By Wade Wilson
Table 3. Comparison of different roofi ng methods with structural member temperatures recorded at 3 PM in degrees Fahrenheit.
Galvalume Roof Unconditioned R-13 Vinyl-reinforced Insulation
Exterior Rafter Purlin
Column† Roof Panel 90
106 110 --
120
Blue Roof Unconditioned R-30 Liner-system Insulation
92 83
80* 79
156
*Purlin temperature is read through the fabric that covers the structural members. †Column temperature measurement could not be obtained. Simple Saver System
Blue Roof Conditioned R-30 “Bag and Sag” Insulation
92 91 94 --
155
Conclusions and recommendations None of these fi ndings are new, or surprising. If you are selling or designing a building that requires a conditioned space or will have people working inside, here are my suggestions:
1. Standing seam roof: In my opinion, a stand- ing seam roof is the best roof currently available. If installed properly, it will never leak and last 20 or more years easily. It also appears that a col- ored roof will have a tremendous impact on the temperature inside the building. There is a lot of information out there about the heat characteris- tics of colored roofs.
2. Liner system with R-30: I love the liner system for insulation—from both an installer’s and building owner’s point of view. The building is aesthetically pleasing, and, of course, the extra insulation does its job, even without heat or air conditioning.
Liner system installation. Liner system installation.
3. Improved installation techniques: There are some areas we need to improve on as install- ers and manufacturers. The eave strut needs to be fi lled with insulation. I would also like to see the manufacturers change to a channel on the rakes instead of an angle. This should also be fi lled with insulation. The base angle should be replaced with a Cee channel where possible and also fi lled with insulation. All the Cee channels used for framed openings should also be fi lled. This would only leave the corners as suspect in terms of the building envelope.
4. Join your local MBCEA: This organization can do more to help with these new challenges than anyone. This group provides a forum for manufacturers, erectors, suppliers, architects and others to address these issues.
These suggestions are the simple things that need to be done fi rst. These are not new ideas, but as an industry we need to embrace them and, more importantly, sell them.
Wade Wilson is the owner of jwWilson Co., a general contractor located in Denver, N.C. He currently serves on the board of directors for the Carolinas Chapter of the MBCEA.
Interior of recently constructed school building with liner system insulation.
www.metalconstructionnews.com
Interior of school, showing the location where temperature measurements were taken.
December 2013 METAL CONSTRUCTION NEWS 9
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