TL;DR: Ice and water shield is a self-adhering, rubberized asphalt membrane installed under your roofing material to create a waterproof seal on the deck. Florida roofs don’t face ice dams, but they face something equally dangerous: hurricane-force wind-driven rain. The Florida Building Code requires this membrane in specific high-risk areas on every new or replacement roof, and many Central Florida and Space Coast contractors — including Thomas Roofing & Repair — recommend broader coverage for maximum protection.
Most homeowners hear ‘ice and water shield’ and picture a cabin buried in snow. Understandable — the name sounds like something from Minnesota, not Orlando. But this product is just as critical, arguably more critical, on a Florida roof.
Here is everything you need to know: what it is, how it works, where Florida code requires it, and how to tell whether your roof has it.
What Is Ice and Water Shield?
Ice and water shield is a self-adhesive, waterproof roofing underlayment membrane made from rubberized asphalt. It is installed directly on the roof deck — underneath shingles, tile, or metal panels — before any other roofing material goes down.
You may also hear it called a self-adhered membrane, peel-and-stick underlayment, or an ice and water protector. They all refer to the same class of product.
What It’s Made Of
According to IKO, a major roofing manufacturer, ice and water protectors are made with polymer-modified bitumen. The adhesive back surface bonds to the roof deck, creating a superior underlayment in areas prone to severe storms.
The product comes in rolls — typically 36 inches wide — with a release film on the sticky side that peels away during installation. Once applied, the membrane bonds tightly to the plywood or OSB sheathing and forms a fully waterproof seal.
The Self-Sealing Nail Feature
This is the detail that separates ice and water shield from ordinary felt or synthetic underlayment. When nails or screws penetrate the membrane, the rubberized material compresses around the fastener and seals the hole. Standard felt paper cannot do this — water can travel down a nail shaft and reach the deck.
As CertainTeed notes about its Vycor® Ice & Water Shield, the rubberized asphalt layer seals around fasteners, resisting leakage caused by both ice-dam water backup and wind-driven rain.
How Does It Work?
Ice and water shield works on two principles: full adhesion and self-sealing.
- Full adhesion means the membrane sticks directly to the deck — it cannot be lifted or blown away the way loose-laid felt can.
- Self-sealing means nail and screw penetrations close themselves, so water cannot sneak through fastener holes.
Together, these two properties create what roofing professionals call a secondary water barrier — a last line of defense if the primary roofing material (shingles, tile, metal) is compromised.
It is installed as the first layer on the deck, before any felt or synthetic underlayment. Sections overlap by at least 6 inches to eliminate gaps, and it is placed under flashing at chimneys, skylights, and wall junctions to direct water away from those transitions.
Why Florida Roofs Need It (It’s Not About Ice)
In northern climates, the primary threat is ice dams — snow melt that refreezes at the eave and backs water up under shingles. Florida obviously does not have that problem.
What Florida does have is wind-driven rain, and it is every bit as destructive.
During hurricanes and tropical storms, wind can push rainwater sideways and even upward under shingles, tile, and metal panels. When sustained winds exceed 60 mph, rain strikes at steep angles — sometimes nearly parallel to the roof surface — forcing water through shingle edges, nail lines, and roof valleys. Standard felt paper has minimal tear resistance and can shred within minutes of direct wind exposure. Once felt is gone, the bare deck is exposed.
Ice and water shield prevents this. Because it bonds directly to the deck and seals around every fastener, it stops wind-driven rain from reaching the sheathing even if shingles are partially lifted or lost. As IKO explains, the membrane ‘fully adhered to the roof deck, greatly lessens the chance of the wind-driven rain infiltrating the roof surface and causing a leak.’
There is also a coverage gap worth knowing: FEMA notes that the National Flood Insurance Program does not cover wind-driven rain damage — meaning a standard flood policy will not pay for interior water damage caused by rain entering through a storm-damaged roof. Your homeowner’s insurance must cover it, and carriers are increasingly scrutinizing roof condition and construction quality at renewal time. A properly installed secondary water barrier strengthens your position.
Where Does the Florida Building Code Require It?
The 2023 Florida Building Code (FBC), 8th Edition addresses self-adhered polymer-modified bitumen underlayment — the technical category ice and water shield falls under — in several roofing contexts. Requirements vary by wind zone and roof type, but at minimum, the FBC requires the membrane in these high-risk areas on most residential roofs:
- Roof valleys — Self-adhering polymer modified bitumen underlayment complying with ASTM D1970, not less than 36 inches wide, is explicitly permitted (and commonly required) as valley lining under the FBC.
- Deck joints — A minimum 3¾-inch-wide strip of self-adhering polymer-modified bitumen membrane (ASTM D1970) must be applied over all joints in the roof decking as a secondary water barrier.
- Roof penetrations — Around chimneys, skylights, plumbing vents, and HVAC curbs, self-adhered membrane is required under flashing assemblies.
- Eave edges — Self-adhered underlayment must extend from the eave edge a minimum of 24 inches past the interior wall line.
In the High Velocity Hurricane Zone (HVHZ) — Miami-Dade and Broward counties — the requirements are even more stringent, with self-adhered membrane required across a greater portion of the deck. For tile roofs statewide, the FRSA/TRI Florida High Wind Concrete and Clay Roof Tile Installation Manual specifies self-adhered modified bitumen underlayment as part of the required underlayment assembly.
For Central Florida (Orange, Seminole, Osceola, Polk, Lake counties), Volusia County, and Brevard County — the areas Thomas Roofing & Repair serves — the standard FBC requirements apply. Many contractors, including our team, recommend going beyond the minimums on valleys and eaves given the region’s hurricane exposure and intense summer storm activity.
Where Is It Installed on a Typical Florida Roof?
Even where full-deck coverage is not required, ice and water shield should be installed at every location where water has a path to concentrate or back up:
- Eaves — The lowest edge of the roof, where wind-driven rain first contacts the structure
- Valleys — Where two roof slopes meet; water volume is highest here
- Around all penetrations — Chimneys, skylights, pipe boots, exhaust vents, HVAC equipment
- Rake edges — The sloped edges at the gable ends
- Wall-to-roof transitions — Where a vertical wall meets the roof plane
- Low-slope sections — Any area with a pitch below 2:12 where water drains slowly
It works with all common Florida roof types: asphalt shingles, concrete and clay tile, and standing-seam or metal shingle roofs.
To understand how ice and water shield fits within the full underlayment system, see our guide: What Is Roofing Underlayment and Why It Matters in Florida’s Climate.
Pros and Cons of Ice and Water Shield
Advantages
- True waterproofing — Unlike felt, which is only water-resistant, a properly adhered membrane is fully waterproof
- Self-seals around fasteners — Eliminates a common leak path that felt and synthetic underlayments cannot address
- Wind-driven rain protection — Stays adhered even if shingles are partially lifted during a storm
- Meets FBC secondary water barrier requirements — Satisfies code in both standard and HVHZ wind zones
- Compatible with all roof types — Works under shingles, tile, metal, and slate
- Supports insurance and manufacturer warranties — Many shingle manufacturer warranties require or recommend it at valleys and eaves
Limitations to Know
- Heat sensitivity during installation — In Florida’s summer heat, the membrane becomes very pliable. Errors in alignment are extremely difficult to correct once the adhesive contacts the deck, which is why professional installation matters.
- Vapor barrier effect — Full-deck coverage creates a very tight vapor barrier. Attic ventilation must be properly designed to prevent moisture buildup and wood rot. Your roofer should evaluate ventilation as part of any full-coverage installation. (See our guide on roof soffit ventilation for more on this.)
- Cost — Ice and water shield costs more per square foot than standard felt or synthetic underlayment. A roll covering roughly 200–225 square feet typically runs $90–$150, though full-deck coverage significantly increases material cost.
- Cannot be left exposed — The membrane must be covered by the finish roofing material; it degrades with prolonged UV exposure.
Does Your Current Roof Have Ice and Water Shield?
If your roof was installed before the Florida Building Code began requiring secondary water barriers more broadly, or if it was installed by a contractor who cut corners on underlayment, you may not have adequate coverage — or any at all.
You cannot see ice and water shield from the ground. A qualified roof inspection can identify whether the correct underlayment was installed, whether the existing membrane is properly lapped and sealed, and whether your roof’s vulnerable zones are adequately protected. Thomas Roofing & Repair’s team includes HAAG Certified Inspectors who perform thorough roof evaluations across Orange, Seminole, Osceola, Polk, Lake, Volusia, and Brevard counties.
A roof replacement is also the right time to verify that your drip edge, underlayment system, and self-adhered membrane all work together correctly. Our article What Is a Drip Edge and Why Does Every Florida Roof Need One? covers how the drip edge and underlayment interface — a detail that directly affects how ice and water shield performs at the eave.
The Bottom Line for Florida Homeowners
Ice and water shield is not a northern luxury. On a Central Florida or Space Coast roof, it is a hurricane-season necessity. It is the layer your roof falls back on when 100-mph wind pushes rain uphill under your shingles, when a pop-up storm hammers a valley with five inches of rain in an hour, or when a named storm peels back a course of shingles and leaves your deck temporarily exposed.
The Florida Building Code sets a floor, not a ceiling. At Thomas Roofing & Repair, we install to manufacturer-compliant practices and current FBC requirements — and we discuss coverage options openly so you can make the right decision for your home and budget.
If you want to know whether your roof’s secondary water barrier is up to the job, request a roof inspection from our team. We serve homeowners across Central Florida, Volusia County, and Brevard County — with bilingual English and Spanish staff and flexible financing available.
Recommended Reads
- What Is a Drip Edge and Why Does Every Florida Roof Need One?
- What Is Roofing Underlayment and Why It Matters in Florida’s Climate
- What Is Roof Fascia — And What Happens When It Fails?