In "What roof system would you install?" July issue, page 18, we asked whether you agree with contractors' roof system recommendations.

Below are two readers' responses.

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The most critical element for any roof system is the building design, and in the installation of any roof system, it is constant supervision of work. I insist contractors provide a superintendent who does not physically participate in any part of the construction process and is at the site for every hour that a crew is at work. I provide drawings and specifications fully describing the roofing material and installation. Additionally, attendant construction observation is critical.

I agree with Bob Daly's opinion about coal tar pitch. A hospital client had original coal-tar-pitch roof systems installed in 1948, which were still in excellent service when I retired in 1993. My choice for steep-slope roof systems is clay tile set in mortar over a modified bitumen finish ply. I designed a tile roof for a residence in South Dade County, Fla., which survived the worst of Hurricane Andrew without the loss of a single tile from separation. Tile was broken from flying debris, but no other loss to the building.

Good roofing contractors and roofing installers are a treasure in my practice. Roofing is the most delicate and critical element in any building, and too often, it is "out of sight and out of mind."

Harold Seckinger
Harold Seckinger Architect

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I read, with interest, your article entitled "What roof system would you install?". As I read, I continued to ask myself, "why does no one ever have a preference toward PVC?" The criteria mentioned the installation is Midwest. Living in northern Michigan makes Midwest my backyard. PVC is our company's choice for several reasons.

1. The temperate weather window is near nonexistent, but reasonable weather still is necessary. Other membranes require near-perfect conditions to maintain seam integrity. Anything from a skiff of snow, light mist, humidity to job-site debris will contaminate the membrane seams. This results in shutting down the site or "forcing the job" and dealing with the consequences. (Does all the residual insulation on the seam tape get removed before the seal is made?)
   
   
2. Mention was made of the advantages of fully adhered EPDM, both puncture resistance (try pushing a pencil through equal thicknesses of EPDM vs. PVC) and ponding water. I believe PVC roof systems are the exception.
   
   
3. Coal-tar pitch was noted as the longest-lasting roof out there. Our company has been around for 78 years, has put down coal-tar pitch and continues to remove old ones. They do have a track record that is indisputable. Is the makeup of coal-tar pitch as good as it was 50 years ago? More than any other roof systems, its longevity is dependant on workmanship and moisture-proof conditions (both application and storage). Plus, the kettle being pulled onto the job site is about as welcome as your neighbor's septic being pumped though the kettle usually stays around longer. Better PVC manufacturers have made roofs that lasted more than 35 years most with little maintenance. Add the cost of coal-tar pitch, what advantage is there?
   
   
4. Modified bitumen has many of the disadvantages of other built-up roofing products without the advantage of four plies.
   
   
5. I agree with the need for metal roofing on the steep-slope areas. I agree on this application but would like to insert that as these slopes get flatter, lower valleys and dormers increase. Our company has been satisfied with using fully adhered PVC with the addition of mock PVC ribs.

By the looks of the article, it seems our company is 180 degrees out of phase with the majority. I realize there have been some really poor performing PVC membranes out there (we, unfortunately, installed some of it in years passed). That does not change the fact that there are PVC products achieving noteworthy goals.

Craig A. Bloxsom
Bloxsom Roofing & Siding Co.

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