How to Shingle a Roof Dormer

What You'll Need
Extension ladder
Sheet metal flashing
Drip edges
Asphalt shingles
Chalk line
Tape measure
Roofing nails
Roofing hammer
Roofing tar
Roof felt
Staple gun/staples

Building a roof dormer is one way to add a little more room, or light, into an upstairs area without having to do an extensive, and costly, remodeling project. Dormers are great for an office, bedroom, sitting area or just more space in your attic, or to add character to your home. Once the roof dormer is built, you will need to go through the process of shingling it for protection and an finished look. Here are the steps to take for shingling your roof dormer.

Step 1 - Install Flashing and Drip Edge

You will need to install metal flashing along the valley where the dormer meets the original roof. The flashing will go under the shingles on he original roof so you will need to pry up a corner of each one. Nail it to the roof with roofing nails and run tar down the length of the seams. The drip edge is another piece of water protection that goes along the eaves of the dormer. It should overhang about 1/4 inch so water can run off without contacting the underlayment.

Step 2 - Lay Down Underlayment Felt

Using a felt underlayment, roll it out along the roof. Start at the bottom of the roof and work your way up. Secure the underlayment with heavy duty staples. Overlap each successive row by 1/2 inch for protection against water and ice build up. 

Step 3 - Install Starter Shingle Row

The starter shingles are placed on the bottom row of the roof dormer or completing a seal against water and ice. Cut off the bottom panels of the shingle with a utility knife. Pace a shingle at the corner of the dormer and cut it to fit according to the angle of the dormer and original roof. The adhesive strip should overhang the drip edge by about 1/4 inch. Nail to the roof with roofing nails. Continue laying out starter row until you reach the end. Butt each shingle end to end with no overlap. 

Step 4 - Start Installing Shingles

Once the starter row is done, you can then begin shingling the roof. Start in the corner and place the first shingle on top of the starter row. The adhesive strip should contact the bottom of the shingle for a seal to be made. Nail it to the roof with four roofing nails. Continue with this next row until you reach the end of the dormer.

Step 5 - Continue Shingling Roof Dormer

Start the next row with the bottom tabs of the shingle on top of the adhesive strip of the bottom shingle. This should give you about 6 inches of overhang. String out a chalk line and snap it as a reference for the rest of the row. Continue laying the shingles in the same manner until you reach the top of the dormer. Repeat the process on other side of dormer.

Step 6 - Shingle Ridge Line

The top of the roof dormer is shingled across the ridge line. Start at the outward edge and lay a shingle across the ridge and nail with roofing nails. Continue shingling in this manner, by overlapping the next shingle, until you reach the valley.