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Roof tile installation (C) Daniel Friedman Tile Roof Connections for High Wind & Seismic Areas

Roof tile connectors & fasteners for high wind or seismic areas:

This article describes the special connection methods used to secure clay tiles to roofs in high wind, hurricane, or seismic areas.

This article series explains clay tile roofing types, clay roofing tile inspection, tile roofing diagnosis, & tile roof repair.

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High-Wind and Seismic Installation Requirements for Tile Roofs

Figure 2-23: Hurricane clips for clay roof tiles (C) J Wiley, S BlissThis article series discusses best practices in the selection and installation of residential roofing. This article includes excerpts or adaptations from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) , by Steven Bliss, courtesy of Wiley & Sons.

Our page top photo shows a very simple roof installation detail in area where high winds are not much of a concern, San Miguel de Allende, Mexico. Notice that except at the vertical wall abutment these soft clay tiles are simply placed by gravity with no fasteners whatsoever. This roof would be both destroyed and dangerous in high wind or seismic area.

At left (and discussed below) is are details about hurricane clip fasteners used with clay tile roofs in areas of extra risk.

In areas prone to high winds, such as Florida, setting the tiles in mortar was once considered the strongest system.

However, newer anchoring systems using wires, special clips, and, in some cases, specialized adhesives have proven more reliable and have replaced mortar-set systems as the preferred approach.

Wire and clip systems also perform better than rigid attachment systems in seismic zones, as the flexible systems tend to absorb the shockwaves of an earthquake and protect the tiles from cracking.

Building codes vary in their requirements for high-wind and seismic areas but most permit one or more of the anchoring systems described below.

Model specifications for high-wind installations are available in the Concrete and Clay Roof Tile Installation Manual, jointly published by the Florida Roofing, Sheet Metal and Air Conditioning Contractors Association and the Tile Roofing Institute. General guidelines for high-wind installations or roofs over 40 feet above grade include:

Twisted Wire Requirements for Tile Roof Installations

Figure 2-22: Twister wire to secure clay roof tiles (C) J Wiley, S Bliss

This approach is used on roofs ranging from 2:12 to 24:12 in seismic zones and areas with moderate winds. Rather than nail the tiles to the roof, each tile is wired to a length of twisted 12-gauge wire (galvanized, copper, or stainless steel) running from eaves to ridge under each vertical course of tiles.

[Click to enlarge any image]

The twisted wire has a loop to tie into every 6 inches and is attached every 10 feet with special anchors, making relatively few holes in the underlayment (see Figure 2-22).

Because wire systems allow some movement, seismic forces do not tend to break the tiles.

Also, damaged tiles are easy to replace by snipping the tie wire and wiring in a new tile. Installation is labor-intensive, however, compared to nailing.

Hurricane Clip Requirements for Tile Roof Installations

Figure 2-23: Hurricane clips for clay roof tiles (C) J Wiley, S Bliss

A hurricane clip, also known as a storm clip or side clip, is a concealed L-shaped metal strap designed to lock down the water-channel side of a roofing tile near the nose (Figure 2-23).

Hurricane clips for roofing materials are well-suited to concrete tile and are used in conjunction with nails, screws, or other systems that secure the head of the tile.

Watch out: Hurricane clips for clay roofing tiles are approved for use in some hurricane areas, but they should be combined with a nose clip or similar device for maximum protection. Used alone, they may deform or loosen after several storms.

Nose Clips or Nose Hooks: Requirements for Tile Roof Installations

Figure 2-24, Nose Clips for Roofing Tile Installations (C) J Wiley, S Bliss

Also known as nose hooks, butt hooks, or wind locks, these simple metal clips hold down the bottom (nose) end of a roofing tile to prevent strong winds from lifting and breaking the tiles (Figure 2-24).

Nose clips are nailed in place through the underlying tile or attached to the tie wires in wire systems.

Nose hooks or nose clips on clay tile roofs are compatible with all methods of tile attachment and are recommended for high-wind areas and slopes greater than 7:12.

The main drawback to nose clips is that they are visible at the nose of each tile, which some homeowners find objectionable.

Tile Nail Option for Tile Roof Installations in Seismic or High Wind Areas

Figure 2-25: Nailing optiosn for clay or concrete tile roofs in high wind or seismic areas (C) J Wiley S Bliss

This innovative fastener, used mostly with S-tile or two-piece Mission tile, functions as both a nail and a nose clip. Because the nail is driven about 6 inches above the tile, there is no risk of breakage and the nail hole can be easily sealed with mastic (Figure 2-25).

Tile nails are approved for all slopes and are especially useful in high-wind areas and on very steep pitches such as mansards.

Hurricane or seismic tile nails are also useful for securing the first course of two-piece Mission tile.

Examples include the Tyle Tye® tile nail from Newport Tool & Fastener Co. and the Hook Nail from Wire Works, Inc.

Using Tile Adhesives for Clay or Concrete Tile Roof Installations

Another way to prevent uplift in windy conditions and to keep tiles from rattling on steep slopes is to set the butt edge of each tile in a dab of roofing cement. Over time, however, roofing cement may become brittle and fail. New proprietary tile adhesives promise to last longer and stay flexible over time.

In hurricane-prone areas, some contractors are applying adhesive to every tile—in some cases combined with other fastening methods, such as twisted wires.

While long-term performance has not been well-established, testing by manufacturers has demonstrated that adhesives can outperform mortar systems in hurricane-force winds.

- - Adapted with permission from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) .

Resources: Roofing Materials & Equipment Suppliers

Manufacturers

Concrete Roof Tiles

Clay Roof Tiles

Tile Fasteners and Adhesives

More Information about Roofing Materials, Methods, Standards

- - Adapted with permission from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) .

 


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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: where are clay or concrete root tile clips required?

(Apr 30, 2015) Adam said:
Does each and every tile receive the clips or just the bottom course?

Reply:

Adam in storm or high wind areas every course and tile should be tied down. In other areas that may not be required. For example in central Mexico where we are away from high winds and hurricanes clay roof tiles are simply held in place by gravity.


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