Underlayment for Hurricane-Resistant Metal Roof Assemblies
MRM Tornado Underlayment is the layer that backs up the panel when the wind is doing its worst.
Wind rating gets the headline, but a storm-ready roof is built in layers. Underneath the panel, MRM Tornado Underlayment is sealed to the deck, doing five separate jobs long before the first named storm of the season.
What Backs Up the Panel
Self-sealing around fasteners
Fewer points where wind-driven rain can find a way in.
Secondary water barrier
Helps keep water off the deck if the panel above it is damaged, until repairs are made.
Fastener-Level Sealing
Self-adhesive membrane seals around every fastener the panel is screwed into.
A Backup Plan for the Deck
If the panel above is damaged, this layer helps limit water reaching the deck. Wind resistance comes from the panel and its attachment, not the underlayment.
Class A Fire Rated
Class A fire resistance as part of a tested roof assembly.
Radiant Energy Barrier
Reflects heat on every ordinary day between storms.
Sound Barrier
Quiets the sound of wind-driven rain and hail against the panel.
Installed Before the Wind Rating Even Applies
Self-adhered to the deck, sealed around every fastener, underneath the panel that carries the wind rating. It's part of the same system, installed as one continuous build, not bolted on separately. The wind rating belongs to the tested panel assembly; the underlayment's job is water protection.
Wind Rating and Water Protection Are Two Different Jobs
The wind rating: the panel system
A metal roof's uplift resistance is established by testing the panel, its clips or fasteners and the deck attachment together, under standards such as UL 580, UL 1897 or, in the High-Velocity Hurricane Zone, TAS 125. The design pressure your roof needs is calculated from the building's location, height and exposure.
The water protection: the underlayment
The underlayment doesn't hold the roof down. Its job is keeping water off the deck: sealing around fasteners and catching wind-driven rain that gets under the panels. If panels are lost in a storm, it can limit water entry for a while, but it isn't designed to act as the roof.
When comparing quotes, ask for the Florida Product Approval or Miami-Dade NOA numbers for the exact panel system and underlayment being installed.
Certifications That Belong on Any Storm-Ready Quote
- Miami-Dade County Approved
- Class A Fire Resistance
- Meets or exceeds ASTM D1970
- Standard 20-Year Limited Warranty
- Manufactured in the USA
- Paired system approval with MRM Tornado Steel & Aluminum Roof Panels (FL-approved)
All Four Install the Same Way: Sealed to the Deck
Every product in the lineup is self-adhered before the panel goes on.
MRM Tornado Radiant Barrier SWR 5000 FR
Reflective face, self-adhered, sealed around fasteners.
MRM Tornado Radiant Barrier SWR 2000 FR
The lighter reflective version of the same sealed install.
MRM Tornado Duo Barrier 1500 HT
Duo-layer, self-adhered directly to the deck.
MRM Tornado White SBS Cap Sheet 4000 FR
Mineral-coated, self-adhered cap sheet option.
Getting Storm-Ready, Layer by Layer
Inspect the deck
Confirm it's ready for a fully sealed underlayment install.
Seal the deck
Self-adhered underlayment, sealed around every fastener.
Install the wind-rated panel
Completing the system on top of the sealed deck.
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