How to Apply a Modified Bitumen

Prepare the Roof Deck

• 1

  Scrap the roof decking to remove all components of the old roof, including the shingles and underlay. Strip the roof down to the wood sheathing. Inspect the roof deck for any damage and re-nail any protruding nails. This is a good time to re-nail the roof deck with 8d ring shank nails to improve the deck's connection to the roof truss underneath.

• 2

  Sweep the deck so it is clear of all debris.

• 3

  Measure the roof deck to determine the amount of modified bitumen you will need for the project. To seal the entire surface, measure the roof's length and width to calculate the amount of square footage of modified bitumen you will need. To seal only the seams, measure the length of each seam and total each measurement to figure how many linear feet of material you will need.

• 4

  Measure and cut the self-adhering modified bitumen membrane into pre-measured lengths based on the measurements used to determine the amount of material needed. Apply the primer to the first area to be covered. Apply the primer to the entire surface area over which the membrane will be applied.

• 5

  Take a length of the pre-cut material and start at a front bottom corner of the roof or end of a seam. With the adhesive side of the membrane facing down toward the roof deck, peel back a few inches of the adhesive covering. Seal the first few inches of the membrane to the roof deck and slowly work your way down the length, removing a few inches of adhesive covering at a time and sealing those few inches as you move along. Continue sealing the material to the deck until you reach the end. Repeat this procedure until the entire roof deck or each seam is completely covered. Use a knife to cut the material to fit around vent pipes.