Homeowner guide
Roof Underlayment and Drip Edge Explained
Shingles get the attention, but the parts under them protect the house too. Here is what underlayment, ice and water protection and drip edge do and what to ask about in an estimate.
The short answer: Underlayment is a protective layer installed over the roof deck under the shingles. Ice and water protection is a self-sealing membrane used in vulnerable areas like eaves and valleys. Drip edge is metal along the roof edges that directs water into the gutters. Ask each bid to name the type used.
The short version
Shingles are the outer layer. Underlayment, ice and water protection, flashing and drip edge form the backup system that keeps water out when wind pushes rain under the shingles or ice backs up at the eaves. These parts are hidden once the roof is done, so they are worth asking about before you sign.
What underlayment does
Underlayment sits between the deck and the shingles. It adds a secondary barrier against water and helps protect the deck during and after installation. Common types include traditional felt and synthetic underlayment. Synthetic products are often lighter and tear-resistant, but the best choice depends on the roof and the manufacturer’s requirements. Ask which product is quoted and whether it is required for the shingle warranty.
Ice and water protection
Ice and water protection is a self-sealing membrane that bonds to the deck and seals around nails. Roofers commonly use it along the eaves, in valleys and around penetrations, where leaks often start. In Indiana, where ice dams can push water under shingles, this can matter. See ice dams in Indiana.
Where and how much is used varies. Model building codes and manufacturers have rules, and local codes can differ, so ask what your bid includes and why.
Drip edge
Drip edge is metal flashing installed along the eaves and rakes. It directs water into the gutter and away from the fascia and deck edge. Many building codes call for it on shingled roofs, and local rules vary, so ask your contractor to confirm what applies at your address. See roof permits in Indianapolis.
Flashing and ventilation
Flashing seals joints around chimneys, walls, vents and skylights, and it is a common leak source. Ventilation keeps the attic dry and helps against ice dams. See chimney flashing repair and attic ventilation in Indiana.
What to ask in an estimate
- What underlayment brand and type are you installing
- Where will you use ice and water protection
- Is drip edge included along eaves and rakes
- Will flashing be replaced or reused
- What is the ventilation plan
Our roofing estimates explained and roof replacement process show where these items fit.
Underlayment and drip edge questions
Do I need underlayment under new shingles?
Shingle manufacturers and building codes generally call for it. Ask your roofer what is included and what your shingle warranty requires.
What is the difference between felt and synthetic underlayment?
Felt is the traditional product. Synthetic underlayment is typically lighter and more tear-resistant. The right choice depends on the roof and manufacturer requirements.
Where is ice and water shield used?
Commonly along eaves, in valleys and around penetrations. Ask where your roofer plans to use it.
Is drip edge required?
Many codes call for it, and local rules vary. Ask your contractor to confirm what applies to your address.
Can I see the underlayment before the shingles go on?
Often yes if you are home during the job. Ask your roofer to photograph key stages.
Related:
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Roofing contractor serving Indianapolis, Indiana and the surrounding suburbs.
(317) 555-0142
123 Main Street, Indianapolis, IN 46204
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