Great Stuff Gaps & Cracks vs Window & Door Foam?
By Nate Sawyer, Editor · Updated July 2026
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Great Stuff Gaps & Cracks Insulating Foam Sealant (12 oz)
A high-expansion polyurethane foam that quickly fills large, irregular voids up to 3 inches, ideal for rim joists, penetrations, and pest-blocking. The closed-cell foam adds R-value and blocks air and drafts cheaply. Cautions: it expands aggressively and can bow window or door jambs in tight frames, and cured foam is nearly impossible to remove.
| Type | Polyurethane expanding foam (closed-cell) |
|---|---|
| Expansion | High expansion, fills gaps up to 3 in |
| Cure | Tack-free ~20 min, cut/trim in ~1 hr, full cure ~8 hr |
| Paintable | Yes, after full cure (sand first) |
| Use | Gaps and cracks up to 3 in, indoor/outdoor |
Great Stuff Window & Door Insulating Foam Sealant (12 oz)
A low-expansion polyurethane foam made for the gap between a window or door frame and its rough opening. Its minimal expansion seals and insulates without bowing the jamb or binding the sash, and it stays flexible for seasonal movement. Limits: it is not for gaps over 1 inch, costs a bit more than Gaps & Cracks, and still cures permanent.
| Type | Polyurethane low-expansion foam |
|---|---|
| Expansion | Minimal/low expansion (window & door formula) |
| Cure | Tack-free ~20 min, trim in ~1 hr, full cure ~8 hr |
| Paintable | Yes, after full cure |
| Use | Gaps <1 in around window and door frames |
Our verdict
The single deciding factor is where the gap is. Gaps & Cracks is a high-expansion, closed-cell foam that fills voids up to about 3 inches, making it ideal for rim joists, penetrations, and large openings, but its aggressive expansion can bow a window or door jamb and jam the sash. Window & Door is a low-expansion formula built for exactly that risk: it seals the gap between a frame and its rough opening without distorting the jamb. Rule of thumb: use Window & Door anywhere near an operable window or door, and Gaps & Cracks for everything else. They cost about the same, so keep both on the shelf.
Frequently Asked Questions
- How long does Great Stuff foam take to dry?
- Both formulas behave the same way: tack-free in about 20 minutes, ready to cut or trim in roughly 1 hour, and fully cured in about 8 hours. Wait for full cure before sanding or painting — trimming a foam that is still curing tears the skin and leaves open cells that keep absorbing moisture.
- Is Great Stuff open or closed cell?
- Gaps & Cracks is a closed-cell polyurethane foam, which is why it adds real R-value and blocks air movement rather than just filling space. The Window & Door formula is the same polyurethane chemistry tuned for low expansion; it is chosen for its gentle expansion around frames rather than for insulating value.
- Can I use Gaps & Cracks around a window?
- No, and this is the whole reason the two products exist. Gaps & Cracks expands aggressively enough to bow a window or door jamb and bind the sash, which is a repair far more expensive than the can you saved. Use Window & Door anywhere near an operable window or door.
- What if the gap is wider than an inch?
- Window & Door is rated for gaps under 1 inch, so a wide rough opening needs backer rod first or several thin passes with cure time between them. Gaps & Cracks handles voids up to about 3 inches in one shot, which is why it stays the right pick for rim joists and penetrations.
- Can either foam be painted?
- Yes, both are paintable after full cure. Sand the skin off Gaps & Cracks first so the paint has a flat surface to grab. Note that neither cleans up easily — cured foam is effectively permanent on skin, clothing and trim, so mask before you spray.