Increased Thermal Values Affect an Existing Roof Edge

CONVEYING THE DESIGN SOLUTION TO CONTRACTORS

The art of detailing is the expression of design solutions in graphic form in a manner in which the field crew can understand and implement. All too many designers try to provide drawn details that are not fully developed to communicate design intent to contractors—often with dire results.

Here the new insulation heights can be seen and show the new roof edge, utilizing steel tees to support the wood blocking.

Photo 8: Here the new insulation heights can be seen and show the new roof edge, utilizing steel tees to support the wood blocking.

Most roofing crews I know are only fair mind readers. The final design should be graphically clear and communicative. All components should be noted, as well as how they are to be installed. Be specific. Remember, you are the designer. As the famous architect Mies Van de Rohe once said, “God is in the details”. Some of these details can become very complex and, thus, I suggest step-by-step details be utilized. It is not uncommon to have three or more progression details. A designer with a background in construction will be very helpful.

The proper specification should, of course, provide the material particulars, many of which can be noted on the detail. A quality detail, well drawn and properly noted, in my opinion, will result in better results than just a specification.

GETTING IT DONE

Once the design is conceived, the challenge then moves to achieving it. A well-designed solution, properly graphically delineated, really doesn’t need an installation shop drawing, though a fabrication shop drawing for the curb might be needed.

On this project, the roof edge is being raised with a prefabricated roof curb, custom fabricated to conform to the existing gravel stop.

Photo 9: On this project, the roof edge is being raised with a prefabricated roof curb, custom fabricated to conform to the existing gravel stop.

The concept and installation should be reviewed in the preconstruction meeting, attended most importantly by the foreman who will be onsite. I have found that explaining the design concept and importance of various components, asking for the contractor’s input, brings them into the team and often gets their buy-in.

Another key to achieving positive results is procuring a correct mock- up. The first order of business is to be sure that the mock-up is installed by the same personnel who will be installing it onsite. This is an important matter that should be required in the specifications. I have found that being onsite for the first few days of installation to ensure appropriate installation and continuity is vital.

Once the roof edge curb has been installed, the roof system can be in- stalled. This is followed by roof edge sheet-metal cladding.

Note how nicely a prefabricated roof curb quickly and structurally raises the roof edge to accommodate new roof insulation.

Photo 10: Note how nicely a prefabricated roof curb quickly and structurally raises the roof edge to accommodate new roof insulation.

FOREFRONT OF CHANGE

Energy conservation is something all school children are now learning. The reduction of greenhouse gases can be greatly affected by a reduction in the use of fossil fuels to produce energy.

The roofing industry is on the fore- front of being able to substantially contribute to energy-use reduction. Will it be easy? Not very often. Achieving something of substantial benefit requires intelligence, empathy, sacrifice, talent, dedication, perseverance and belief.

With tapered systems being installed on buildings that were once dead level, the new roof edge height needed was great, sometimes exceeding that of a 2 by 12. To accomplish the needed height, the author’s firm started designing and specifying custom roof edge curbs, some up to 39 inches in height, which have worked extremely well.

Figure 4: With tapered systems being installed on buildings that were once dead level, the new roof edge height needed was great, sometimes exceeding that of a
2 by 12. To accomplish the needed height, the author’s firm started designing and specifying custom roof edge curbs, some up to 39 inches in height, which have worked extremely well.

While we may not all agree on the whys and needs, we should all band together to achieve our country’s goal of energy conservation.

So go ahead. I challenge you: Raise the roof edge.

PHOTOS and ILLUSTRATIONS: 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

On this project, the roof edge needed to accommodate more than 25 inches of insulation to provide slope to interior drains. In the design process, it was decided to match the height of an adjacent precast wall. The curb is already covered with fully adhered EDPM and was ultimately covered with metal siding.

Photo 11: On this project, the roof edge needed to accommodate more than 25 inches of insulation to provide slope to interior drains. In the design process, it was decided to match the height of an adjacent precast wall. The curb is already covered with fully adhered EDPM and was ultimately covered with metal siding.


“Cover Boards”, September/October 2015, page 60
“The Roof Cover”, November/December 2015, page 42
“The Changing Face of Roof Replacement”, January/February 2016, page 38

Pages: 1 2 3

About Thomas W. Hutchinson, AIA, FRCI, RRC, CSI, RRP

Thomas W. Hutchinson, AIA,FRCI, RRC, is principal of Hutchinson Design Group Ltd., Barrington, Ill., and a member of Roofing’s editorial advisory board.

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