In 2006, at Hawthorne Elementary School South, Vernon Hills, Ill., I restored a ballasted EPDM roof that I designed in 1985 and observed, full- time, while it was installed in January 1986 (see Photo 1). The restoration included lap-seam enhancement with self-adhering cover strips, target patch installation at all roof drains, re-flashing of all roof curbs and penetrations, re-flashing the gravel-stop flange, and removal and replacement of eight sky- lights (see photos 2 and 3). The restoration cost 52 cents per square foot, or $52,000, versus the $400,000 cost to remove and replace the roof system. This restored roof is still performing today.
During my RCI presidency, my motto was “Learn, Share, Grow”; thus, I have shared all my restoration details on the Washington, D.C.-based EPDM Roofing Association’s website.
ROOF-COVER REMOVAL, ENHANCED WITH ADDITIONAL INSULATION
As many of the new age roof covers were membrane roof covers, a possibility presented itself that was not previously perceived: removing only the roof cover and leaving the existing insulation in place. We have recently completed and currently are bidding several such projects.
EXISTING ROOF MEMBRANE AS VAPOR RETARDER
Because of the long-term aging of membrane roof covers, they have the potential to be left in place and reused as a vapor retarder. A dew-point analysis will determine the amount of insulation required above the roof cover; in the Chicago area, it is 5 inches installed in two layers of 2 1/2 inches (see Figure 2 and photos 6 and 7). Certainly any minor deficiencies in the existing membrane need to be repaired; roof drains extended (see Photo 8) and roof edges often modified. However, the benefits are great: reduced costs, minimization of interior disturbance, less material to the landfill and enhanced thermal performance.
MEMBRANE REMOVAL, INSTALLATION OF NEW ROOF COVER
The IECC, or International Energy Conservation Code, requires that if you expose the insulation you must increase the insulation to achieve the required thermal R-value. Many new age roofs have considerable insulation and the potential may exist to remove the existing roof membrane and install a new roof membrane. Prudency suggests that at least a minimal layer of insulation or cover board be installed.
Although all of these examples may be options, the licensed roof designer must use professionalism to make prudent engineering decisions; do what is right for the client; and meet all code requirements, including wind-uplift resistance and roof-edge sheet-metal compliance (ANSI-SPRI RP1).The face of the roofing industry is changing rapidly and so are available reroofing options. Although not all existing roofs are candidates for the innovative solutions I’ve mentioned, some are, and the potential to save our clients money, reduce interior disturbance and be environmentally prudent is too much to ignore.
PHOTOS: HUTCHINSON DESIGN GROUP LLC
MORE FROM HUTCH
“Roofs Are Systems”, January/February 2014, page 52
“Roof Decks”, March/April 2014, page 54
“Substrate Boards”, July/August 2014, page 52
“Vapor Retarders”, September/October 2014, page 52
“Insulation”, November/December 2014, page 50
“Wind-damaged Roof Systems”, January/ February 2015, page 60
“Cover Boards”, September/October 2015, page 60
“The Roof Cover”, November/December 2015, page 42
Pages: 1 2