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The Best FIT for Two-Layer Underlayment Installs

Two-layer roof installs have always come with built-in waste. Standard underlayment applied at the eave edge and the roof ridge introduces unintentional, unneeded triple layering at the overlaps—and that material waste hits your bottom line.

But not anymore: STINGER EXO25 FIT™ solves the issue with a purpose-built, half-roll that fits exactly where it's needed, delivering code-compliant coverage without the excess. By eliminating triple-stacked underlayment, EXO25 FIT™ keeps your coverage efficient and costs in check from the first underlayment course to the last.

The Right Fit for Two-Layer Installs

In high-wind zones, or any job where code requires two-layer underlayment, such as Florida Building Code, Fortified Home Requirements, and low slope roof decks must be covered using a 50% plus 2-inch overlap. This creates a staggered double barrier that offers better protection against wind-driven rain, but it also introduces two key points of underlayment waste: the bottom edge and the ridge.

At the bottom edge, you typically start with two full-width rolls stacked one on top of the other. When the next course is overlapped, the result is a triple layer across half the span. That extra material provides no added value but still costs you.

At the ridge, the same issue plays out in reverse: to finish the row, another full-width roll is used, again creating unnecessary overlap and wasted underlayment.

STINGER EXO25 FIT™ solves both problems with a single, well-sized solution. Acting as a half-layer, it replaces the first full-width roll at the start of the install and caps off the ridge cleanly at the end, eliminating triple layers without compromising coverage.

On average, using EXO25 FIT™ saves roughly a full roll of underlayment for every 25-30 squares installed. That's efficiency built into every two-layer install, right where it counts.

Designed for the Jobsite

From the first row at the eave to the last row at the ridge, STINGER EXO25 FIT is optimized for work site efficiency with pros like you in mind. At just 10 pounds per roll, it's lightweight and easy to handle. The preprinted fastening pattern speeds up installation and keeps your fastener spacing consistent.

Underfoot, STINGER's proprietary slip-resistant coating on the backside, combined with a spunbond non-woven walking surface, provides superior traction and walkability for a safer, more easily navigated jobsite.

And if you need more time before installing the roofing, EXO25 FIT™ is UV-resistant for up to six months, giving you flexibility to work around schedules and weather delays.

Compatible, Reliable, and Code-Ready

You can use STINGER EXO25 FIT™ under asphalt shingles or metal roofing, and it's tested to meet the toughest standards. It's also covered by the same warranty as the full EXO Underlayment line by STINGER, along with any other brand's warranty you're working with.

Combine EXO25 FIT™ with our collated cap fasteners and you'll create a moisture barrier that's tested and approved in winds up to 180 mph. STINGER cap fasteners deliver reliable hold with a plastic cap that seals tight, reducing moisture penetration and keeping your EXO underlayments in place, even in extreme conditions​.

Pro Takeaways

STINGER EXO25 FIT™ is a small, innovative change in how you tackle double layering that can have a big impact on your material usage and project costs, while supporting you and your crew at the work site EXO25 FIT™:

In roofing, there's plenty you can't control—but your underlayment coverage shouldn't be one of them. EXO25 FIT™ gives you a smarter way to meet code without wasting rolls, over-layering transitions, or hauling more material than your two-layered roofs require. It's the right fit for the start, the finish, and your bottom line.