Fiberglass Insulation Installation

Insulation isn’t the funnest thing to do but it is something that has to be done in order to keep the heat in your house.  Heres some tips to make drywall a little easier, stay safe while installing it, and avoid the itch.

Fiberglass insulation when it is cut, ripped, or disturbed in anyway releases its fibers into the air that can cause coughing and sore throat when inhaled and irritate your eyes.   So you should wear safety glasses and a good filtering dust mask or respirato.  It can also cause irritated itchy skin when you touch it so be sure to wear a long sleeve shirt, pants, and gloves.  Baby powder can be put around your neck or anywhere else exposed to prevent the fiberglass from getting into your skin.

Insulation comes in different widths, lengths, and R-Values.  R-Value is the capacity of an insulating material to resist heat flow. The higher the R-value, the greater the insulating power.  Walls are usually R-11 or R-!3 and attics are done with R-30.  Some insulation is sold without a vapor barrier and is called “unfaced”.  If you use unfaced insulation you should put a poly sheeing vaporbarrior over the walls before installing drywall to prevent any moisture that might come through the exterior from causing mold issues.

Safety First the Gear and Tools You’ll Need

  • Safety glasses
  • Gloves
  • good filtering dust mask or respirator
  • Utility knife
  • Straight edge (2′ wide 2×4 or level)
  • Tape measure
  • long piece of scrap drywall or plywood
  • Staple gun

Clear Some Space

You should have a good amount of space cleared out in the room your working on so that you can set up a nice cutting area.  Place the long piece of scrap drywall or really anything to cut on to prevent cutting up your floors.


Measure the stud spacing and height of your walls.  If the walls are the normal 16″ on center then you don’t have to cut the width just the length.  If your walls are 24″ on center and you can buy 24″ O.C. batts of insulation.  In older houses that have balloon framing the walls are 24″ O.C.  If your house was an older house like mine you’ll notice that a lot of the walls don’t have equal stud spacing so you will have to measure and cut the width also.

Cut to Fit

Set the batts of insulation flat on the floor in your cutting area with the fluffy side up and start cutting.  Transfer your measurements and make a small cut with your utility knife to mark your cut about a 1/4″ shorter.  With insulation you don’t have to be exact just close enough.  Use your straight edge to make a nice clean cut on your mark with the scrap piece underneath to protect the floor.  If you need to cut the widths to you can use a long 2×4 as a straight edge.

Fill the Cavities

After they are cut to fit stuff them in the cavities with the paper side out.  If it won’t stay in place you might need to staple the paper to the studs.  It should remain puffy and might stick out an inch or so but this is fine.  What you don’t want to do is try to cram as much insulation you can into a tiny space thinking that it will better insulate the space.  This will do the opposite and make the insulation less effective because it needs to be kind of puffy to have those air pockets.  The air pockets are what keep the heat in.

It’s really as simple as that.  If you have extra cut off scrap pieces you can use them up in any small open cavities where heat could escape.

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