Project Profiles: Historic Preservation

CATHEDRAL OF ST. PAUL, BIRMINGHAM, ALA.

Team

ROOFING CONTRACTOR: Midland Engineering Co., South
Bend, Ind.
ARCHITECT: ArchitectureWorks LLP, Birmingham
GENERAL CONTRACTOR: Hoar Construction LLC, Birmingham,
MASONRY CONTRACTOR: Ziolkowski Construction Inc., South Bend

The cathedral’s intricate slate tile patterns incorporated three slate colors and square and deep bevel cut tiles.

The cathedral’s intricate slate tile patterns incorporated three slate colors and square and deep bevel cut tiles.

Roof Materials

The Catholic Archdiocese of Birmingham required the cathedral’s new roof system be a historically accurate reproduction of the original in materials, design and craftsmanship. The cathedral’s intricate slate tile patterns incorporated three slate colors and square and deep bevel cut tiles. Six large slate crosses and multiple accent patterns, barely visible on the faded original roof, required exacting measurements prior to tear-off and a high level of precision to recreate and maintain over such a large field and on octagonal steeples.

Because of metal thinning brought on by their advanced age, every copper architectural and functional feature in the existing roof system had to be carefully removed and shipped to Midland Engineering’s South Bend facility to be historically replicated in its metal shop. This included seven ornate crosses (up to 17-feet tall), finials, turret caps and more. There were more than four dozen components, for which no original prints existed, as well as over 500 feet each of custom copper cornices and radius gutters with matching straps. More than 20,000 square feet of 16- and 20-ounce copper was utilized for fabrication of architectural elements and flashing.

Midland Engineering was asked to make improvements to the original roof system to improve attic ventilation while maintaining the Gothic Revival period look. To accomplish this, the crew integrated bronze screen (invisible from the ground) into the original copper cornice and eave design to provide improved cold air intake while new louvered copper dormers replaced the original painted roof ventilator.

An updated lightning protection system was incorporated into the new roof design, hidden within many of the new copper crosses and other architectural elements. The system was fabricated in Midland Engineering’s shop to maintain the Gothic Revival look.

The metal shop also clad 10 previously painted windows and mullions in copper, effectively eliminating frequent and costly maintenance. These windows, reachable only by crane at considerable expense, formerly required painting and other maintenance every five to seven years.

About 6,500 square feet of lead-coated copper, which patinas to a limestone color, was utilized to cap all limestone exposed to weather, reducing ongoing maintenance of limestone joints.

Extensive termite damage to structural framing required repair prior to installation of the new roofing system. Upon removal of the original slate roof and completion of the structural repairs, the new roof was dried-in and installation of the new slate roof began. The historically accurate replacements of the original copper architectural features were installed according to schedule.

SLATE SUPPLIER: North Country Slate
COPPER SUPPLIER: Hussey Copper

Roof Report

The Cathedral of St. Paul is the centerpiece of the Roman Catholic Diocese of Birmingham. Completed in 1893 at a cost of $90,000, the cathedral is widely considered to be a handsome example of the American Neo-Gothic variant of the Gothic Revival style. The cathedral measures 96-feet wide by 140-feet long and encompasses more than 60,000 square feet. It features twin octagonal steeples, rising 183-feet high.

Work schedules on this project were a challenge. The contract required parishioner and clergy access to the church must be maintained 24 hours a day, seven days a week, throughout the eight-month duration of the project. Further, because of the noise inherent in roof construction, work schedules had to be planned around regular church services and events and rescheduled several times a month for funerals and other unscheduled events.

“We could not have been more pleased with the work accomplished by the team from Midland Engineering,” says Very Rev. Kevin M. Bazzel, V.G., J.C.L., rector of the Cathedral of St. Paul. “It is a marvel to us to be able to see the church in its original glory, and all of this thanks to Midland!”

The National Roofing Contractors Association, Rosemont, Ill., awarded Midland Engineering the prestigious Gold Circle Award in 2016. Midland was recognized in the Outstanding Workmanship—Steep-slope Category.

Photo: Rob Culpepper

Pages: 1 2 3 4

RCI Announces Speakers for October Building Envelope Technology Symposium

Raleigh, N.C.-based RCI Inc. has assembled a panel of expert speakers to discuss methods for designing sound building exteriors. More than 300 building designers and construction professionals are expected to be in attendance at the association’s annual Building Envelope Technology Symposium, which will be held Oct. 17-18 at the Westin Galleria Houston, Texas.

The program features 12 educational sessions presented by leading building envelope designers. Speakers offer their experience-based insight for specification of sound, durable exterior enve- lopes. Most programs focus on repair and/or sustainable design methods for strengthening and improving existing structures.

Attendees can earn up to 12 continuing-education credits from RCI and the American Institute of Architects, Washington, D.C. An evening reception after the close of the first day’s meeting will allow those in attendance to network and mingle with fellow professionals.

This year’s topics and speakers include:

The Performance of Weather-Resistant Barriers in Stucco Assemblies
Karim P. Allana, RRC, RWC, P.E. | Allana Buick & Bers Inc., Palo Alto, Calif.

Aluminum Windowsill Anchors and Supplemental Waterproof Flashing Design Practices
Rocco Romero, AIA | Wiss, Janney, Elstner Associates Inc., Seattle

The Ideal Third-party Warranty: A Risk-managed Approach
Lorne Ricketts, P.Eng. | RDH Building Science Inc., Vancouver

Playing Against a Stacked Deck: Restoration of a Stone Fin Façade
Matthew C. Farmer, P.E. | Wiss, Janney, Elstner Associates, Fairfax, Va.

Everyone Loves a Pool, But What’s Lurking Beneath the Surface?
Rob Holmer, P.E., GE | Terracon Consulting Engineers, Sacramento, Calif.
Michael Phifer | Terracon Consulting Engineers, Sacramento

Design Principles for Tower and Steeple Restoration
Robert L. Fulmer | Fulmer Associates Building Exterior Consultants LLC, North Conway, N.H.

When the Numbers Don’t Work: Engineering Judgement Tips for Historical Buildings
Rachel L. Will, P.E. | Wiss, Janney, Elstner Associates, Chicago
Edward A. Gerns, RA, LEED AP | Wiss, Janney, Elstner Associates, Chicago

Air Barrier Integration: Don’t Entangle Yourself with These Common Pitfalls
Timothy A. Mills, P.E., LEED AP, CIT | TAM Consultants Inc., Williamsburg, Va.

Upgrading the Performance of Heritage Windows to Suit Modern Design Conditions
Scott Tomlinson, P.Eng. | Morrison Hershfield, Ottawa, Ontario, Canada

Design Considerations for Renewing Podium Waterproofing
Bereket Alazar, RRO, LEED AP BD+C | Morrison Hershfield, Edmonton, Alberta, Canada
Stéphane P. Hoffman, P.E. | Morrison Hershfield, Seattle

Fully Soldered Metal Roofing: More Complicated Than You Think
Nicholas T. Floyd, P.E., LEED AP | Simpson Gumpertz & Heger Inc., Waltham, Mass.

A Case History of ETFE on Today’s Projects
Lee Durston | Morrison Hershfield, St. Paul, Minn.
Shawn Robinson | Morrison Hershfield, Atlanta

For more information, visit RCI’s website, or call (800) 828-1902.

Restore Domes with 22-karat Gold Restoration Film

RealGold Inc. announces a new, cost-effective 20-plus-year 22-Karat Gold Dome Restoration Film.

RealGold Inc. announces a new, cost-effective 20-plus-year 22-Karat Gold Dome Restoration Film.

RealGold Inc., a manufacturer of genuine gold and silver exterior-grade products, announces a new, cost-effective 20-plus-year 22-Karat Gold Dome Restoration Film.

Used to beautify church domes throughout the U.S., Europe and Asia, the 22-karat gold film features a 20-plus-year outdoor warranty. Guaranteed non-fading and non-delaminating for 20 years, the maintenance-free exterior grade of the gold film is durable and features a non-stick surface resistant to airborne contaminants and fowl waste.

The 22-Karat Gold Dome Restoration Film features a permanent self-adhesive application process, costing a fraction of traditional hand-applied gold leaf. It far outlasts gold-colored paints, which are prone to fading and peeling.

For a free estimate of RealGold’s 22-Karat Gold Dome Restoration Film, interested parties are invited to email the height and base diameter measurements of the dome, along with photographs of the dome highlighting two sides, to billcrowley@realgoldinc.com.

With Today’s ‘New Age’ Roofs, Removing All System Components May Not Always Be Required or in the Clients’ Best Interest

Years ago, reroofing design involved removing all roof-system components down to the roof deck and rebuilding a new roof system up from there.

PHOTO 1: This EPDM roof’s service has been extended for nine years and counting, approaching 30 years in-situ performance. Here, the restoration of perimeter gravel- stop flashing and lap seams, as well as detailing of roof drains, penetrations and roof curbs, is nearing completion.

PHOTO 1: This EPDM roof’s service has been extended for nine years and counting, approaching 30 years in-situ performance. Here, the restoration of perimeter gravel- stop flashing and lap seams, as well as detailing of roof drains, penetrations and roof curbs, is nearing completion.

Although that is still a viable option and often performed, the coming of age of many single-membrane roofs has altered the method of installing a new reroof system. Options now include EPDM roof restoration; removal of the roof membrane and the addition of new insulation and roof membrane; using the existing roof membrane as a vapor retarder and adding new insulation and roof membrane; removal of the roof cover and installation of new, leaving all the existing insulation in place.

When I first moved into roof-system replacement design some 35 years ago, the dominant roof systems being removed were bituminous, specifically gravel-surfaced asphaltic and coal- tar-pitch built-up roofs. As they aged, their surfaces often started to blister, crack and undulate with ridges—surfaces often unsuitable for roof recover. The bitumen often was deteriorating because of ultraviolet-light exposure; when that occurred, the deterioration of the felts was not far behind. The insulation was mostly perlite or high-density wood fiber; the amount was minimal (low thermal value) and, more often than not, flat or with very minimal slope. Drains were erratically placed, tapered insulation was not often the case and roof edges were predominately gravel stops. In the Midwest, many roof decks were cementitious wood fiber. The roof covers were often patched again and again, even as water infiltrated the system.

PHOTO 2: The re-flashing of roof curbs is an integral part of the restoration of EPDM roof membranes.

PHOTO 2: The re-flashing of roof curbs is an integral part of the restoration of EPDM roof membranes.

When replacement was necessary, the roof-edge sheet metal was removed; the entire existing roof system was removed down to the roof deck; and a new roof system was designed, often incorporating vapor retarders/temporary roofs so the removal of multiple layers of roofing could be accomplished, roof curbs raised, and enhancements of roof drains, curbs and roof edge could occur prior to the installation of the new roof cover. Tapered insulation designs be- came common; this would often require realignment of the roof drains to simplify the tapered design and installation. To accommodate the new insulation thickness, the roof edge had to be raised as did roof curbs, RTU curbs, plumbing vents and roof drains via extensions. Roof membranes changed from bituminous to those classified as “single plies”: EPDM, PVC, CPE, CSPE.

These new roof-system replacement designs resulted in superior roofs—85 percent of all the reroofs I have designed are still in place, still performing, still saving the owner money. Life cycles have moved from eight to 12 years, up to 18 to 25 years and longer. They certainly were more expensive than the original installation and, if a roof designer didn’t have a handle on costs to provide the owner with estimated costs of construction, were often shocking. But these roof systems were good for the client, economy, environment and public.

PHOTO 3: When restoring EPDM roof membranes, the removal of roof penetration flashings and installation of new with target patches will provide another 20 years of watertight protection.

PHOTO 3: When restoring EPDM roof membranes, the removal of roof penetration flashings and installation of new with target patches will provide another 20 years of watertight protection.

Over the years, codes and standards have changed, especially in the past decade, requiring increased insulation values and roof-edge sheet-metal compliance with greater attention to wind-uplift resistance. As the new millennium arrived, these “new age” roofs came of age and owners started to look at their replacement—often with increased costs stifling their budgets.

LEAN THINKING

A factor that increased the performance of many roof systems in the past 20 years was the emergence and growth of the professional roof consultant, often degreed in architecture or engineering, educated in roofing, tested and certified. These professionals brought a scientific approach to roof-system design. Raleigh, N.C.-based RCI Inc. (formerly Roof Consultants Institute) was the conduit for this increased level of knowledge, professionalism and the growth in quality roof-system design and installation.

PHOTO 4: On this roof, the existing loose-laid membrane was removed, open insulation joints filled with spray-foam insulation and new insulation added to meet current code requirements. A new 90-mil EPDM membrane was installed and existing ballast moved onto it to 10-pounds-per-square-foot coverage.

PHOTO 4: On this roof, the existing loose-laid membrane was removed, open insulation joints filled with spray-foam insulation and new insulation added to meet current code requirements. A new 90-mil EPDM membrane was installed and existing ballast moved onto it to 10-pounds-per-square-foot coverage.

As these professionals started to examine the older “new age” roofs, those whose first responsibility was doing what was best for the client saw greater opportunity than just a costly full-roof replacement. Although many roofs today still need to be fully removed, prudent professionals see other opportunities, such as the following:

ROOF RESTORATION
EPDM membrane ages with little change in physical characteristics as opposed to its built-up roofing predecessor; therefore, EPDM membranes often can be “restored” in lieu of removing and replacing the roof. (Studies to support the lack of change in EPDM’s physical characteristics while it ages include Gish, 1992; Trial, 2004; and ERA, 2010.)

Pages: 1 2

Western Colloid Announces Territory Sales Manager

Western Colloid has announced the addition of Rick Boyce as territory sales manager for Texas and the Midwest.

Rick brings with him extensive experience in roofing with more than 40 years in contracting and manufacturing. “His knowledge of different types of roofing systems as well as the installation and restoration challenges that can come up on a roofing project make him the perfect addition to the Western Colloid team.” says Greg Hlavaty, general manager. “Rick brings skills that are very important to Western Colloid, such as the ability to provide solutions for the contractor.”

Rick will be responsible for promoting Western Colloid products, helping establish a distribution center in the Dallas/Fort Worth area, and developing relationships with contractors, specifiers and building owners throughout the region.

“Although we have been previously seen as a western states-based manufacturer, the last few years have shown increased demand throughout the U.S. An expansion into Texas is a natural next step for us.” says Hlavaty. “We feel very fortunate that Rick agreed to be part of our team and we look forward to building our business in the state of Texas.”

Built-in Gutters Should Be Carefully Inspected, Restored and Maintained

Sheet-metal gutter linings, whether made of copper, lead or both, are relatively involved and require the services of a highly skilled artisan craftsman.

Sheet-metal gutter linings, whether made of copper, lead or both, are relatively involved and require the services of a highly skilled artisan craftsman.

Built-in gutters may be the most complicated system in the building envelope, yet they are also the most elusive when you start searching for information about them. Sometimes called Yankee gutters, box gutters or even Philadelphia gutters, it’s no wonder they remain a mystery to many. Built-in gutter systems are actually built into the cornice structure and drain through internal or external leaders. They are not readily visible from the ground, further lending to the mystery of their design and function. Because they are integrated into the structure, built-in gutter linings that fail will cause extensive damage to the cornice and sometimes also the interior of the structure.

In “Traditional Rainwater Conductor Systems of the 18th and 19th Centuries,” Karen Dodge of the U.S. National Park Service, Washington, D.C., states built-in gutters were first adopted in North America during the 18th century in high-style Georgian and Federal-style buildings, usually institutional or commercial, where refined architectural qualities were desired. Although built-in gutters are highly functional, they also serve an aesthetic purpose. As structures were erected in the classical order with elaborate cornices and entablature, it became necessary to collect and channel rainwater without detracting from the architectural character of the building. Built-in gutters served this function well, hidden from sight and shedding water to the exterior.

Built-in gutters, today, are typically constructed in the same manner as they have been since the 18th century. They are wooden boxes with bottoms sloped toward the outlets where water is drained to leaders, or conductor pipes, that channel the water away from the building. The first gutters in this style were actually troughs or box gutters, carved out of wood and rubbed with linseed oil or painted to protect the wood. Corners and seams were bonded with lead wedges. Needless to say, maintenance was critical to their success or failure. Later, the advent of sheet lead allowed for broader gutters, as linings covered the wooden troughs. By the end of the century, copper became available in the U.S. and a popular choice for gutter linings because of its durability and the functional nature of the material in a sheet-metal application.

INSPECTION AND MAINTENANCE

The most common sign of water penetration is peeling paint and decay in the wood soffit under the gutter. Other signs are dark stains and mildew or deterioration of masonry. Water infiltration may be visible in attic spaces or areas beneath the gutters where plaster and other interior finishes evidence water damage. The sooner a leak or area vulnerable to failure is addressed, the smaller the scope and cost of repairs. Cleaning out leaves and debris from gutters as often as necessary is essential for durability and proper performance.

Careful inspection by a competent roofer is critical to the longevity and success of the system. He or she will look for defects, such as localized damage caused by fallen limbs or other debris, cracks from expansion and contraction at joints or folds, or pinholes from corrosion. Roofing tar and other bituminous compounds should never be used to patch, repair or coat gutter linings. It makes the condition of the gutter indeterminable, corrodes metal linings, will crack and fail quickly, and cannot be removed without destroying the lining. Ice damming is not uncommon in the winter but should not be removed with sharp tools for obvious reasons.

When tin or terne-coated steel gutter linings fail, water intrusion will occur and cause wood rot. Eventually, architectural details will be lost and replacement will be necessary.

When tin or terne-coated steel gutter linings fail, water intrusion will occur and cause wood rot. Eventually, architectural details will be lost and replacement will be necessary.

RESTORATION

Restoration of long-neglected built-in gutter systems that leak and have caused decay in the cornice and roof structure is often complicated and can be costly. But once the work is completed, a regularly maintained, well-detailed system can last 60 to 100 years or more, depending on the life of the metal lining. A preservation architect or consultant should inspect the building, propose treatment options, develop working drawings and specifications, and supervise bidding and construction. Temporary protection and permanent repairs should be performed by a roofer experienced in this specialty on historic buildings.

“We encourage restoration of historic built-in gutter systems,” says Michael Devonshire, a building conservator and principal at Jan Hird Pokorny Associates, New York. “The use of modern building materials as an adjunct to traditional materials boosts longevity.” Devonshire states the typical steps involved with a built-in gutter restoration involve:

  • Removing the gutter lining and 2 feet of the roof covering above the curbing of the gutter.
  • Repairs to rotted or otherwise deteriorated frame work. Where rafter ends or lookouts are rotted, install sisters (new rafter ends adjacent to old ones) or scarf in new wood and sisters.
  • Replacing the old wooden gutter bottom with a sustainable wood material, such as cedar or kilndried- after-treatment (KDAT) plywood. KDAT is treated for resistance to decay, minimal expansion and contraction, and increased longevity.
  • Installing the gutter lining: an elastomeric ice-and-water shield on the bottom (not always required); building felt; a slip-sheet of rosin paper; and copper on top (16 or 20 ounce, depending on the dimensions of the gutter).
  • Installing the roof covering on the roof deck above the gutter. This includes 2 feet of elastomeric ice-and-water shield (or copper flashing) beneath.
  • Repairing or replacing cornice mouldings, brackets and other architectural woodwork.

PHOTOS: WARD HAMILTON

Pages: 1 2