What Is Roofing Underlayment?
Roofing underlayment is the waterproof barrier installed directly on your roof deck before the shingles or metal panels go on top. It's your roof's second line of defense — if wind-driven rain gets under your shingles during a Houston hurricane, the underlayment keeps water out of your home. It also protects the deck during installation and prevents condensation from collecting on the sheathing.
Types of Roofing Underlayment
Synthetic Underlayment
The current industry standard. Made from woven polypropylene, synthetic underlayment is lighter, stronger, and more tear-resistant than felt. It resists UV exposure for weeks if there's a delay between deck and shingle installation. This is what RISE Roofing installs on every project. Common products: GAF FeltBuster, CertainTeed DiamondDeck, Owens Corning ProArmor.
Felt Underlayment (Tar Paper)
#30 felt is the traditional option. Less expensive than synthetic but tears easily, absorbs water, wrinkles when wet, and degrades quickly under UV exposure. Still code-compliant but increasingly replaced by synthetic on quality installations.
Peel-and-Stick (Self-Adhering)
Rubberized asphalt membrane that bonds directly to the deck, creating a completely waterproof seal even around nail penetrations. Used at valleys, eaves, penetrations, and rake edges. Full-deck peel-and-stick provides ultimate protection and can earn insurance premium credits in Texas high-wind zones.
Underlayment by Roofing Material
- Asphalt shingles: Synthetic standard; peel-and-stick at valleys and penetrations.
- Standing seam metal: High-temperature rated synthetic required — metal surfaces can exceed 180°F.
- Tile and stone-coated steel: Heavier underlayment or double-layer application typical.
- Flat roofs: Typically replaced by the membrane system itself (TPO, mod-bit, etc.).
Cost of Roofing Underlayment in 2026
| Underlayment Type | Installed Cost / sq ft | 2,000 sq ft Home |
|---|---|---|
| #15 felt | $0.15–$0.25 | $400–$650 |
| #30 felt | $0.25–$0.40 | $650–$1,000 |
| Synthetic (standard) | $0.35–$0.65 | $900–$1,700 |
| Peel-and-stick (full deck) | $1.00–$2.50 | $2,600–$6,500 |
The difference between felt and synthetic for a 2,000 sqft roof is roughly $200–$600 — a small price for a significant performance upgrade, especially in Houston's storm-prone environment. Use our Roof Cost Calculator for complete project estimates including underlayment.
Building Code Requirements in Houston
Texas residential code requires a minimum #15 felt or equivalent synthetic underlayment under all asphalt shingles. Wind zones (which include much of the Houston area) may require additional ice-and-water shield at eaves. RISE Roofing installs to code minimums plus our own quality standards on every project.