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How To Shingle A Roof Dormer

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If you have a roof dormer that isn't covered, you will want to shingle it for protection. A dormer is a roof extension that commonly ties in with the main roof and has three walls with a glass pane. You should be able to install shingles yourself provided you feel comfortable working from heights and have some DIY experience. Here are tips to shingle a roof dormer.

Prepare to Work

For this project, you need:

  • work gloves
  • ladder or scaffold
  • tape measure
  • utility knife
  • metal flashing
  • tin snips
  • hammer
  • galvanized roofing nails
  • galvanized flashing nails
  • heavy roof staples and staple gun
  • roof felt
  • roof tar
  • asphalt shingles

Set a ladder or scaffold in a safe place. Tie a safety harness opposite the working area for extra protection. If you use a ladder, get someone to hold it for you. Measure sides and ends of the dormer to determine how much flashing is needed.

Install the Flashing

Install the drip edge flashing at the valley (where the dormer meets the original roof). One edge of flashing should lay on the dormer and the other on the main roof with a one-fourth inch of an overhang over the roof eaves.

Nail the flashing in place on each side of the dormer; trim extra flashing with tin snips. Spread roof tar over the seams to seal.

Add the horizontal flashing in front of the dormer. Nail one side of the flashing to the dormer wall and the other side to the main roof, extending it slightly over the wall corner.

Use tin snips to cut a slit in the bottom of the flashing at the bend line, and fold it around the corner. Repeat the process for all sides.

Lay the Shingles

Unroll the roofing felt and staple it in place. When you come to a new row, overlap the new row by a half an inch to protect the roof from moisture.

Begin shingling at the bottom of the dormer. Use the utility knife to cut the bottom panels off the shingles.

Lay a shingle on the dormer corner and trim it to fit. Allow the adhesive strip to overhang on the drip edge flashing by one-fourth inch overhang. Hammer a nail in the shingle an inch below the slot, then add three more nails. Continue laying the first row of shingles.

Lay the next row of shingles with a slight overlap; placing the tabs on the adhesive strips on the bottom shingles. Snap a vertical chalk line to use a guide for placing additional rows on the other side

Proceed until you reach the top, and the lay the shingles in same manner down the other side. Shingle the dormer ridge last.

Shingles not only protect the roof dormer, but it will look better. If you don't trust your skill or the roof is seriously damaged, contact a roofer.