New Build? Here’s When to Use Spray Foam or Batt Insulation

Building a new home or property means making big decisions — and insulation is one that affects comfort, efficiency, and cost for decades. The two most common options for new construction are spray foam and fiberglass batt insulation — but when should you use one over the other?

At EcoMax, we help builders and homeowners across Massachusetts make smart choices for every part of the home. Here’s a breakdown of when to choose spray foam, batt, or a hybrid system that combines both.

Spray Foam: Best for Air Sealing and High Performance

Ideal for:

• Attic roof decks

• Rim joists

• Basements or crawl spaces

• Any area prone to moisture or air leakage

Why choose it:

• High R-value per inch

• Seals cracks, gaps, and framing penetrations

• Creates an air and vapor barrier in one

• Helps meet Massachusetts stretch energy codes

When to avoid:

• Budget is very limited

• Large open areas with few obstacles

Fiberglass Batt: Best for Budget and Speed

Ideal for:

• Interior walls

• Wide-open wall framing

• Ceilings between floors

• Projects where speed and cost are key

Why choose it:

• Affordable and fast to install

• Meets code when installed properly

• Great for sound dampening between rooms

• Compatible with hybrid systems

When to avoid:

• Small cavities or irregular framing

• Spaces with high moisture risk

Hybrid Systems: The Best of Both Worlds

A common EcoMax solution:

• 2” closed-cell spray foam for moisture control + air sealing

• Fiberglass batts on top for cost-effective thermal coverage

Why it works:

• Air sealed + budget friendly

• High performance without breaking the budget

• Meets code and reduces long-term energy costs