DEI 50520 Floor and Tunnel Shield II Non-Adhesive 42in x 48in Heat Barrier 1750F Universal

The 50520 Floor and Tunnel Shield II (Non-Adhesive) is a universal thermal and acoustic barrier sheet measuring 42 inches x 48 inches, engineered to block radiant heat up to 1,750 degrees F while reducing road noise by up to 50 percent. Whether you are building a track car, restomod, off-roader, or daily driver, this barrier delivers professional-grade thermal isolation for transmission tunnels, floor pans, firewalls, and engine compartments in a single cut-to-fit sheet. Made in the USA from a three-layer composite construction, this 14.0 sq ft panel handles real heat without an adhesive backing, so you fasten it exactly where you need it with rivets or screws.

How the Three-Layer Construction Works

The DEI Floor and Tunnel Shield II earns its 1,750-degree-F rating through a purpose-built three-layer stack, not a single material compromise.

• Layer 1 (heat side): Embossed 10 mil aluminum face. The dimpled surface faces the heat source. The embossing pattern increases surface area and reflects radiant energy away before it can travel deeper into the barrier.
• Layer 2 (core): 1/8 in. composite glass-fiber core. This structural middle layer provides the thermal mass and the acoustic damping that cuts road noise by up to 50 percent. Glass-fiber composite does not compress over time the way foam-based deadeners do.
• Layer 3 (back): Finely woven glass-fiber backing. The non-adhesive backing sits against your vehicle surface. Because it carries no adhesive, you are not fighting a dried-out peel-and-stick sheet during installation. Fasten it with rivets or screws and it stays exactly where you put it for the life of the build.

Total thickness is 3/16 in., keeping the profile low inside confined tunnel and floorpan spaces where headroom is limited.

Applications

This is a universal fit sheet. It ships as a flat 42 in. x 48 in. panel that you trim with aviation snips or heavy scissors to match your vehicle's exact contour. There is no vehicle-specific fitment list. If you have a heat problem in any of the areas below, this sheet addresses it.

• Transmission tunnels and tunnel plates: Primary application. Block heat radiated from exhaust pipes running beneath the tunnel and reduce drivetrain noise transmitted through the floor.
• Floor pans and floorboards: Protect passengers and electronics from heat soak and high-frequency road noise from pavement contact.
• Firewalls: Separate engine bay temperatures from the cabin without adding significant weight or bulk.
• Fuel cell surrounds: Provide a thermal buffer between exhaust components and fuel storage areas.
• Under-hood areas: Line hood undersides or inner fender areas to manage heat and noise from the engine bay.
• Under-vehicle and underbody panels: Exterior underbody mounting to shield floor pans from road and exhaust heat below.
• Engine compartments: Firewall-adjacent surfaces, strut towers, and inner fender liners.

Important: Do not apply this shield directly to exhaust pipes, catalytic converters, or any surface where the material would make sustained contact with a component exceeding the rated temperature on the back side. The aluminum face must always face the heat source.

What's Included

• 1 sheet, DEI Floor and Tunnel Shield II (Non-Adhesive), 42 in. x 48 in.
• Installation instructions

Not included: Fasteners (rivets, screws, or bolts) must be purchased separately. This is the non-adhesive version and no adhesive is included. If you prefer an adhesive-backed version of the same size, see the DEI 50503 listed in the comparison table below.

Installation Overview

Because this shield is non-adhesive, the installation process is straightforward: measure, mark, cut, and fasten. No heat gun or liner removal is required to activate an adhesive.

• Tools needed: Aviation snips or heavy-duty scissors, marker or chalk, measuring tape, drill, rivet gun or screwdriver.
• Step 1: Make a paper or cardboard template of the area you are covering (tunnel plate, floor section, firewall panel).
• Step 2: Trace the template onto the shield sheet and cut to shape. The material cuts cleanly with aviation snips. Wear gloves when handling cut edges.
• Step 3: Position the panel with the embossed aluminum face pointing toward the heat source (exhaust side, engine side). The woven glass-fiber backing faces the vehicle surface.
• Step 4: Fasten with rivets or screws through the panel and into the vehicle structure. Space fasteners every 4 to 6 inches around the perimeter for a secure hold. Pop rivets in 1/8 in. diameter work well for sheet metal applications.
• Step 5: Trim any final edges as needed. No curing time required.
• Maintain adequate clearance from moving drivetrain components and sharp edges that could abrade the material over time.
• For large areas requiring multiple pieces, overlap panels by at least 1 inch to eliminate thermal gaps at seams.

Full Specifications

Compare: Floor and Tunnel Shield II Line

DEI's Floor and Tunnel Shield II is available in multiple sizes and with or without adhesive backing. All versions share the same three-layer aluminum-face and glass-fiber construction and the same 1,750-degree-F temperature rating. Choose based on the size of your application and whether you prefer a riveted or adhesive-bonded installation.

If your project calls for the adhesive version at the same 42 in. x 48 in. size, the DEI 50503 covers the same area and bonds directly to the vehicle surface without fasteners. If you need coverage for a smaller zone, the DEI 50506 at 24 in. x 42 in. (7.0 sq ft) reduces material waste on compact sections like a single transmission tunnel plate. The DEI 50560 provides the same non-adhesive, rivet-mount installation in a black finish, which suits builds where appearance of the shield face matters.

Warranty and Legal

The DEI Floor and Tunnel Shield II carries a 90-day limited manufacturer warranty covering defects in materials and workmanship from the date of purchase. This warranty does not cover damage from improper installation, misuse, or application outside the product's stated temperature range.

California residents: This product contains chemicals known to the State of California to cause cancer and reproductive harm. See www.p65warnings.ca.gov.

About Design Engineering, Inc. (DEI)

Design Engineering, Inc. has been developing thermal management and acoustic products for motorsport and street performance since 1995, operating out of Avon Lake, Ohio. DEI's product line spans heat wrap, exhaust insulation, under-hood barriers, fire protection sleeves, and acoustic deadening material used on everything from NASCAR pit equipment to custom street builds. The Floor and Tunnel Shield II line is manufactured in the USA and reflects DEI's commitment to materials that perform under real racing and high-performance driving conditions, not just laboratory averages.

Frequently Asked Questions

What vehicles does this heat shield fit?
This shield is a universal product. It is not engineered for a specific year, make, or model. The 42 in. x 48 in. sheet is designed to be cut and trimmed to fit any vehicle, from a 1969 muscle car resto-mod to a current-generation truck or off-road build. If your target surface is 14.0 sq ft or smaller, a single sheet covers it. Larger areas require multiple sheets with overlapping seams.

Does the 50520 have adhesive backing?
No. This listing is specifically the non-adhesive version of the Floor and Tunnel Shield II. The back layer is a finely woven glass-fiber material with no peel-and-stick surface. You fasten it using rivets or screws, which you purchase separately. If you want an adhesive-backed version in the same 42 in. x 48 in. size, order the DEI 50503 instead.

How hot can the Floor and Tunnel Shield II handle?
DEI rates the Floor and Tunnel Shield II for up to 1,750 degrees F (954 degrees C) of direct heat resistance. This covers the surface temperatures generated by most exhaust systems running beneath a tunnel or floorboard. Always orient the embossed aluminum face toward the heat source. Do not mount the shield in direct contact with exhaust pipes or catalytic converters, which can exceed localized surface temperatures well beyond the ambient radiant heat the shield is rated for.

What fasteners do I need to install this shield?
DEI recommends rivets or screws for mounting. Standard 1/8 in. aluminum pop rivets work well for most sheet metal floor pan and tunnel applications. For composite or fiberglass surfaces, use stainless screws with a large-diameter backing washer to distribute clamping load. Space fasteners 4 to 6 inches apart around the panel perimeter. Fasteners are not included and must be purchased separately.

How do I cut this heat barrier to size?
The material cuts cleanly with standard aviation snips or heavy-duty scissors. For best results, make a cardboard template first, trace it onto the shield sheet with a marker, and cut along the line. The glass-fiber layers can release fine fibers at cut edges, so wear gloves and safety glasses when trimming. Edges do not require sealing after cutting.

Can this shield be mounted on the outside of my vehicle, under the floor pan?
Yes. This shield is rated for underbody exterior mounting. Fasten it securely to prevent wind lift and ensure no edges can catch airflow at highway speeds. For exposed underbody installations, rivet spacing should be tighter (every 3 to 4 inches) and a corrosion-resistant fastener (stainless or zinc-coated) is recommended due to road moisture exposure.

How does the Floor and Tunnel Shield II reduce road noise?
Sound deadening comes from the 1/8 in. composite glass-fiber core layer. Glass-fiber composite converts acoustic energy (vibration traveling through the floor pan metal) into low-level heat through internal friction in the fibers. DEI rates this at up to 50 percent reduction in road noise transmitted through the treated surface. Results vary depending on how well the panel is fastened (gaps reduce contact and acoustic transfer) and the baseline noise level of the vehicle.

What is the difference between the silver 50520 and the black DEI 50560?
Both are the same non-adhesive, 42 in. x 48 in. Floor and Tunnel Shield II with the same three-layer construction and 1,750-degree-F temperature rating. The difference is the face color: this silver version has an embossed aluminum face and the DEI 50560 has a black face finish. The black version (DEI 50560) is priced higher versus lower cost for this silver version. Choose black if the shield face will be visible in your finished interior or engine bay and you prefer a stealth appearance over bare aluminum.

Will this heat shield void my factory warranty?
A heat shield applied to the floor pan, transmission tunnel, or firewall is an accessory installation and does not modify powertrain, emissions, or safety-critical systems. It does not affect your factory warranty coverage. If you have specific warranty concerns for your vehicle, confirm directly with your dealer before installation.

Does the Floor and Tunnel Shield II require any special surface preparation?
No chemical prep is needed because this shield has no adhesive to bond. Clean the mounting surface of loose rust, oil, or debris to ensure the panel lays flat and fasteners achieve solid engagement. Wipe down with a degreaser if the surface has oil film from undercoating or engine bay spillage. A flat, clean contact surface improves acoustic performance by eliminating gaps between the shield and the floor.