grind house employees installed the flexible enclosure in a little more than three days. To check the grinder for maintenance, employees simply pull back a part of the wall where it is attached with fabric connectors to gain access.

With the fabric walls in place, the grinder is completely enclosed. Subsequent tests showed the sound level inside the grind house dropped from 120 dB to 96 dB, representing a 20 percent reduction in noise.

With grinder noise under control, employees working in the facility only need to wear earplugs and can more easily communicate with each other. Above all, the insulated fabric wall system creates a safer environment for employees.

Kyle JusticeKyle Justice is product manager for Rite-Hite Environmental Enclosures. He has been in the warehousing and manufacturing industries for more than 15 years and has extensive knowledge of product flow, storage, and manufacturing processes across a broad spectrum of industries. Justice can be contacted at kjustice@ritehite.com.

New natural stone selection app available

Marble Institute of America (MIA) has released Stones of North America Version 3, providing design and construction professionals with access to detailed information about stones quarried in North America. The free, comprehensive iPad app includes 31 new natural stones from more than 100 quarries, programming updates, and companion websites providing additional information. Architects, builders, and design professionals can search for natural stones by type, color, intended use, and distance from the project. For each type, technical specifications, physical properties, and other details are available.

ConsensusDocs publishes commissioning contract

A new contract for projects using commissioning services is now available through ConsensusDocs Coalition. ConsensusDocs 820, Owner and Commissioning Authority Agreement, provides language for owners to employ when procuring commissioning services verify building system performance. Additionally, the contract establishes rights and obligations for the individual serving as the commission authority. It was developed with the help of AABC Commissioning Group (ACG), an association of certified commissioning authorities, along with input from American Society for Healthcare Engineers (ASHE) members. Visit www.consensusdocs.org for more information.

Builder’s hardware certification video released

A video and two new infographics have been released by Builders Hardware Manufacturers Association (BHMA) to illustrate the organization’s certification process. The certification applies to locks, closers, exit devices, and other types of builder’s hardware with the goal of creating safer facilities. The four-minute video is aimed at architects, specifiers, or building owners, and provides a concise visualization of how hardware is certified. Commonly asked questions are answered about applications, lab testing, and audits with simple terminology. The infographics—“Steps to Certification” and “Is It a BHMA-certified Product?”—helps viewers identify hardware that meets the association’s requirements. The video and infographics are available for download at www.buildershardware.com.