Shingles get all the attention, but the underlayment beneath them is your roof's real last line of defense against Florida rain. Here's what it is and why the type matters.
By Tyler Wisdom | Roofing | 2026-04-08 | 7 min read
roof underlayment · synthetic underlayment · peel and stick · roof installation · tampa roofing
When you picture a roof, you picture shingles or tile. But underneath that visible layer is the underlayment — a barrier laid directly over the roof decking before the shingles go on. It's invisible once the roof is finished, and it's the layer most homeowners never think about. In Florida, it's also one of the most important.
Shingles are your roof's first defense, but they aren't perfectly waterproof — wind-driven rain can get past them, especially in a Tampa Bay storm. Underlayment is the secondary barrier that keeps that water off your wood decking and out of your home. It also protects the decking during installation and adds a layer of defense if shingles are blown off in a hurricane.
The old standard — black 'tar paper' in 15 lb or 30 lb weights. It's the cheapest option and still used, but it tears more easily, can wrinkle in heat, and absorbs moisture over time. In Florida's sun and humidity, felt is increasingly seen as the bare minimum.
Woven polypropylene or polyester — lightweight, tear-resistant, and far more durable than felt. It doesn't absorb water, resists wrinkling in heat, and holds up to UV exposure longer during installation. For most Tampa Bay roofs, synthetic is the smart baseline choice.
A rubberized, fully-adhered membrane that bonds directly to the decking and seals around every nail. This is the premium option and the gold standard for Florida's wind and rain — it provides true waterproofing even if shingles are lost. It's especially valuable in high-wind zones and on low-slope sections.
Many of the best Tampa Bay roof systems use a hybrid approach: peel-and-stick membrane in the most vulnerable areas (eaves, valleys, around penetrations, and low-slope sections) and high-quality synthetic across the main field. You get maximum protection where it matters most without the cost of covering the entire roof in membrane.
Underlayment is the unsung hero of a Florida roof — the waterproof layer that keeps wind-driven rain out when shingles can't. Skimping here to save a little money is a false economy in Tampa Bay. Insist on quality synthetic at minimum, with peel-and-stick membrane in the vulnerable areas, and your roof will protect your home far better through every storm season.
Gladiator Exteriors builds roof systems with quality underlayment matched to Florida's climate and code. Call (813) 419-2656 for a free inspection and a quote that spells out exactly what goes under your shingles. Veteran-owned, licensed Florida contractor CCC1337377.
Call (813) 419-2656 for your free estimate.