Focus on Roofing: Adhesive Test Methods and Codes Germane to Clay and Concrete Roof Tile Systems

Posted on 11/29/2012 9:54:12 AM By Bob Braun

 adhesive test methods, roofing, roof tile systems, building, construction, adhesive and sealant council

This blog continues the ASC Building Products series for roofing which began with ASC Blog #10. In the previous Blog #15 I began to discuss the history and the specialized applications for foamed roof tile adhesives employed with residential and light commercial buildings.  In this blog I will detail the several code and test requirements for the foamed adhesives that are used to test tile roofing.  Roof tile adhesive, like low-slopped roofing, is tested as an assembly and wind uplift resistance is again a key criteria.    

Due to the many local variations and codes the above details can vary considerably.  In general the roof tile is most popular in the southern, western, and southwestern US.  And that is where the most active code work and development has taken place.  This has led to developing test methods specific to roof tile assemblies as well. 

In the early 1990’s regional codes began to address the foamed adhesives which were based on a one or two part polyurethane.  Early on, Dade County Florida began setting specific detailed requirements based on Florida building techniques in Dade and Broward Counties FL and the damaging effects of hurricane force wind events. Today the Dade County checklist #0150 for clay, concrete, fiberglass reinforced composite, and fiber cement tile systems must be completed in advance of the work and the adhesive product must show a NOA # (Notice of Acceptance #) issued by the county authority.  The NOA # is achieved by completing a series of tests at one of several accredited independent test lab and submitting a completed application.

Due to the many variations in the design and the differences in profile for roof tile (see visual below), some roofs are “air permeable” (which affects wind forces lifting tile from the roof) and some are not. 

common tile profiles, tile, roofing, roof tile systems, building, construction, adhesive and sealant council 

Figure 1: Examples of Several Common Tile Profiles

Thus the tile design as well as the roof height, design, and location will affect the uplift adhesion requirements and testing. For example, below I show a sample of some detailed design issues reflected in the latest ICC-ES Acceptance Criteria AC152 (ACCEPTANCE CRITERIA FOR ADHESIVE ATTACHMENT OF CONCRETE OR CLAY ROOFING TILES):

1.2 Scope: …The underlayment may consist of a mechanically attached 30-pound base sheet and a hot-mopped 90-pound cap sheet (30/90 hot-mopped system) or may be a self-adhering membrane. Underlayments in 30/90 hot-mopped systems shall be of materials complying with …..Roof tiles using adhesive set systems shall have at least two-thirds of the tile’s area free of adhesive contact.

3.2.1 Overturning Moment Tests: Tests shall be conducted in accordance with SSTD 11 for each tile type, tile size, underlayment, adhesive area and substrate combination for which recognition is sought…

3.2.2 Wind Uplift: For each combination of tile type, tile size, adhesive, underlayment, substrate, mean roof height, roof pitch and wind speed for which recognition is sought, the overturning moment determined in accordance with Section 3.2.1 of this acceptance criteria, or the aerodynamic overturning moment determined in accordance with either Section 800 or 900 of SSTD 11, shall be equal to or greater than the aerodynamic uplift moment calculated in accordance with the following formula…

View the full ICC-ES AC 152 document here.

View the ASTM test method C 1568 for uplift.

View the Florida Building Code 2010 Test Application Standard (TAS) No. 106 for the field verification of mortar set or adhesive set tile uplift resistance.

View an interesting video of a wind tunnel comparison of a two part foamed adhesive set and a conventional two nail attached flat tile roof assembly.

A must see recent news video from CNN/WSVN illustrating Florida International University’s “Wall Of Wind” test apparatus capable of producing category 5 hurricane force wind:

 wall of wind, roofing, adhesive and sealant council, building, construction

Figure 2: “Wall of Wind” Assembly at Florida International University, Miami, Florida

And finally, the very recent NSF related article detailing how manufacturers can now test building assemblies or structures using the “Wall of Wind” test apparatus.

Here is a re-cap of several links from Blog # 15 to illustrate the application of foamed adhesives:

Two Component Foamed Adhesive Application.

One Component Foamed Adhesive Application on a Medium Profile Tile.

One Component Foamed Adhesive Application on Flat Concrete Tile.

In Blog #17, I plan to detail how adhesives and sealants are utilized for the most common residential and light commercial roofing product…asphalt shingles.

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