Asphalt shingles are a very common roofing material. If you have asphalt shingles and need to replace a few of them or are thinking about replacing your whole roof with asphalt shingles this article will teach you how to install asphalt shingles.
This instruction describes how to install asphalt shingles with basic 3 tab dimensions of 36 inches wide and 12 inches tall. All the roofing images and diagrams reflect these dimensions. When re-roofing building codes allow for up to 3 layers of asphalt shingles to be installed. This means you can install asphalt shingles over your existing asphalt shingles as long as there are not more than 3 layers. Figuring out how to shingle a roof is easy so lets get started....
In this article, you will find information about:
tools and materials
What is exposure?: Shingles exposure is the amount of roofing shingle that is showing after it is installed and other shingles are covering it up. 3 tab shingles are 12 inches high. The bottom 5 inches is exposed and the top 7 inches are covered by the next higher course of shingles, So it has 5 inches exposure.
What are courses?: A course is one row of shingles. When installing asphalt shingles the courses are staggered so that if the water makes it down the joint between the ends of shingles that it will fall onto another shingle and not a joint. It takes 6 courses to go thru all the steps because 6 inches goes into 36 inches, the width of a shingle, 6 times.
What is step flashing?: Step flashing prevents water from running off the end of a roof shingle where the shingle meets a wall or chimney and thereby prevents leaks at this roof to wall connection. Step flashing is used where a roof meets a wall or other vertical surface. Every shingle gets its own step flashing piece. The finished asphalt shingle and step flashing installation looks like steps going up the vertical surface. Step flashing is a very important part of learning how to shingle a roof.
How to cut an asphalt shingle: Cutting a shingle is similar to cutting drywall or tile underlayment. You simply score the back side, the smooth side, and then bend the shingle on the score mark. With a hand on each side of the score mark you bend the shingle back and forth until it breaks on the score line. You should change your knife blade frequently to get a good cut in the shingles. The article How To Cut Asphalt Shingles has more detailed information on cutting asphalt shingles.
Weather: When installing asphalt shingles in extreme temperatures it is important to remember that when it is hot asphalt shingles become gooey and can be damaged by walking on them. When it is cold the shingles are hard to work with because they are well, hard. They are hard to cut and hard to get to lay flat. Using a nail gun in very cold weather can shatter a shingle.
The first step in installing asphalt shingles is to put the drip edge on the eve of the roof. You will put it on the eve of the roof then put on the building paper over the drip edge and then put the drip edge over the building paper on the rakes of the roof.
Eve Install: Put the drip edge on the eve edge of the roof by holding it up to the edge and putting a nail every 24 inches. Do not install drip edge on the gables at this time, (the rake) of the roof, you will do that after the underlayment is installed.
Waterproofing membrane is a very thick material that forms a waterproof barrier in areas that are prone to leak. It comes in several forms and is either sticky back or non sticky back. I prefer the bituminous sticky back membrane because it stays where it is put and sticks to itself when it is layered for larger areas, it also does not need fasteners to install it which is good because you are not putting holes in the membrane that is protecting the most leak prone areas of the roof. Install the membrane in valleys by running the 36" wide material straight up the valley. Install it in damming areas like where a wall and valleys that are close to each other or in roof pitch transitions.
If you use a non sticky back membrane make sure to step on the center line of the valley to get it fully in contact with the wood valley and then attach the outer edges with fasteners about an inch from the edges.
Underlayment has traditionally been made from felt paper soaked in tar, tar paper. It is still widely used, if you use it then use 30 lb. roof felt. It's heavier weight makes for a longer lasting higher quality roof. Roofing felt is held to the roof using a nail or staple with a plastic cap that keeps the nail from ripping the building paper. Other products are made from reinforced plastic sheeting, these materials are more durable than asphalt felt but cost a bit more. If you are in a situation where you will not be able to install the asphalt shingles immediately after the underlayment is put down you should consider using a plastic reinforced sheeting because it will not break down as fast as building paper.
Safety: Do not walk on the underlayment if it is not fully nailed off. It may feel stable but will quickly give way and send you sliding down the roof. Be careful when it is nailed off, it is paper and can rip and cause you to fall.
Fasteners: Install the underlayment with Plastic Cap nails. Regular nail heads will tear thru the underlayment. Put a plastic cap nail every 24 inches horizontally and three nails vertically on the underlayment so that it is less likely to rip when you walk on it or a strong wind tries to lift it. The first row is the hardest because you need to stand above it to nail it on. After the first row is on you can walk on it to install the next row of underlayment.
First Row: Start at the eve and one end of the roof and roll out about 5 feet of building paper. Square up the underlayment with the drip edge and install the plastic cap nails to hold the paper in place. Install the underlayment so that it goes on top of the drip edge but not over the edge of the drip edge, hold it back about 1/4" from the edge.
Successive Rows: Continue up the roof and overlap on top of the lower row by 2". There is a mark on underlayment material at 2" from the edges to help guide the successive rows. Cap the ridge after you have done both sides of the roof.
Rake Install: After the underlayment is installed on the whole roof make sure the ends are trimmed to the fascia on the rakes and then install the drip edge on top of the underlayment on the rakes of the roof. Use a nail every 24 inches. Put the nails on the top side, the roof side.
step 6 Layout Control Lines On The Underlayment
Snap horizontal and vertical lines on the roof to keep courses straight. Start with the first line 2 courses up and then do about every 3 feet from there up the roof. Don't worry about hitting an exact course location, you can eyeball the distance from the closest line.
The starter course is the first course of shingles at the eve. It is a course of shingles that have the tabs cut off. You can either buy a "starter" course shingle that has the tabs cut off or you can cut the tabs off the shingle with a utility knife. The first Starter shingle needs to have 6 inches cut off its end it to create a staggered pattern that does not line up with the full size shingle that will be placed on top of it. Turn the starter shingle upside down so that the sticky asphalt strip can stick to the underlayment just above the drip edge. Install the edge of the starter strip 3/8" over the edge of the drip edge. Install five fasteners in each shingle up 3 to 4 inches from the eve.
The first roofing course goes on top of the starter course. It fully covers the starter course. To start you will install a full asphalt shingle where the rake end and the eve meet. Fasten it according to the instructions on the shingle packaging, usually 5 nails, one on each end, one in the center and one in between the first three. Start with a full shingle at the same rake end that you laid the first starter strip.
Install second thru sixth courses by cutting 6 inches off the end of the first shingle and installing them 5 inches from the bottom of the first course.
step 10 Install The Seventh Course
Install the seventh course just like the first course by using a full shingle, overhang it 3/8" over the rake end and 5" up from the bottom of the course below.
step 11 Install The Valleys
There are two ways of applying shingles to a valley, Closed-cut and Weaved. This article will teach you how to install a Closed-cut valley, as part of how to shingle a roof, which I believe is the better of the two ways to construct a valley because when the shingles expand and contract with the seasons the two sides of the Closed-Cut valley move independently and do not pull off the roof.
Roof One Side Of The Valley: Fully install the roofing on one side of the valley. Run all the shingle courses past the center line of the valley and let the shingle run up the other roof by at least 12 inches. Install a nail at least 6 inches from the valley, (no nails in the valley).
After the first roof is shingled and all the shingles run up onto the other roof at least 12 inches then mark a chalk line 2 inches from the center line on the un shingled roof. This line is where you will cut the second roof shingles to.
Begin running the shingles on the second roof. When you get to the chalk line on the valley you will cut the shingles on the second roof to the chalk line. Be careful to not cut the first roofs shingles. Always nail at least 6 inches from the valley. If you have a shingle piece that is too small to nail in the valley you can use roofing cement to glue it on.
The ridge cap is installed using a pre cut ridge cap shingle or by cutting up a regular three tab shingle into 3 pieces, 12" x 12".
Ridge Only: Bend the shingle over the ridge and put a nail on each side in the same location from the end as you did with the regular courses, about 5 5/8" up from the exposed end and 1 inch from the side edges. Continue down the ridge until the other end of the ridge where you will cover the last shingle by turning a shingle around and putting it on top of the last shingle.
Hips: When working on hips you need to do the hip first and then do the ridge. Start at the eve and work up to the ridge, then apply caps on the ridge. Use 5" exposure, just like the regular shingle courses. The ridge is started on the end that is opposite the prevailing winds to reduce the chance of catching wind.
For instructions on how to install step flashing see the article How To Install Step Flashing.