If you're staring at a project and wondering whether you need a roll of reflective insulation or a can of expanding foam, you're actually choosing between two different jobs. The SmartSHIELD 10mm R22 Reflective Insulation Roll covers big surfaces - think attic, ceiling, wall, roof - with a radiant barrier that reflects heat. The Dow Great Stuff Gaps & Cracks Expanding Foam Sealant handles the small stuff: filling cracks and gaps up to an inch wide to stop drafts and air leaks. Both have a place in an insulation drywall ceiling system, but which one should you buy today?
Quick verdict: Go with the SmartSHIELD roll if you're insulating a large area and want a radiant barrier plus vapor control. Grab the Dow Great Stuff foam if you're air-sealing small gaps around pipes, existing insulation, or wood.
| Product | Price | R-Value | Coverage | Best For |
|---|---|---|---|---|
| SmartSHIELD 10mm R22 Reflective Insulation Roll | $549.95 | R22 | 500 sq ft | Large surfaces: attic, ceiling, wall |
| 4 Cans Dow Great Stuff Gaps & Cracks Foam Sealant 12oz | $23.41 | R2 | 5 sq ft | Sealing gaps & cracks up to 1 inch |
Where each product wins
The SmartSHIELD roll wins for whole-room and whole-building insulation jobs. It comes as a 60" x 100' roll, and is built with foam and foil to act as a radiant barrier. It reflects up to 95% of radiant energy and includes a vapor barrier that resists moisture and condensation. That's a serious addition to a ceiling or wall assembly.
The Dow Great Stuff foam wins for sealing and air retention. It's a polyurethane foam that expands to fill cracks and voids, bonds to wood, concrete, PVC/CPVC pipes, and existing insulation, and becomes tack free in 15 minutes and trims in 30 to 60 minutes. It also stays paintable and stainable, so you can finish over it.
SmartSHIELD 10mm R22 Reflective Insulation Roll
If your project covers a large square footage, this roll is the clear choice. It's rated R22 and comes as a 60" x 100' roll, built to handle big surfaces like attics, basements, ceilings, exterior walls, and floors. The foam core and foil facing reflect heat and create a moisture barrier, which helps avoid the mold and dampness that can come with condensation. The limitation: it's not intended for narrow cracks - you'd still need a sealant for gaps. So think of it as the big-surface solution in your insulation drywall ceiling system.
4 Cans Dow Great Stuff Gaps & Cracks Expanding Foam Sealant 12oz
This is the problem-solving sealant for the spots a roll can't reach. The four pack costs $23.41, making it an easy add-on when you're already working. The straw applicator lets you inject foam directly into small gaps up to an inch. It expands to fill the void, hardens into a durable, weather-tight seal, and sticks to wood, concrete, existing insulation, and PVC/CPVC. It's tack free in 15 minutes and trims in 30 to 60 minutes, and you can paint or stain it afterward. The limitation is coverage: only 5 square feet is listed for the pack, so don't expect to cover a wall. This is a gap-and-crack specialist, not a blanket insulator.
Final choice by use case
For a large insulation project - an attic, ceiling, or wall - the SmartSHIELD roll gives you the surface coverage and R-value you need. For sealing the edges, joints, and pipe penetrations that leak air, the Dow Great Stuff foam is faster, cheaper, and simpler to apply. Many people end up using both in the same insulation drywall ceiling system: the roll for the big areas, the foam for the cracks.
