How To Cut Denim Insulation

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Denim insulation is dense and well-insulating. It was developed in the 1980s and has since grown more in popularity. It's also easy to cut and install. But how exactly do you cut denim insulation? We have researched a few different methods to do this. And in this post, we will go over them.

Here are 2 methods you can use to cut denim insulation:

  • Method 1: Use a pair of heavy-duty shears
  • Method 2: Use a utility knife

Denim insulation is made from cotton and blue jeans, both of which are selected from a variety of sources. The best method to cut the insulation will depend on its installation location and the type of denim insulation that you purchase. You can buy insulation in either rolls or batts. Continue reading to learn more.

worker pushing in Recycled Blue Jean Denim Insulation in Wall Frame. How To Cut Denim Insulation

Methods to Cut Denim Insulation

Even though denim insulation isn't toxic to work with like fiberglass insulation, caution should still be taken when cutting it. This means that you should always wear protective equipment including a ventilator mask, thick workman's gloves, and protective goggles.

Two pieces of recycled blue jean denim insulation separated by a wall stud

Method 1. Use a pair of heavy-duty shears

Things you'll need:

  • 2x4 piece of plywood
  • Worktable or 4x4 plywood board
  • Heavy-duty shears
  • Protective equipment

1. Lay the insulation on a table

One of the easiest and quickest ways to cut denim insulation in rolls is to use a pair of heavy-duty shears. Start by unrolling the insulation with the paper side facing down. Place the insulation on a work table. If you don't have an available work table, use a 4×4 piece of plywood.

2. Measure the cut areas

Use a tape measure to determine the areas where the insulation will be cut. Be sure to measure the installation areas beforehand. If you have rolled insulation, only roll out a few feet at a time so that it doesn't fall off of the table and onto the floor.

Mark the cut area on the insulation and then transfer this line to the plywood or work table, so you'll know where to cut. Make sure the line is visible, so it'll need to be past the width of the insulation.

Check out more details on these shears on Amazon.

3. Cut the insulation

Take a 2×4 piece of plywood and place it on top of the insulation where you plan to cut. Next, starting at the side of the insulation closest to you, cut the insulation, moving the blade away from your direction.

You'll need to go over it a few times to cut all the fibers. Continue to hold the plywood piece in place to keep the insulation from moving while you're cutting.

If you need to cut the insulation lengthwise, be sure to make these cuts last. In many cases, you may have extra pieces leftover that you can use for smaller areas anyway.

Method 2. Use a utility knife

Things you'll need:

  • 2x4 piece of plywood
  • Worktable or 4x4 plywood board
  • Utility knife
  • Protective equipment

When cutting denim insulation, you can also use a utility knife with a blade that's at least three to four inches. This way, you won't have to struggle to press the blade through the material as you make each cut.

You should also use a fresh blade when performing this project for the first time. If you don't have a utility knife, a serrated knife (similar to a bread knife) will also work.

1. Place the insulation on the table

Start by placing the roll or batt on your work table or a 4×4 plywood board.

2. Mark the cut areas

Use your pencil to make the measurement marks on the table where you plan to place the cuts. Next, transfer the measurements to the table or plywood board. You'll also want to make sure that the insulation is lined up perfectly with the table or board to make for the most accurate cut.

3. Cut the insulation

Place a 2×4 on top of the insulation on the line where you plan to cut. Next, starting at the top of the insulation, take the blade and drag it down the insulation toward your direction, making sure to firmly press against the fabric.

Drag the blade over the insulation a few times to ensure you've cut through all the fibers. It's best to cut through the paper last, just to make things easier.

When cutting the paper backing, be sure to hold the insulation down firmly with your other hand to keep it from moving--cut this part last. Continue making the cuts until you have all the pieces that you need.

Click to find this utility knife on Amazon.

Want to see how you do it? Check out this video:

What is the Best Thing to Cut Insulation With?

Overall, you'll find that a utility knife or a pair of heavy-duty shears will work best to cut insulation. The thing that can make insulation is the fact that it will often shift during the cutting process. The main thing you'll want to remember is to hold the insulation in place while you're cutting it, especially if you're using a knife or any type of blade.

This is why it's helpful to use a 2×4 piece of plywood when using a blade to cut fiberglass or denim insulation. However, if you have rigid foam panels, you can also use a hand or electric saw to cut them.

Click to find this electric saw on Amazon.

Is it Safe to Cut Insulation?

The process of cutting insulation can be unsafe if the proper precautions aren't taken. You'll want to ensure that any cutting tool that you're using is being handled carefully, especially if it's electric. Also, when cutting fiberglass insulation, take additional precautions to protect yourself.

The reason is that fiberglass insulation contains very thin pieces of glass fiber. These fibers can get into your eyes, skin, and lungs, causing serious health issues. Let's look at how to use safety precautions when cutting fiberglass and other types of insulation.

A small section of recycled blue jean denim insulation sits on a concrete floor near a stud wall frame

Keeping your hands and skin protected

It's always best to ensure that you're working with clean, fresh blades when cutting any type of insulation. Be sure to use handyman gloves and a protective suit to protect your hands and skin from insulation fibers, especially if it's fiberglass (which can cause skin irritation and other issues).

Read more about this protective suit on Amazon

Keeping your lungs safe

You'll also want to use the proper respiratory equipment when working with insulation. This is especially true for fiberglass, cellulose, mineral wool, and denim insulation.

These types of insulation can get a bit messy when you cut them, and inhaling the airborne particles can be especially dangerous. Always use a dust mask or painter's respirator when handling or cutting these materials.

Check out this respirator on Amazon.

Keep your eyes safe

Eye protection is of the utmost importance when working with any type of insulation. Always protect your eyes when using any type of electric cutting tool. Also, the dust created by the cut insulation can cause eye irritation, and it can also lead to other serious issues.

Find these safety goggles on Amazon

Is Denim insulation Fire resistant?

Denim insulation is essentially made from cotton and recycled denim jeans. It's similar to blown-in insulation, as it is considered a Class-A insulation material.

This means that it's treated with a flame retardant chemical, which is likely borate-based. It's also treated with chemicals to help prevent the growth of bacteria and fungi.

blue denim insulation in between wood wall studs

Will Denim Insulation Mold?

If exposed to excessive amounts of moisture and humidity, denim installation can begin to mold. However, it's sprayed with protective material to prevent mold. For example, if you have a busted water heater or a leaky pipe, it can cause the insulation to become drenched with water.

In many cases, the insulation will need to be removed and replaced. But if it is only slightly wet and the room is thoroughly dried out, you may be able to salvage it before mold develops.

However, you all want to monitor the insulation days in a week afterward for any strange smells, or spots that may be a sign that mold has developed on it.

Is Denim Insulation Good for Soundproofing?

Yes. Similar to other types of insulation, denim insulation works wonderfully for soundproofing. The good thing about it is that it's also non-carcinogenic, and eco-friendly. It works perfectly for soundproofing walls, floors, windows, and doors.

It's also fairly easy to install. The biggest downside to using denim over fiberglass insulation is its cost difference. It's typically about 10% more expensive.

Installing Recycled Blue Jean Denim Insulation in Wall Frame, trimming using knife. How To Cut Denim Insulation

Wrapping Things Up

We hope this post has helped explain the best methods and tools for cutting denim insulation. Overall, you'll find that the process to cut this type of insulation is fairly straightforward. However, always use caution when cutting any type of insulation.

This means using protective equipment including a dust mask and skin coverings.

Before you go, be sure to check out our other posts:

How Long Does Insulation Last And When To Replace It

How To Insulate Finished Garage Walls

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