Parts of a Roof: Underlayment and Edging

In our last post we discussed your home’s roof deck. Once your roof deck is solid and ready to go, there are a few more steps before the shingles go on.

WHAT IS UNDERLAYMENT?

Underlayment, simply enough, is what goes under your shingles. It’s an added layer of protection. It’s moisture-resistant or moisture-proof, so it protects from condensation and other forms of moisture that shingles alone won’t prevent.

There are a few different types of underlayment to be aware of if your home is being reroofed.

TAR PAPER

Asphalt-saturated felt paper, or “tar paper” used to be the standard underlayment on most homes. This heavy, stick black product covered the roofs of homes across America and the world for a long time. Most of the roofs we tear off still have tar paper under the shingles.

In recent years, tar paper has been almost completely replaced by newer, longer lasting, and more waterproof materials.

SYNTHETIC UNDERLAYMENT

Modern underlayment materials resist tearing, and unlike asphalt underlayments, don’t get brittle and break down over time. They’re also safer for installers, providing much better traction.

They also lay flatter than a typical tar paper underlayment, which means the shingles will lay flatter and look better, too.

In most cases, you’ll want to make sure your roofing contractor is using a modern underlayment, not tar paper.

ICE AND WATER SHIELD

Ice and water shield is added protection for vulnerable areas of your roof. It adheres to the roof deck, guaranteeing a seal against the elements.

We use it at the eaves, as the first run of underlayment, and in the valleys. It goes around any pipes, vents, or skylights on the roof, as well.

WHAT IS DRIP EDGE?

Drip edge is a strip of metal that transitions water from the roof into the gutter, or down the fascia. Without the correct drip edge, water will rot the edges of your decking, and run behind your gutters.

TALKING ABOUT UNDERLAYMENT AND DRIP EDGE

If you’re getting your roof replaced – make sure you know what’s going on with your underlayment and edging. You don’t want to cut corners here, and you want to find a contractor who takes good care of all the parts of a roof, not just the shingles.