There are several different methods of applying three-tab strip shin-gles. The designs usually correspond to the amount removed from the first shingle in each successive course. Removing different amounts from the first shingle staggers the cutouts so that one course of shingles does not line up directly with those of the course below. Start first courses of shingles with full or cut shingles, depending on the pattern desired.
SIX-INCH PATTERN
This design is often called “the cutouts that break on joint halves.” The six-inch pattern starts each succeeding course with shingles that are 6 inches smaller than the starter shingle in the preceding course. The first course starts with a full-length shingle. The second course starts with a shingle that has had 6 inches removed. The third course starts with a shingle that has had 12 inches removed, and so on through the sixth course, which starts with a shingle that has had 30 inches removed.
Adjacent shingles in each course are all full length. The seventh course again starts with a full-length shingle, and the pattern is repeated every six courses. Figure 7-3 illustrates the pattern.
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CHAPTER SEVENDeck Underlayment
Start 2nd course with 6" removed Start 3rd course with 12" removed
Shingles overhang drip edge 1/4" to 3/4"
Starter strip Drip edge Drip edge
Start 1st course with full shingle 5" exposure
Self-sealing adhesive
F I G U R E 7 - 3 Six-inch pattern.
FIVE-INCH PATTERN
This application is similar to the six-inch pattern, except that the sec-ond through seventh courses are each 5 inches smaller than the pre-ceding one. The first course begins with a full shingle. The second course starts with 5 inches removed from the first shingle, and so on through the seventh course, which has 30 inches removed from the first shingle. Adjacent shingles in each course are full length. The pat-tern is repeated every seven courses. One alpat-ternative method calls for starting the eighth course with 11 inches removed from the first shin-gle (Fig. 7-4).
FOUR-INCH PATTERN
This one is often called “the cutouts that break joints on thirds.” The four-inch pattern design is illustrated in Fig. 7-5. Start the first course with a full shingle. Start the second course with 4 inches removed from the first shingle, the third course with 8 inches removed, and so on through the ninth course, which has 32 inches removed from the first shingle. Adjacent shingles in each course are full length. The tenth course again begins with a full-length shingle and the pattern is repeated every nine courses.
Deck Underlayment
Start 2nd course with 6" removed Start 3rd course with 12" removed
Shingles overhang drip edge 1/4" to 3/4"
Starter strip Drip edge Drip edge
Start 1st course with full shingle 5" exposure
Self-sealing adhesive
F I G U R E 7 - 4 Five-inch pattern.
Note: Never use an alignment system where shingle joints are closer than 4 inches to one another.
RANDOM SPACING
This pattern can be achieved by removing different amounts of mater-ial from the rake tab of succeeding courses in accordance with the fol-lowing principles.
■ The width of any rake tab should be at least 3 inches.
■ The cutout centerlines of any course should be located at least 3 inches laterally from the cutout centerlines in both the courses above and the courses below.
■ The rake tab widths should not repeat closely enough to cause the eye to follow a cutout alignment.
Starting the first course with a full-length strip indicates the length of the starting tab for each succeeding course. This procedure is nec-essary to produce satisfactory random spacing.
RIBBON COURSES
The use of a ribbon course every fifth course strengthens the horizon-tal roof lines and adds a distinctive, massive appearance that many
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CHAPTER SEVENUnderlayment Deck
Start 2nd course with 4" removed Start 3rd course
with 8" removed Shingles overhang
drip edge 1/4" to 3/4"
Starter strip Drip edge Drip edge
Start 1st course with full shingle 5" exposure
Self-sealing adhesive
F I G U R E 7 - 5 Four-inch pattern.
homeowners find desirable. A preferred method of ribbon course application involves a special starting procedure that is repeated every fifth course.
■ From the tip of a 12-inch-wide strip shingle, cut away 4 inches.
This provides an unbroken strip 4 × 36 inches in size and a strip 8 × 36 inches in size that contains the cutouts.
■ Lay the 4-×-36-inch strip along the eaves.
■ Cover this strip with the 8-×-36-inch strip, with the bottom of the cutouts laid down to the eaves.
■ Lay this first course of full shingles (12 × 36 inches) over the other layers (see Fig. 7-6) with the bottom of the cutouts laid down to the eaves.
Note: Offset cutouts between the first two layers as explained for six-inch, four-inch, or random spacing patterns.
“A”: Full shingle
“B”: 8"-wide section
“C”: 4"-wide section Ribbon and starter courses triple thickness at buttline
F I G U R E 7 - 6 Ribbon courses.
Repeat this procedure every fifth course, or after a predetermined number of courses, by aligning the ribbon course with the tops of the cutouts of the fifth course. This method produces a triple-thickness buttline every fifth course.
Note: Very steep slopes tend to reduce the effectiveness of factory-applied, self-sealing strip adhesives, especially on the colder or shaded areas of the roof.