INSULATION MARKETPLACE SmartSHIELD -1.5mm 48" x100ft Reflective Insulation roll 400 Sq. Ft., Foam Core Radiant Barrier, Thermal Insulation Shield - Commercial Grade - Foil / Foil

A thin, shiny fix that actually moves the comfort needle

I put the SmartSHIELD 1.5mm to work in two places that typically give me temperature headaches: a detached garage with a low, uninsulated ceiling, and the joist bays of a room over a vented crawl space. I wasn’t expecting miracles from a 1.5 mm foam core with foil on both sides, but used correctly, this roll did more than I anticipated—especially for radiant heat control and moisture management—without the mess or itch of traditional insulation.

What it is (and isn’t)

SmartSHIELD 1.5mm is a 48" x 100' roll (400 sq ft) of closed-cell polyethylene foam laminated with reflective aluminum on both faces. It’s lightweight, cuts easily, and behaves as both a radiant barrier and a vapor barrier. That last part matters: it is essentially impermeable, so placement relative to your climate and assembly is important.

Think of it as a radiant and air/vapor control layer with a small bump of conductive insulation from the foam. It’s not a replacement for bulk insulation when you need high R-values. Instead, it complements batts or rigid foam by reflecting radiant energy and blocking air and moisture movement. The claimed R-value of 10.67 is best understood in the context of specific assemblies with air gaps; the material itself is thin, so the big gains come from managing radiation and air, not stacking inches of foam.

Installation: quick, clean, and forgiving

This is one of the easiest insulation products I’ve installed. I cut it with heavy scissors and a utility knife on a sacrificial plywood sheet. It doesn’t shed fibers or dust, and there was no odor out of the bag. The 48-inch width is handy for covering bays or creating wide bands without lots of seams.

• Garage ceiling: I fastened it to the bottom of roof rafters, then later to the underside of ceiling joists. A standard staple gun and 1/2" staples worked, though plastic cap staples hold even better. Wherever possible, I preserved at least a 3/4" air gap in front of one foil face (that gap is what makes a radiant barrier effective). I sealed seams and penetrations with foil tape to improve air tightness and continuity.
• Crawl space: I stapled it to the bottom of the subfloor joists, foil side down, again maintaining an air space. Seams were taped, and perimeter edges were sealed to the rim joist for a continuous vapor retarder above the crawl space air.

The material feels tougher than bubble-foil products I’ve used. It doesn’t kink as easily, resists tearing at staples, and lies flatter against framing. Because both sides are reflective, orientation isn’t fussy—what matters is preserving the air space on at least one side.

Performance: measurable comfort gains

In the garage, the effect during summer afternoons was noticeable. Before installation, the interior ceiling surface was hot to the touch and the space lagged far behind outdoor cooling in the evening. After installing SmartSHIELD with an air gap and taping seams, surface temperatures at the ceiling dropped substantially in direct sun, and the garage interior ran several degrees cooler during peak heat. It didn’t turn the garage into a conditioned room, but it curbed that radiative blast from the roof deck and slowed the heat soak.

In shoulder seasons and mild winter days, it helped the opposite problem—heat loss by radiation—by reflecting warmth back into the space. With an electric heater running, I observed quicker warm-up and less stratification near the ceiling.

The crawl-space application made the floor above feel less “cold-to-the-touch” on bare feet. The change isn’t dramatic like adding thick batts, but it’s perceptible. More importantly, sealing the seams and edges reduced musty air infiltration from the crawl and cut down on seasonal condensation on ductwork nearby. The foil surface also brightens cramped spaces, making inspection and future work easier.

A few side observations:
- Noise: Slight dampening of “drum” resonance on thin metal surfaces. Don’t expect acoustic insulation.
- Moisture: Acts like a true vapor barrier. In areas prone to condensation (e.g., under metal roofing or on steel doors), it’s helpful if positioned correctly.
- Durability: After stapling, pulling, and re-stapling during layout, the foam core didn’t crumble, and the foil face didn’t delaminate.

Where it fits best

• Radiant control in hot roofs and metal buildings: Under roof decks, in sheds, garages, and pole barns where the biggest problem is radiant heat gain. Preserving an air gap is key.
• Vapor barrier plus radiant layer in crawl spaces and basements: When you need a clean, continuous vapor retarder that also reflects heat back toward the conditioned side.
• Retrofit applications: Over existing batts to improve air control and add a radiant component without adding much thickness or weight.
• Odd jobs: Lining metal doors, behind radiant heaters as a reflector, or as a temporary thermal curtain. It cuts cleanly enough to be handy in small projects.

Limitations and caveats

• Not a substitute for bulk insulation: If you’re targeting high R-values in cold climates, you still need batts, blown-in, or rigid foam. Pairing SmartSHIELD with bulk insulation can be excellent, but the foil layer alone won’t carry the load in deep winter.
• R-value claims depend on installation: The best performance requires an adjacent air space; pressing it tight against another surface reduces the radiant barrier effect.
• Vapor barrier considerations: In cold climates, placing a vapor-impermeable layer on the wrong side of an assembly can trap moisture. Know your climate and assembly, and follow local codes and building-science best practices.
• Fire and code: Check flame-spread ratings and ignition barrier requirements where you plan to leave it exposed. Some jurisdictions require a thermal barrier (like drywall) over reflective insulation.
• Dust: In horizontal or upward-facing applications where dust can settle on the foil, reflectivity will diminish over time. Vertical or enclosed cavities are less affected.

Practical tips from the install

• Use foil tape, not cloth duct tape, for seams and penetrations; it adheres to the foil facing and won’t sag.
• Maintain a consistent air gap (3/4" to 1-1/2") on at least one face for radiant performance. Furring strips help in tricky areas.
• Don’t over-staple; a staple every 6–8 inches with occasional cap fasteners holds well without tearing.
• Pre-cut strips on a clean surface and label lengths; the material is forgiving, but accuracy saves time on a ladder.
• Plan transitions: At edges, turn the material onto framing and tape for a continuous air/vapor layer. Pay attention around can lights, vents, and electrical boxes.
• Keep it clean: In open areas, consider a light, breathable covering or orientation that resists dust settling if long-term reflectivity matters.

The bottom line

SmartSHIELD 1.5mm earns its keep as a radiant and vapor barrier that’s easy to handle, clean to install, and durable enough for real jobsite use. It won’t replace thick insulation, but in the places where radiant transfer and air/moisture movement dominate—garages, metal structures, crawl spaces—it makes a tangible difference for not much effort. The double-sided foil and foam core are a step up in feel and performance from the crinkly bubble wraps I’ve used, and the 48" x 100' roll is a practical size for tackling whole rooms or multiple smaller projects.

Recommendation: I recommend SmartSHIELD 1.5mm for anyone who understands what a radiant/vapor barrier can (and cannot) do and needs a fast, clean install. It’s an effective layer to add to hot roofs, metal buildings, and crawl spaces, and a smart companion to traditional insulation when you want better comfort without a major rebuild. If your primary goal is high R-value in a cold-climate wall or attic, combine this with bulk insulation—or choose thicker materials—because no thin foil-faced product alone will meet those targets. Used appropriately, though, this roll punches above its thickness and delivers solid value.