Spongy fiberglass or glass wool are often used in batt insulation. The R-value, or thermal resistance, of batting is compromised if it is folded or tucked too tightly between apertures, hence it is critical to trim batting to fit well. Before you learn how to cut batt insulation you need to know some of the fiberglass insulation cutting tools.
Here we will use a utility knife with a four-inch blade, some extra blades in case one gets dull, measuring tape and a straight 2-by-4 to be the guide.
When you’re done cutting, tidy up using some simple techniques.
How to Cut Fiberglass Batt Insulation
Always protect yourself first
Fiberglass insulation contains microscopic shards of glass that irritate the skin, eyes, and respiratory system. Put on some basic protection gear before opening the package. Long-sleeved shirts with a loose fit will help protect your arms and torso.
Cover your legs with long pants. To prevent fiberglass off your hands and limit the risk of a cut, wear work gloves. Eye protection is provided with safety glasses with sides, and a dust mask lowers the risk of breathing fiberglass particles floating in the air. It’s also a good idea to wear sturdy shoes, long socks, and a hat.
Find a comfortable work surface
To cut the insulation batts, choose a smooth surface. Sliding your knife blade across an old sheet of plywood on the floor is a smart idea. The hardwood surface also serves as a place to scribble down measurements and protects your floor from dents and damage. It will not, however, dull your blade like concrete will.
Before you start cutting it, make sure your batt is easy to measure. Fiberglass insulation is supplied in a large roll, which must be rolled out with the paper side down. However, it’s ideal to start small and gradually expand.
Make a lasting mark on the insulation with a permanent marker. To transfer your measurements to the insulation, use a tape measure. Make small markings along the sides of the insulation to indicate where you plan to cut it. You don’t have to trace each incision in its entirety.You might also use a small piece of masking tape to label the insulation.
Use a straight 2-by-4 that is at least one foot longer than the insulation for your guide. Because you’ll likely kneel on the board and grab it with your free hand for stability while cutting, the thickness of the lumber provides additional protection from the knife.
How to cut insulation batt for wall
Insulation batts are often cut to fit between standard 12 to 24-inch wall studs. You will, however, frequently encounter an unusual gap to fill, either at the top or bottom of a wall or even under a window. Add 1 inch to the length and width of the piece after measuring the uneven aperture.
The extra size will ensure a snug, but not overly so, fit. If your batts have a paper, foil, or vinyl backing on one side, make your cuts with the backing-side down. Fluff or pull the insulation forward after placing it into position to fill the entire cavity, whether you’re using faced or unfaced batting.
Last but not least, tidying things up
For cleaning up after any home renovation project, a wet/dry shop vacuum is a must-have item. Small fragments of batt insulation left behind after cutting can float in the air and drift throughout the room, especially when stirred up by the vacuum’s exhaust. Use a spray bottle to spray a fine mist of water into the air before turning on the vacuum to weigh down the fibers.
After knowing how to cut batt insulation, you must understand that cutting fiberglass insulation is a nasty and possibly dangerous operation for many tradesmen and homeowners. A final tip, if you cut fiberglass insulation and come into contact with it, wash it off with warm water.
If your skin becomes inflamed, wash it with soap. To make cutting fiberglass insulation safer for everyone, follow these procedures.