Home Addition Plus

Helping Homeowners Every Day

    Home How-To Store Ebooks    Bid Sheets HouseSight About Us Contact





Home Addition Bid Sheet



How to Cut Fiberglass Insulation Rolls and Batts


Cutting Fiberglass Insulation Requires a Sharp Utility Knife, a Straight Edge, and a Smooth Cutting Surface


By Mark J. Donovan




Fiberglass insulation rolls and batting are used to insulate walls, floors, and attic spaces. Fiberglass insulation is the most common type of house insulation. Installing fiberglass insulation is something most homeowners can tackle, however it is important to use the right tools. Cutting fiberglass insulation, for example, requires a utility knife with plenty of extra sharp blades. You also need a straight edge, such as a carpenters square or a 2 foot length of 2x4, to help compress the fiberglass insulation when cutting it.

Cutting Fiberglass Insulation for Standard Stud Bay Widths

To cut fiberglass insulation first measure the length of the wall stud bay.


Then roll out the insulation onto a smooth cutting surface area such as a subfloor. Using a measuring tape, and the utility knife and straight edge, cut a length of fiberglass insulation approximately one inch longer than your measurement.

When cutting fiberglass insulation, place the straight edge across the length of fiberglass insulation roll or batt where you’ve measured, and put your knee on it to compress it firmly against the subfloor.


Then use your utility knife to cut through the insulation. Note that you may need to make a few passes with the utility knife to cut through the insulation cleanly.


If you are installing faced fiberglass insulation, cut it so that the face side is down against the subfloor. This way you’ll be less likely to tear the facing paper as you cut it.


Once you have cut the fiberglass insulation to length simply push it into place in the stud bay.


Make sure to push it firmly up against the back wall of the stud bay and then pull the outer edges of the insulation to the edges of the wall studs. If you are installing faced insulation, the facing should face the interior of the room. Staple the faced insulation tabs to the wall studs on the inside edges.


Cutting Fiberglass Insulation for Narrow Bay Widths

To cut unfaced fiberglass insulation for narrow stud bays it is often better to cut it in place, after it has already been installed in the narrow stud bays.

It's important to cut fiberglass insulation neatly as seen here to prevent gaps or voids in the stud bays.

Photo By Mark Donovan

If cutting faced fiberglass insulation for narrow stud bays, it is best to cut it as you would normal stud width bays. However, you’ll need to cut it to both the proper height and width. When cutting faced fiberglass insulation to the required width, simply press down on the insulation with your straight edge, make a cut, and then move the straight edge forward and cut again. Continue this process for the length of the insulation piece. 


Get free insulation contractor price quotes.

Related House Insulation Information


Fiberglass Insulation from Amazon.com




Free Room Addition Price Quotes with No Obligation!

Fill out our 3-5 minute quick and easy form, and receive a free price quote on a room addition from one of our prescreened and licensed home addition contractors. This process is free and there is no obligation to continue once you receive your room addition estimate.








- How to Cut Fiberglass Insulation Rolls and Batts -

[Back to Home Insulation]



Follow HomeAdditionPlus on Twitter

to HomeAdditionPlusVideos / Subscribe to HomeAdditionPlus.com feed

Advertise / Favorite Links / SiteMap / ToS / Privacy Policy / Disclosure Policy

Copyright 2005-2016 by DIY HomeAddition Plus.com - A Do it Yourself Home Improvement Site



web metrics