Great care is required by all parties to convert a leaky flat roof into a sloped non-leaking roof
By Chuck Howard, PE
W hen John Martindale, President of Brothers Services Company, Baltimore, Md., wanted to expand his market in the local area, he looked into the commercial metal retrofit market. Having been a very successful and large residential contractor for years, he felt he needed to diversify into this market.
His first step was to attend the 2003 METALCON International convention held in Tampa, Fla. He attended a seminar that described the basics of the metal retrofit roof market. I was fortunate to be presenting this seminar and even more fortunate to meet John after the seminar, which led to an ongoing professional relationship. It was obvious from the start of this relationship he was acutely interested in entering this attractive market in a manner that would make sure Brothers would “do it right the first time.”
While not every step has been totally flawless the first time, his insistence on making the customer’s finished product right the first time has always prevailed. Their most recent finished project, Orleans Court Condominiums, located in Ocean City, Md., is a prime example of this philosophy and is the example to be used to demonstrate how there is really only one way to construct a metal retrofit roof: “Do it right the first time.”
This story starts at the Virginia School Board Convention in November 2006. A school board member, like most do, proclaimed he did not understand why school roofs were designed and constructed with a predominately flat profile. His opinion was that to re-roof a flat roof, without adding pitch and a metal roof, was a travesty and their school board was determined not to allow that to continue. He asked us to contact Blake Giddens at Restoration Engineering, Inc., since his firm provided most of the roof engineering services to their district. That contact yielded no positive information about an upcoming school project, but, instead, an interest in converting a flat roof on a condominium in Ocean City, Md., to a sloped, painted, aluminum roof. Blake indicated he was somewhat aware of the concept of adding slope to a flat roof, but was asking for whatever advise and suggestions we might have in order for him to provide a design that was “right the first time.” Of course he could have prepared a loosely put together specification, generic plan and hoped a contractor would be capable of filling in the design holes, but he, instead, was very receptive to engineering and detailing that was proven effective over time.
REI provided a full set of detailed plans and specifications that accurately depicted his expectation for the metal retrofit roof. Included in his specifications, was the requirement the contractor prepare a set of engineered shop drawings showing how his basic design concept would be satisfied by the contractor’s approach and materials. BSC was fortunate to be selected out of three bidders to construct the metal retrofit roof.
The bid stage was “done right” and yielded a competent contractor, skilled and experienced in metal retrofit roofing. After a proper contract was executed, the contractor began the design process.
Over the years everyone has seen good and bad attempts at providing shop drawings. The “bad” ones use standard details pasted together to yield a patch-work of drawings and details, none of which truly depict the actual conditions of the particular roof. The “good” ones actually measure the existing roof, perform wind design load calculations, perform fastener pull tests from the existing structural components and provide a set of scaled drawings and details that truly describe how the metal retrofit roof is to be applied to the existing flat roof.
The second approach is more time consuming and costly, but was the only way to “do it right the first time.” On this particular project, BSC knew this was the only way to proceed.
First the new roof needed to be properly designed. ASCE-7-05 was used to determine the wind speeds and corresponding wind uplift loads in all specific areas of the new metal roof. That is the critical foundation for any roof project, but, unfortunately, is one often given little importance. A mistake here could have devastating effects in the future. Need I say: “Do it right the first time?”
During the design process, materials needed to be selected. The coastal environment called for an aluminum roof and galvanized steel sub-framing members. An Englert S2500 aluminum panel (.040-inch), with a Kynar-based paint system was selected to be placed on an MBCI, 16 gauge galvanized, sub-framing system. The ASTM E-1592 uplift tests for the Englert panel was obtained to determine where clip supports were necessary, then appropriate framing was designed to adequately transmit the wind design loads into the existing building structure.
Normally a light-gauge banding system would have been utilized to stabilize the new sloped roof structure, but 16 gauge angles were used instead to further add stiffness to the framing system which might have to withstand 120 mph coastal winds. In addition, the owner wished to add a 7-foot roof overhang over the decks of the top units, in order to provide shade. While the structural members were designed to cantilever over this space, exterior columns were added by agreement of the owner, REI, and BSC. This addition, was a little “belts & suspenders,” but assured all involved we would not ever have to worry about the coastal winds disturbing this condition. We didn’t want to come back later, but, rather, “do it right the first time.”
Now, some 14 months after that board member stop at the booth in Virginia, we had located a willing owner with a need, a very capable engineer to create a bid and contract package, a contractor willing to do the work for a set price and a finished design and needed materials selected. All that had to be done now is to put it all together!
The project was started on January 14, 2008 and completed June 20, 2008. An experienced subcontractor was retained to lead the construction activity, with BSC employees working with them to accomplish the needed work.
Critical to this process was BSC’s project manager, Phil Lisak. Although this was his first metal retrofit roof project of this complexity, Phil provided the necessary controls on material procurement and scheduling, as well as monitoring the progress of the work. This vital part of the construction puzzle is often overlooked. It is sometimes assumed a well designed project, with a qualified crew, will always produce a good final product. Unfortunately, metal roof construction is not that simple. Phil proved to be up to the many challenges associated with this job, including one of the most important: motivating the men to perform quality work. That required him to know what the shop drawings were depicting, as well as having the tenacity to make sure things were put where they were supposed to be.
At the same time, the men needed to be motivated to perform the work in an efficient and effective manner. The driving force for him was to get the roof components installed as they were designed and “do it right the first time.” With only a few minor exceptions, that was accomplished.
The majority of roof lawsuits in the metal roofing industry are caused by faulty installations. The main reason a project does not make the margins expected is attributed to faulty installations and a lot of re-work dollars spent. Phil did an excellent job of working with the men to ensure there was no faulty workmanship. And the final results: zero punch-list in late July after a walk-through with Blake Giddens! Great job, Phil.
In summary, there are eight major components that make up a well planned and executed metal retrofit roof project:
1. A building owner that understands the long term benefits of converting a flat roof that leaks into a sloped one that doesn’t.
2. A competent design professional providing a detailed set of bid and contract drawings.
3. An experienced metal roof contractor, with experience in metal retrofit roofing.
4. A set of engineered shop drawings based on ASCE 7-05 wind uplift calculations and ASTM E-1592 metal panel wind uplift testing provided by the contractor. These need to be prepared by a licensed professional engineer with experience in this area.
5. Materials which are appropriate for the specific design.
6. Installers who are well qualified in this type of work and who understand the concept portrayed in the shop drawings.
7. A project manager capable of motivating the work force to produce a quality product in a specified amount of time.
8. Most importantly, doing all of the above “right the first time.”
There you have it. From John Martindale wanting to make sure his company “did it right the first time” by attending METALCON in 2003, to his company insisting the Orleans Court Condominium project was designed and installed “right the first time.”
The metal retrofit roof market provides a great opportunity for companies like BSC that believe in this, but also provides great risks for those that do not. Make sure you are one of the contractors that are successful and “do it right the first time.”
It has been a great privilege to be a part of this success story for Brothers Services Company and, in particular, the Orleans Court Condominiums in Ocean City, MD. Please feel free to contact me at firstname.lastname@example.org with any questions about this project, or other questions concerning the metal retrofit roof market.