MaxFill 1K Spray Foam by DAP – In-Depth Review [2025 Update]

If you're a DIY enthusiast, contractor, or homeowner looking for a high-performance gap filler, you've probably come across DAP MaxFill 1K Spray Foam. In this review, we break down what makes MaxFill a reliable choice for insulation, sealing, and energy efficiency.

What Is DAP MaxFill?

DAP MaxFill is a one-component polyurethane spray foam designed to expand and fill large gaps and cracks. It's dispensed from a can, reacts with moisture in the air, and cures into a rigid foam that seals out air, moisture, and pests.

Key Features

• High Expansion: Expands up to 3X to fill large voids.

• R-Value: Adds insulation value to walls, ceilings, and floors.

• Moisture-Resistant: Helps block air and water infiltration.

• Easy Application: Straw or gun-dispensed for targeted application.

• Paintable: Once cured, it can be trimmed and painted over.

• Compatible Substrates: Wood, drywall, masonry, metal, concrete, and more.

Technical Specs

PropertyValueType1K Polyurethane FoamExpansionHighCure Time8–24 hours (full cure)Tack-Free Time~10–15 minutesShelf Life~12–15 months (unopened)ColorOff-white/yellowishDispense Temp Range60°F – 100°FApplication MethodStraw or gun

Pros

• Easy to use for beginners

• Quick sealing of large cracks

• Affordable and widely available

• Reduces energy loss

• Good adhesion to multiple surfaces

• Low expansion risk compared to some 2K foams

Cons

• Can over-expand in tight spaces if not careful

• Can is not reusable after use unless gun-dispensed

• Strong odor during application (ventilation recommended)

• Not suitable for fire-rated assemblies or constant UV exposure

🏠Best Use Cases

• Sealing gaps around pipes or wall penetrations

• Filling rim joists and sill plates

• Around window and door frames (if using low-expansion variant)

• Fixing drafty attics or crawlspaces

Tips for Application

1. Shake well before use (20–30 seconds).

2. Apply with can upside down.

3. Don’t overfill – the foam expands as it cures.

4. Mist surface lightly with water for faster curing.

5. Trim excess foam after curing with a knife or saw.

Customer Feedback

“MaxFill was perfect for closing the air gaps in my attic. It expanded nicely and really reduced my energy bill.” – ⭐⭐⭐⭐⭐

“A little tricky at first, but once you get the hang of it, it seals great.” – ⭐⭐⭐⭐

“Good value for the price. I just wish the straw attachment was reusable.” – ⭐⭐⭐⭐

Where to Buy

You can find DAP MaxFill at:

• Home Depot

• Lowe’s

• Amazon

• DAP’s official website

Final Verdict

If you're looking for a cost-effective, easy-to-apply solution to insulate and seal your home, DAP MaxFill 1K Spray Foam delivers solid performance. While it's not a professional-grade 2K foam, it’s perfect for most home and light commercial applications.

✅ Rating: 4.5/5
📦 Best For: DIY insulation, gap filling, energy efficiency