About John Jensen

John Jensen is president of Jensen Roofing Inc., Newcastle, Wash., and the training program manager for the Edmonds, Wash.-based Tile Roofing Institute.

Help Homeowners Understand the Quality Proposition of a Tile Roof

Buying a home is the largest purchase most people ever make. Buyers work intensely to identify their needs and wants, assess the individual benefits of various choices and evaluate the long-term financial return to ensure they make a quality decision. Once living in that new home, kitchen remodels and reroofing can be the largest expenses faced by homeowners.

 In addition to increasing curb appeal, modern tile roofing systems and accessories offer an opportunity to improve the energy efficiency of a home.

In addition to increasing curb appeal, modern tile roofing systems and accessories offer an opportunity to improve the energy efficiency of
a home.

We all have firsthand, daily experience with our kitchen. We know what we like and what we don’t. Advertisements showing features and benefits of new appliances, more spacious cabinets and better lighting are appealing. Learning and planning for a new kitchen is fun and exciting. We know we will use it every day and we can show it off to our friends. We choose to do a kitchen remodel.

Reroofing is different. The process usually starts with a surprise—a roof leak a repairman fails to resolve. Then a second attempt, maybe a third, followed by an explanation that the system has reached the end of its useful and serviceable life. Reroofing becomes necessary to preserve the integrity of the home. It’s not fun and it’s not by choice. Compared to new stainless-steel appliances, soft-close drawers and a built-in wine cooler, it’s not exciting.

With little understanding of modern roofing, the first (and often only) question asked is, “How much is it going to cost?” If lowest initial cost was the only criteria for a roof, we would all have blue tarps overhead.

The true cost of roofing is defined by the life-cycle cost, which includes consideration of the initial cost, life expectancy, potential energy savings and potential insurance discounts.

A quality tile roof installation will set a home apart from neighboring homes now and will be a great investment to help the home garner the best sale price later. This is where a knowledgeable contractor can help a homeowner identify his or her needs and wants, assess the benefits of various choices and calculate the value of the given system.

1. IDENTIFY THE HOMEOWNER’S NEEDS AND WANTS

Residential roofing is a functional part of the building envelope. Its primary purpose is to protect the home and its contents from the elements. Residential roofing is also a largely visible part of a home’s curb appeal. A tile roof will increase the curb appeal of a house when compared to similar homes with less substantial roofing materials.

Concrete and clay roof tiles’ resistance to weathering, hail, high winds and UV means that look of quality will be consistent from the day the roof is installed until the day it helps the homeowner get the best return on his/her original investment by enhancing the home’s curb appeal when the house is sold. Without the excitement of center islands and granite counter- tops, the homeowner needs help to be informed about options and benefits a tile roof can provide.

2. ASSESS THE BENEFITS OF VARIOUS CHOICES

In addition to increasing curb appeal, modern tile roofing systems and accessories offer an opportunity to improve the energy efficiency of a home. The inherent insulation properties created by tile’s high thermal mass can be enhanced with above-sheathing ventilation, or ASV. These raised batten systems can “… offer a significant 50 percent reduction in the heat penetrating the conditioned space compared to direct nailed roof systems that are in direct contact with the roof deck,” says Dr. William Miller, Ph.D., P.E., Oak Ridge National Laboratory, Oak Ridge, Tenn.

The energy savings of ASV is recognized by the California Energy Commission, Sacramento, and included in the Title 24 Energy Code revisions for reroofing and alterations. (Learn more about ASV in “Details”, March/April 2015 issue, page 79.)

PHOTOS: Boral Roofing Products

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Swing Tape and Layout Methods Make Tile Layout Easy

When I see a home with a tile roof, my first thought is, “Nice roof”. A roof goes from “nice” to “Wow, that roof is spectacular!” when the installer pays attention to the details. Some details that make a difference are appropriate flashings, or chimney, skylight and wall metal work that is consistent and does not detract from the aesthetic look of the roof. However, nothing conveys the knowledge and skill of a craftsman more than crisp, clean, straight lines of tile, row after row.

Nothing conveys the knowledge and skill of a craftsman more than crisp, clean, straight lines of tile, row after row.  PHOTO: ROOFWERKS INC., RALEIGH, N.C.

Nothing conveys the knowledge and skill of a craftsman more than crisp, clean, straight lines of tile, row after row. PHOTO: ROOFWERKS INC., RALEIGH, N.C.

Consistent row spacing (exposure) is aesthetically more appealing. It requires dividing the space between the top and bottom of the roof by the number of rows while avoiding a short course at the ridge. Using long division and 1/8- inch increments from a tape measure is one way to achieve this goal. However, that’s a method that challenges my calculator, let alone eager installers who just want to start pounding nails. They may believe it’s easier to deal with the ridge when they get there! It’s no wonder new installers can be intimidated by the layout stage of a tile roof installation. Even experienced installers may miss opportunities to minimize cuts, increase efficiency and achieve that “perfect look” we all admire.

WHAT IS LAYOUT?

Unless precluded by a specific manufacturer’s design, proper clay and concrete tile installation requires a 3-inch minimum overlap. That means a typical 17-inch-long concrete tile has a “maximum exposure” of 14 inches. If the goal is to space the rows evenly, we must first determine the location of the eave course and ridge course. For example, if we find the space between the eave and ridge courses is 140 inches, we can have 10 rows set at the maximum exposure of 14 inches. Perfect!

But what if the distance is only 135 inches? Setting nine rows at 14 inches will require us to cut 5 inches off of our top row. Cutting the tile would remove the fastener holes and tile lugs and make the top course uniquely short, taking away from a precision aesthetic. Most tiles have an “adjustable headlap”, meaning the overlap can be increased. If we set each of the 10 rows at 13 1/2 inches, we would absorb the extra 5 inches evenly over the entire slope with an extra 1/2-inch overlap per row. Row spacing would be consistent; fastener holes and lugs intact; and we would not have to cut tile, drill new holes and throw away the scraps.

The math is not always as easy as an extra 5 inches divided by 10 rows. Eighths and sixteenths don’t work well in long division. The TRI/WSRCA Concrete and Clay Roof Tile Installation Manual, from the Edmonds, Wash.-based Tile Roofing Institute and Morgan Hill, Calif.-based Western States Roofing Contractors Association has a Quick Reference Chart on page 27. It shows proper row spacing for sample eave- to ridge-row measurements. You may find situations where the chart is helpful.

HORIZONTAL LAYOUT USING THE SWING TAPE METHOD

ILLUSTRATION: TRI/WSRCA CONCRETE AND CLAY ROOF TILE INSTALLATION MANUAL

ILLUSTRATION: TRI/WSRCA CONCRETE AND CLAY ROOF TILE INSTALLATION MANUAL


Craftsmen develop “tricks of the trade” that make complicated tasks simple, their work easier or the finished product better. The “Swing Tape Method” does all three.

To avoid the math and use the Swing Tape Method, installers mark their measuring tape at the maximum exposure of tile they are using. Continuing with the example of a 17-inch tile and a 14-inch maximum exposure, the tape will be marked at 14, 28, 42, 56 inches, etc. Using the 135-inch eave- to ridge-course distance in the previous scenario, the installer would place the tip of the tape at the eave-row chalk line and run upslope to find the top-row chalk line at 135 inches. Seeing his tape is marked at 140 inches, the installer would swing his tape in an arc to the left or right until the 140-inch mark aligns with the top-row chalk line. Although the tape is marked in 14-inch increments, the now diagonal lay of the tape has shortened the distance of each horizontal row to 13 1/2 inches. The Swing Tape Method arrived at the same conclusion as the previous arithmetic. The installer marks the underlayment with chalk or a crayon next to each 14-inch increment on the tape measure. He repeats the same process at the other end of the slope and then chalks horizontal lines along the new markings on the underlayment.

Using a tape measure with this method requires marking each row onto the underlayment. This only should be done with chalk or a crayon. Scarring the underlayment with a nail or screwdriver can lead to premature failure of the underlayment.

A modern advancement to the Swing Tape Method uses Layout Tape instead of a marked tape measure. Layout Tape is a paper roll marked with red arrows highlighting the maximum exposure for the tile being used. In this example, the arrows would be at 14-inch intervals. Using the same process as with a marked tape measure, the installer can secure the Layout Tape, placing a red arrow on the top of the eave-row chalk line, then unroll the tape upslope to the top-row chalk line. Using the same 135-inch eave- to ridge-course example, the installer will find a red arrow 5 inches above the top-row chalk line. He will swing the tape to the left or right until the red arrow lines up with the top-row chalk line. The red arrows become the targets for the horizontal chalk lines. Because the Layout Tape is left in place, the installer avoids the step of marking each and every row on the underlayment.

PICTURE PERFECT

Of course not all roof slopes are simple rectangles. Some roof designs are quite complicated and as installers we have to play the hand we are dealt. The Swing Tape Method can help you make the best of challenging situations by allowing you to virtually try out different layout options. If a slope has multiple ridgelines, you can set the tape to the most beneficial location. This may reduce your cutwork or put a short course in the least visible location. On larger sections, you may choose to adjust the row spacing to better accommodate ridgelines, headwalls or dormers. Be aware that midslope adjustment of exposure can result in a change to the diagonal line of the tile sidelaps but does not affect function.

Using the Swing Tape Method with Layout Tape or a marked tape measure appropriate for the tile being used will ensure proper exposure. It will also reduce cutting and increase your efficiency while laying the foundation for a picture- perfect installation.

SWING TAPE METHOD STEPS

1 Determine eave-course placement (consider eave closure, gutter, desired overhang) and snap a line to place head of the tile or top of the battens if battens are to be used.
2 Determine top-row placement (consider ridge riser board, ventilation, etc.) and snap a line to place head of the tile or top of the battens if battens are to be used.
3 Using Layout Tape or a marked tape measure, place an arrow or mark at the eave-course line. Measure straight to the ridgeline. Swing the tape to the left or right until an arrow or mark aligns with the top-row chalk line.
4 If you are using Layout Tape, fasten the tape. If you are using a marked tape measure, you must mark the underlayment at each mark on the tape measure.
5 Repeat this process at the other end of the roof. Snap lines between the arrows or marks on the underlayment.

The Benefits of Above-sheathing Ventilation

We know proper ventilation of the attic space is an important part of construction. But what is “above-sheathing ventilation”?

Most roofing materials lay directly on the sheathing. Heat from solar radiation and interior heat loss from the conditioned space are easily transferred through the deck and roof system. This can increase energy costs and cause ice damming. The build-up of heat and extreme temperatures wings can also reduce the life of underlayment and other system components.

Tile roofs have an air space between installed roof tiles and the roof sheathing. This space reduces heat transfer and allows heat buildup to dissipate from the sheathing and roofing materials. This above-sheathing ventilation, or ASV, inherent to tile roof installations can be enhanced using counter battens, shims or manufactured systems to raise the horizontal battens above the roof deck. The system design will vary with the environmental challenge and goals. Specific examples are described below.

The Elevated Batten System by Boral Roofing uses treated 1 by 2s with high-grade plastic pads, a vented eave riser flashing and vented weather blocking at the ridge. With these components in place, heat transfer is minimized and heat buildup is dissipated, which reduces energy costs.

The Elevated Batten System by Boral Roofing uses treated 1 by 2s with high-grade plastic pads, a vented eave riser flashing and vented weather blocking at the ridge. With these components in place, heat transfer is minimized and heat buildup is dissipated, which reduces energy costs.

Energy Conservation in Hot Climates

In hot and dry climates, the natural ASV and thermal mass of the tile provide a layer of insulation when exterior daytime temperatures are greater than the conditioned space in the home. Vertical counter battens or shims that raise the horizontal battens increase this space and the corresponding benefit. The addition of vented eave riser flashing and ridge ventilation completes an energy-saving ASV system. The system shown below is the Elevated Batten System made by Boral Roofing, which uses treated 1 by 2s with high-grade plastic pads, a vented eave riser flashing and vented weather blocking at the ridge. With these components in place, heat transfer is minimized and heat buildup is dissipated, which reduces energy costs. The upgraded ASV reduces temperature extremes that shorten the life of the underlayment and other roofing components. These benefits are achieved with no mechanical or moving parts.

Cool and Humid Climates

The same installation can provide a different benefit in cool and humid regions. The Tile Roofing Institute and Western States Roofing Contractors Association’s Concrete and Clay Tile Installation Manual for Moderate Climate Regions says that in areas designated “Cool/Humid” zones, “Batten systems that provide drainage/air-flow (shims, counter battens or other approved systems) are required.” The area designated “Cool/Humid” in the current manual runs from approximately Eureka, Calif., to the Pacific Northwest, west of the Cascade Mountains. In this climate, moisture-laden air can migrate under the tile and condense in the space between the tile and roof deck. The underlayment is there to protect the sheathing but if the battens are raised above the deck, condensation will be reduced. Raised battens also allow moisture under the tile to escape to the eave. When roof tiles are fastened to a raised batten, underlayment penetrations are minimized.

Cold and Snowy Regions

Ice dams are one of the most damaging phenomena roofing contractors face. Snow movement on roof surfaces can cause damage to people and property. The goal in cold and snowy environments is to prevent ice dams by enhancing the ASV under the tile roof. Typically, a more substantial air space is created using larger vertical battens. A well-designed “cold roof” system that includes proper snow retention is the solution.

The TRI/WSRCA Concrete and Clay Tile Installation Manual for Moderate Climate Regions refers installers to the TRI/WSRCA Concrete and Clay Roof Tile Design Criteria Installation Manual for Cold and Snow. Regions “in locations where the January mean temperature is 25 deg. F or less or where ice damming often occurs”.

For more information and to download the Tile Roofing Institute’s installation manuals, visit the Tile Roofing Institute at TileRoofing.org.

ILLUSTRATION: Boral Roofing

Tile Roofing: Closed Valleys with Low-profile Tile

Batten extensions are installed on standard tile W valley metal.

Photo 1: Batten extensions are installed on standard tile W valley metal.

A common failure point on steep-slope roof systems is at valleys. Often, aging material, improper fastening, lack of maintenance and ice dams make valleys vulnerable. A common cause of valley troubles with tile roofing occurs when flat tiles are used in areas where closed valleys are preferred and a simple installation requirement is missed.

The Tile Roof Institute (TRI) Concrete and Clay Tile Installation Manual for Moderate Climate Regions allows for open (flashing exposed) and closed (tiles meet over flashing) valley installations. Installers develop a preference based on their experience with the local climate. Contractors also consider job-specific environmental conditions, aesthetic preferences, pitch and maintenance needs when choosing from valley-installation options.

Although there are a wide variety of flashing and installation options for valleys, one important requirement is often overlooked and can cause leaks with low-profile tile. The specification is listed on pages 48 and 49 of the installation manual: “When a flat profiled tile is installed as a ‘closed valley’, a ribbed valley metal or single crown valley metal with batten extension shall be used.”

Batten extensions are installed on standard tile W valley metal.

Click to view larger.

Unobstructed water flow in the valley flashing is critical. A flat tile installed directly onto standard valley flashing in a closed method restricts water in the valley flashing during heavy rains and may cause it to overflow. This can speed degradation of the underlayment and may cause rot in the battens and decking. A closed-valley installation can be repaired by replacing the standard tile valley flashing with the correct ribbed metal or by adding a batten extension to each row (see photo 1).

Because medium- and high-profile tiles have a natural cavity between the flashing and tile, this requirement only applies to low-profile tile. According to the TRI installation manual, the definition of a low-profile tile is, “Tiles, such as flat tile, that have a top surface rise of 1/2 inch or less.” Most tiles with a wood grain, lined or brushed surface still fall into the low-profile category and will require batten extensions or ribbed valley flashing.

An elevated batten system with ribbed valley flashing.

Photo 2: An elevated batten system with ribbed valley flashing. PHOTO: Boral Industries

When using a counter-batten system, or raised batten, the battens themselves can be extended into the valley because they are elevated on a pad or shim. In photo 2, a ribbed valley flashing and an elevated batten are used. Fasteners are not installed in/through the valley flashing.

Tile installers are craftsmen and each develops his or her own approach to valley details. Depending on the length of the valley and the tributary area, installers may flare or gradually open the width of the valley tile cut. Experienced installers may make a cut (dog ear) to the point of the tile that is overlapped by the succeeding row. Before accessory products, like ribbed valleys and batten extensions, were commercially available and before manufacturers improved the lug design, installers often removed lugs with their hammers. They developed propping and gluing skills to avoid creating a dam with their installation. Now the accessories and flashing designs make this type of installation better and easier.

Despite the variety of tiles within the low-profile category—some are flat on the back side and fastened directly to the deck, some have lugs on the back that can also utilize battens for attachment— all low-profile tile installed in a closed-valley method requires ribbed flashing or batten extensions unless precluded by manufacturer design and/or approved by the local building inspector.

An elevated batten system with ribbed valley flashing.

Click to view larger.

Because of Florida’s wind and weather extremes, TRI and the Florida Roofing, Sheet Metal and Air Conditioning Contractors Association collaborated on Florida High Wind Concrete and Clay Roof Tile Installation Manual, which also is available on TRI’s website.

PHOTOS: TILE ROOFING INSTITUTE, unless otherwise noted