You can shingle a low-pitch roof using standard three-tab asphalt shingles or using rolled roofing. Three-tab shingles are best applied to low-pitch roofs when the weather is warm, so that the tarred backsides of the shingles will create a tight enough seal to keep the elements from seeping up and under the shingles into the roof. Rolled roofing is best when the roof pitch is only slightly greater than level. This guide covers both methods.
Things You'll Need
- Three-tab shingles or rolled roofing
- Nail gun, or hammer and nails (optional)
- Heat gun or blow torch (optional)
- Utility knife
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Lay the first shingle at a lower corner of the low-pitch roof. Justify it with the edges of the roof. Secure it to the decking with nails through the upper (adhesive, non-decorative) portion of the shingle.
Lay the second shingle next to and abutting the first one. Secure it in the same way you did the first shingle.
Repeat Step 2 until you reach the end of the row and can no longer fit a whole shingle. Use a razor blade to score the backside of the last shingle where it meets the end of the roof and snap it apart. Nail down the partial shingle and set the waste material aside.
Use the razor blade to score the backside of a shingle in half cross-wise and snap it in two. Lay one of the halves above and overlapping with the beginning of the first row of shingles. It should entirely overlap the adhesive portion of the shingle below. Nail it down.
Lay the rest of the row with full shingles, trimming the last shingle to fit. Always make sure the shingles above overlap the adhesive parts of the shingles below.
Start the next row with a full shingle and complete the row as you did in Steps 3 through 5, by trimming the last shingle to fit. Continue alternating half and full shingles until you reach the top of the roof.
Cap off the backside (highest end) of the low-pitch roof with cap shingles. Start at one end and fold the first cap shingle over the back edge, decorative portion facing the edge of the roof, and secure it in place with a nail in the roof decking and a nail in the eave.
Overlap the first ridge shingle with a second ridge shingle such that the first ridge shingle's non-decorative portion is completely covered. Continue in this way until the back end of the roof is covered. Trim the adhesive portion off the last ridge shingle, secure it, and cover the two nail heads with roofing cement.
Mark the end of the rolled roofing and snap a chalk line across the bottom (tar side) of the roll to create a straight, 90-degree angle that will fit the edges of the low-pitch roof.
Trim the starter end of the rolled roofing along the line you made in Step 1 and lay it such that the edges of the end are justified with the low-pitch roof corner.
Roll out the roofing to the other end of the low-pitch roof. Mark the rolled roofing and snap a chalk line across the bottom of the roll to cut it in the same way you did in Step 1 with the first end. (Have a helper verify that the first end is justified before making marks and cutting the opposite end.)
Heat the back of the cut length of rolled roofing with a heat gun or blow torch and lay it in place. Do not step on the rolled roofing while the tar is setting, or the tar will seep out, creating ugly black marks on the roof.
Repeat Steps 1 through 3 for the second tier of rolled roofing. The second tier should overlap the first tier by 4 inches.
Repeat Step 5 until you reach the top of the roof and can no longer lay a whole width of rolled roofing.
Trim the last row of rolled roofing such that it is justified with the back of the roof. Heat the tar in place.