Great Stuff Big Gap Filler – Complete Review [2025 Edition]
If you’ve tackled insulation or sealing projects at home, chances are you’ve seen the familiar red-and-yellow can of Great Stuff™ Big Gap Filler. It’s one of the go-to products for homeowners, handymen, and contractors needing a quick, effective, and expandable sealant. But is it worth the hype?
FOAMS
What Is Great Stuff™ Big Gap Filler?
Great Stuff Big Gap Filler is a one-component polyurethane foam that expands to fill large gaps, cracks, and holes up to 3 inches wide. It’s ideal for sealing areas where air, moisture, and pests can enter your home.
Unlike regular insulating foams, this version is designed to expand significantly—making it great for framing, foundation gaps, plumbing holes, and more.
Key Features
Expands to Fill Gaps up to 3”
Closed-cell polyurethane foam
Water-resistant and airtight seal
Dries tack-free in 15 minutes
Fully cures in 8 hours
Can be trimmed, sanded & painted
Technical Specs
PropertyValueApplication MethodStraw Dispenser (included)ExpansionHigh (~2X initial size)Tack-Free Time~15 minutesCure Time~8 hours (24 hrs for full cure)PaintableYesFire-RatedNoShelf Life~12–15 months unopened
Pros
Incredible expansion for large cracks
Very strong adhesion to wood, metal, masonry, and drywall
Prevents air and water infiltration
Helps improve energy efficiency
DIY-friendly straw system
Cons
Can over-expand if not applied carefully
One-time use with the straw canister (can’t reseal)
Requires protective gloves (very sticky)
Not UV resistant — must be painted or covered
Common Use Cases
Gaps between sill plate and foundation
Holes around pipes, ducts, and vents
Openings in attics, basements, rim joists
Fixing cracks in garage walls or exterior siding
Pro Tips for Best Results
Mist the surface before application to speed up curing.
Only fill 50% of the gap — the foam expands!
Wait a full 8 hours before trimming.
Always wear gloves – it sticks aggressively.
Store the can upright if not used immediately.
User Reviews
“This stuff filled the huge gap around my dryer vent perfectly. Just be careful—it really expands.” – ⭐⭐⭐⭐⭐
“Saved me hundreds in energy bills by sealing all attic gaps. Very sticky though.” – ⭐⭐⭐⭐
“Good for big holes, but single-use is a drawback.” – ⭐⭐⭐⭐
Final Thoughts
If you’re sealing large openings or want a durable, expanding foam for weatherproofing, Great Stuff Big Gap Filler is an excellent choice. It’s cost-effective, powerful, and ideal for a range of indoor and outdoor applications (just remember to paint it for UV protection).
🔨 Rating: 4.6/5
📦 Best For: Attics, basements, pipe holes, foundation gaps
💲 Price Range: ~$5–$7 per can
Where to Buy
Amazon
Home Depot
Lowe’s
Walmart