Underlayment Options for Standing Seam Metal Roofs
MRM Tornado Underlayment, chosen to match the standing seam panel above it.
Hidden fasteners and clean architectural lines are only half the standing seam story. Underneath, MRM Tornado Underlayment does five separate jobs so that premium finish stays uncompromised.
Why Premium Panels Get a Premium Underlayment
Reflective face
The aluminum-faced rolls add a reflective layer under a standing seam finish; how much heat they block depends on the roof assembly and attic ventilation.
Clean seal
A fully self-adhered layer bonds to the deck, which helps keep it from shifting or wrinkling under the seams when installed on a clean, dry deck.
A Reflective Match for the Panel Above
The aluminum-faced options reflect radiant heat under the panel; actual performance depends on the full roof assembly.
Class A Fire Rated
Class A fire resistance as part of a tested roof assembly.
A Seal That Doesn't Interrupt Clean Lines
Installed correctly, the self-adhesive membrane lays flat, so it is less likely to telegraph through hidden-fastener seams.
Secondary Water Barrier
Backs up a system that relies on unbroken seams, not exposed fasteners.
Sound Barrier
Keeps a premium roof from sounding like a drum during Florida downpours.
The Pairing Most Often Chosen With Standing Seam
The aluminum-faced radiant barrier options are the most common pairing with standing seam.
MRM Tornado Radiant Barrier SWR 5000 FR
Our most common standing seam pairing, full reflective face.
MRM Tornado Radiant Barrier SWR 2000 FR
A lighter reflective option for smaller standing seam runs.
MRM Tornado Duo Barrier 1500 HT
Available where a duo-layer barrier is preferred over a reflective face.
MRM Tornado White SBS Cap Sheet 4000 FR
Mineral-coated option, less common under standing seam but available.
A Clean Deck for a Clean Roofline
Self-adhered to the deck before the standing seam panels are formed into place. Because standing seam relies on clean, unbroken lines, the deck below has to be sealed just as cleanly.
Preparing the Deck for Standing Seam
Standing seam panels show every bump underneath them, so deck prep matters more than on most roofs.
Flat and solid
Sheathing is checked for soft spots and uneven joints, and damaged boards are replaced before anything goes down.
Fasteners flush
Protruding nails and old fasteners are pulled or set so they can't puncture the membrane or show through the panel.
Clean and dry
A self-adhered membrane needs a clean, dry surface to bond fully and lay without wrinkles.
Edges in order
Drip edge, eave and valley details are installed in sequence so every lap sheds water downslope.
Installation Details Under Standing Seam
- Heat rating: panels get hot in Florida sun, so the underlayment should be rated for high temperatures under metal.
- Slip sheet: some panel manufacturers require a slip sheet between a self-adhered membrane and the panel so the metal can expand and contract freely. Their instructions take priority.
- Clip fasteners: standing seam clips are screwed through the membrane into the deck, and a self-adhered membrane helps seal around those screws.
- Code and approvals: the installation follows the Florida Building Code and the approval documents for the panel system being installed.
Certifications Behind the Premium Finish
Getting to a Finished Standing Seam Roof
Design consultation
Panel profile, finish and underlayment pairing decided together.
Quote
One number covering both layers of the system.
Deck prep & underlayment
Self-adhered before a single panel is formed.
Standing seam installation
Hidden-fastener panels installed on the sealed deck.
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