“Isn’t there someway that we can pitch our old school roofs to eliminate the leaking problems? We have been told that it is too expensive to slope our flat roofs, but we know that we have a continuous expense to maintain our flat roofs. Can you help us?” Over the past 20 years I have heard this plea from frustrated school officials. The answers are simple. Yes, you can convert your flat roofs to sloped roofs. No, it not too expensive. And, yes, there is help to accomplish this much wanted remedy.
The Problem: Flat Roofs
Every school system in the United States has had problem flat roofs. By far the majority of the school structures built for the “baby boomer” generation in the 50’s and 60’s utilize a flat roof construction. This type of construction holds water on the surface of the roof, requiring the top membrane to be completely impervious to the infiltration of water through its surface. Whenever this membrane wears out, splits, or is punctured the infiltration process starts. As anyone with a flat roof will testify, once this infiltration process starts, the integrity of the roof membrane, especially with a flat roof, rapidly decreases. It can therefore be adequately defined that the problem with flat school roofs are that they are: 1) flat and 2) constructed from a membrane that is vulnerable to the elements. A study performed by the Ohio Department of Education indicated that over 20 percent of the local school’s budgets associated with buildings and grounds were spent on roof repair, maintenance, and replacement. This category accounted for the highest percentage of all categories surveyed. Similar studies have shown that this situation exists throughout the school systems of the United States. It cannot be appreciably improved while the majority of our school roofs remain flat.
The Solution: Metal Retrofit Roofs
With the problem being that school roofs are flat, it is obvious that the solution to this problem is to pitch the old flat roofs. To make this process even more successful, the use of metal standing seam roofs on these sloped surfaces allows them to last many times longer than other common roofing materials.
Life cycle costing indicates that the least expensive roof system that can be used is a sloped metal standing seam system. A study done by American Iron and Steel Institute (AISI) indicated that a sloped standing seam metal roof system was the lowest cost roofing system out of eight surveyed, over a twenty year period.
In the school market, almost all of the structures are expected to last considerably more than twenty years. The conclusion is that the sloped standing seam metal roof is the least expensive alternative for schools today.
There are many different systems available today to turn flat roofs into pitched metal roofs. The good news, therefore, is that there is a solution available to the frustrated school official who has been paying for leaking flat roofs.
Metal Retrofit Roofs–Three (3) Steps to Success
Converting flat roofs to sloped metal roofs involves three (3) basic steps. They are as follows:
1. Analyze the existing roof – Analyze the condition of the existing roof. If minor flashing and/or membrane repair will not yield long term results, a slope conversion process is in order. If the existing structure appears to be adequately supporting the existing flat and ponded roof, it should be adequate to support the new sloped metal roof system and associated framing. While this preliminary assumption will need to be verified by a licensed professional engineer, the original structure is normally capable of the increased dead loads (approximately 2.25 psf).
2. Add slope to the flat roof – The slope conversion process is accomplished by installing a light gage steel sub-framing system. This system is designed to collect the required design loads and transfer them to the existing structure. Again, this analysis needs to be performed by a licensed professional engineer in order to insure that the new composite structure can resist the design loads. The composite structure consists of the existing roof structure plus the new retrofit framing system. It is critical that the two (2) systems perform as one system after the conversion process is complete.
3. Install a metal standing seam roof system – After slope has been created for the roof component of the building envelope, install a structural standing seam roof system, utilizing a concealed fastener system to attach the roof panels to the sub-framing. The roof panels should be at least 24 gage steel panels utilizing a GALVALUME® substrate. This coating system has been in the roofing market since 1972 and actual field tests show it lasting well beyond its warranted life of 20 years. In addition, factory coil-coated paints can be applied over the Galvalume® substrate to add color to the new roof. These coating systems, also, have been performing in field conditions well beyond their normal warranted life of 20 years.
In conjunction with the three (3) step metal retrofit roofing process, several other elements of the existing flat roof can be positively altered. First, unfaced blanket insulation can be installed on top of the existing roof membrane prior to the installation of the new metal roof membrane. This insulation can dramatically alter the energy consumption of the building by providing a much warmer “hat” for that building. Next, the cavity created between the old roof and the new roof will be ventilated. This ventilation process will allow the existing roof membrane to dry without, in most cases, the costly and risky process of removing this roof while the building is being occupied. In addition, ventilation of the cavity will not allow heat build-up in the summer and condensation in the winter. Working together, this better insulated and ventilated cavity will greatly reduce heat gain and/or loss through the roof. This benefit, alone, many times allows the metal retrofit roof system to pay for itself within 10 to 15 years.
The Source for Help
Now that you have determined that the cost and problems associated with maintaining a flat roof are outweighed by the benefits of converting it to a sloped metal roof, where do you get help? If there are not readily identifiable metal roof retrofit contractors in your area, contact a reputable metal roof manufacturing firm for names of contractors that have experience in this type of roof system. Make sure that the manufacturer supports a contractor base that is required to be trained by the manufacturer prior to weathertightness warranties being issued. Once a local contractor(s) is located, ask him to meet with you and see your roof. He will, at little or no cost to you, let you know how a metal retrofit roof can be installed over your existing flat roof, and the costs associated with such a project. This will allow you to make budgeting decisions and arrange for necessary funding. Since most school capital projects require public bidding, a design professional will need to be hired to produce plans, specifications, and bid documents. Ask the contractor for a list of local architects and/or engineers that are familiar with metal retrofit roofing. This process of involving the contractor prior to hiring a design professional will allow you to make basic financial decisions before committing to design costs.
Metal Retrofit Roofs; The Educated Choice
The use of metal retrofit roofs allows school districts to end their prolonged costs and aggravations associated with flat roofs. It allows the flat-roofed buildings to undergo a transformation into a sloped-roof building. These new roofs can be either low sloped “functional” roofs or high pitched “architectural” roofs, depending on the expectations of the owner. Both, however, eliminate the ponding condition that has continued to accelerate the roof membrane deterioration and leaking potential of the existing roof throughout the years. This new roof configuration will allow the owner to enjoy a roof system that will last well beyond its 20 year warranties. In addition, added insulation will allow the entire new roof to pay for itself within that same warranty period, making the roof system not only preferable, but, also, yielding a net life cost of zero. Your existing flat roofs can be converted to sloped roofs. You now have the tools to make such a process happen. It is your building. Make an educated choice.
For more information about the many aspects of the metal retrofit roofing market for schools, contact Chuck Howard with Metal Roof Consultants (MRC) at (919) 465-1762. You can also get information about MRC www.metalroofconsultants.net.