Cedar shingles are a popular material for rooftops. Cedar's natural durability, its resistance to rot, and its attractiveness make it an excellent choice for covering a roof. Cedar shingles are applied to a rooftop in a series of overlapping courses. The overlapping pattern directs water down the sloped rooftop and into the rain gutters. Properly installed cedar shingles will keep the underlying framework of a house from being damaged by water. Cedar shingles should be applied over a layer of roofing felt to increase the water-resistant properties of the rooftop.
Install wooden furring strips to the roof deck. Run these boards horizontally along the rooftop, from one end to the other. On the lower 2 feet of the roof, closest to the roof eave, butt the furring strips together to create solid sheathing. Beyond the initial 2 feet space the furring strips about 4 inches apart. Cut these furring strips to length with a circular saw and fasten them to the roof deck with roofing nails driven every 12 to 16 inches.
Start at the base of the roof and roll out a row of roofing felt. Extend the felt from one side of the roof to the other and tack it in place with a few nails to keep it from blowing away while you work.
Lay your first course of shingles. Start in one corner and position the shingle so it hangs 1½ inches over the fascia and 1 inch over the rake or gable. Work across the roof and fasten each shingle with two roofing nails. Drive the nails ¾ inch from each shingle edge and 1 inch above the exposure line, or the portion of the shingle face that will be visible after the next course is applied over the top of it. Shingles are typically tapered, with a thin end and a thick end. The thin end is the top and the thicker end the base. Make sure the thin end points toward the roof's peak and the thicker end points down. Space the shingles about 1/8 inch apart.
After laying each shingle course, fasten an 18-inch-wide layer of roofing felt over the top portion of the shingle and extending onto the roof sheathing.
On the first course, fasten a double layer of shingles. Install a layer of shingles directly over the top of the first course. Stagger the seams between the layers.
Where necessary, trim your shingles to size with a sharp utility knife. For angled cuts, use a mitre-box saw.
Use a tape measure and pencil to mark the baseline of your second course of shingles. The amount of exposure will vary depending on the size of shingle you are installing. Consult the manufacturer's instructions regarding proper exposure. Use the tape measure and a chalk line to snap this guide line across the first course of shingles.
Fasten your second course of shingles. Position the base of the shingles on the chalk line you snapped. Stagger the seams from one course to the next to increase the overall water-resistance. Continue this process until you have installed shingles from the base of the roof to the peak. Once you've finished one section of the roof, repeat the same process on the remaining sections.
Install a thin strip of roofing felt along the roof peak. Then install hip and ridge units along the roof peak. These specialised pieces are composed of two shingles cut at angles and nailed together to create a single, cohesive unit. Overlap the hip and ridge units according to the manufacturer's instructions, and nail each unit with two roofing nails driven into the portion of the hip and ridge unit that will be overlapped.
Take great care when working on any rooftop. Falls can lead to serious injury and even death. Wear a safety harness to prevent falling and being injured.