How to Cut Fiberglass Insulation Batts

Jay CorkJay CorkUpdated: Feb. 10, 2023

Cutting batt insulation the easy way

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Time

A full day

Complexity

Beginner

Introduction

Working with fiberglass insulation is never a fun job. But we've got some tips and tricks to help minimize discomfort and the mess associated with cutting it.

Tools Required

  • work gloves
  • straight edge
  • utility knife

Materials Required

  • Fiberglass batt insulation

Project step-by-step (3)

Step 1

Prepare space on the floor

  • To avoid damaging the floor underneath, use a full sheet of plywood or subfloor to cut the insulation on.
  • If your remodel doesn’t yet have a floor, that’s even easier – cut it right on the subfloor.
    • PRO TIP: If you’re cutting many bats at the same length, make some marks on the plywood so you don’t have to measure every single batt.

Tools Needed to Cut InsulationFamily Handyman

Step 2

Use a straight edge

  • Use a straight edge to cut batt insulation.
    • PRO TIP: Using a piece of scrap plywood cut in the shape of an L makes a really good jig to cut straight, square and clean.

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Step 3

Make the cut

  • Using an extendable utility knife, draw the blade toward you along the straight edge.
  • With even downward pressure and a sharp blade, it should cut a perfectly square, clean edge.

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Originally Published: August 02, 2021