Manual receives ICBO approval

In June 2001, the Roof Tile Institute (RTI) and Western States Roofing Contractors Association (WSRCA) released an industry-based installation manual that provides recommendations for installing concrete and clay roof tiles in moderate climate regions of North America.

The manual, Concrete and Clay Tile Design Criteria Installation Manual for Moderate Climate Regions, was developed to provide the best installation practices, industry standards and available code requirements in a single manual. The manual had an effective date of Jan. 1, 2002, which is when the changes in the manual were required to be followed in the field by roofing workers.

Before the manual's release, there were more than 50 manuals written by various tile manufacturers throughout North America. Almost all North American tile manufacturers now have formally replaced their manuals with the new manual.

As RTI commenced a series of training workshops in fall 2001 in the West, it became apparent the new manual was not only highly informative but also well-received in the design community. But some resistance emerged as traditional roofing practices that were not included in the existing tile installation guides or new industry manual were being touted as the preference of roofing contractors. In one session, I was confronted with the statement, "We will not comply with these changes until we see it in writing from the code authorities." In this case, the person was referring to the Uniform Building Code (UBC).

Although the manual refers to the UBC section that requires roof system installers to follow manufacturers' printed installation instructions, this did not seem to faze the strongest objectors who were worried about increased costs incurred when following the manual's guidelines. Subsequent to that seminar, we met with International Conference of Building Officials Evaluation Service (ICBO-ES) staff to discuss how best to respond to such objections. Because the manual was to be a cornerstone of RTI's future, we wanted to defend the manual through the codes. From that meeting, RTI was able to obtain a letter from ICBO-ES confirming that UBC requires installers to follow manufacturers' installation instructions. The second point that emerged from our discussions was the concept of submitting the manual to ICBO-ES to obtain a formal report number.

In January 2002, RTI began revising the first printed version of the manual for submission to ICBO-ES. This required revisions to remove any permissive language. The code authorities require language to be specific in what "is" or "is not" allowed. Permissive words, such as "may," "might" and "can," are not allowed. Because most installation guides are deemed marketing materials, they generally are not specific.

RTI's technical committee, therefore, reviewed each page of the manual to locate such references. We not only needed to identify potential revisions but also had to determine whether revisions would eliminate options that should be available to roofing contractors or design professionals. When considering these revisions, we relied upon WSRCA members' input to make sure the revisions were reasonable from roofing workers' standpoints. We also needed our manufacturing members to be comfortable with proposed revisions.

In April 2002, we submitted the revised manual to ICBO-ES and received its written comments almost immediately, requiring only a few minor changes.

In September 2002, the revised manual was printed bearing the new report number ICBO-ER 6034P. The new manual has replaced the January 2002 version. After release, tile manufacturers then submitted revisions to their existing ICBO-ES reports to reference the manual as the current installation instructions for their companies.

The revised manual does not contain any significant revisions from the first edition. The minimum requirements listed in the first manual will remain.

Now that we have obtained our formal ICBO-ER report number, revised AutoCAD drawings can be downloaded from RTI's Web site, www.rooftile.org, and will be available on CD-ROM by the end of 2003.

RTI has identified wind design as the next major topic to be covered and has begun to develop a third manual that will address design options available in south Florida, as well as other regions of North America and Hawaii. This manual will address alternative methods for determining wind-uplift resistances for tile and the ability of mechanical and adhesive-based roof systems to meet them. We expect this manual to be available in spring 2004. When completed, the tile industry will have assembled three industry-based installation guides that will cover moderate climate, cold climate and high-wind application regions of North America.

Because developing industry-based installation guides is a constantly evolving task, we will try to keep the roofing community informed via technical bulletins on RTI's Web site. Since the release of the manual's second edition, we have received requests for additional new details about flashings, ventilation and valley treatments. We will develop technical bulletins to address these issues until the next edition of the manual is developed. We welcome input for additional items from the roofing community. E-mail any questions or concerns to info@rooftile.org.

Richard K. Olson is president of the Roof Tile Institute.

Questions raised

Although the Roof Tile Institute attempted to address all major areas of roof system design in the development of the revised manual, it is impossible to cover every issue or option used in the field. Following are a few recurring questions that are worth noting:

1. Valley treatments—On pages 45 to 48, we have attempted to show various valley options that might be considered. The option of a closed valley was not shown but is allowed. Because a valley's various components were needed in the illustrations, it was better to show an open valley in the drawings.
   
   
2. Valley metals—Again, we were not able to provide drawings to address all designs of valley metals, so we picked the most common designs available. Footnote 9 on the drawings states, "Valley designs must be able to control and discharge the expected water flows." This provides for numerous options but raises the concern for designers or roofing professionals to consider water flow abilities. The issue of tributary water flows for valleys and even chimney flashing always should be considered in the design process.
   
   
3. Hip and ridge treatment—On pages 49 and 50, we have provided new, improved drawings that will show the options and intent for sealing hips and ridges. When mortar is being used, it should be noted that the Uniform Building Code and standard building codes still mandate that it cannot contact bare wood.
   
   
4. Watershedding abilities of tile—When installed correctly, tile can provide watershedding ability for roof systems in moderate climate areas. There have been those who have said tile purely is decorative, which is incorrect. This only is true when a roof's slope is less than 3-in-12 (14 degrees) or in areas that have wind-driven rains, such as south Florida.

WEB
EXCLUSIVE

• Web exclusive: Click below for more information.
• Additional information about the manual and Olson's May 2002 article.