Can You Insulate Walls Without Removing Drywall?

Insulating walls of a home can be a key component in achieving high levels of energy efficiency, saving the homeowner a lot of money over time.  While many newer homes have walls (and other areas) that are well insulated, owners of older homes may find that their walls are not insulated properly.  While it seems like an impossible task, homeowners can add insulation behind existing drywall while leaving the drywall intact.  

The solution involves blowing in fiberglass (or cellulose) fiber behind your drywall.  You can turn to an outside insulation contractor to do the work or if you are a DIYer, you can rent insulation blower equipment from a local rental or hardware store.   
Whoever does the work, the process is pretty straightforward and can be done from the interior of each room. Prepare the room by laying down sections of drop cloth to catch drywall cuttings and loose insulation particles. 
You first need to locate studs on a section of wall and mark them all with a heavy carpenter’s pencil, about 6 inches below the ceiling. Using a hole saw, carefully cut 2” diameter circles between your stud markings (6 inches below the ceiling).  The diameter of your holes should be about 3/4” greater than the diameter of the tip of your insulation blower hose.  As you cut these circles in the drywall, be careful to mark and save each piece as you will use them to plug up each hole when you are done.  
You are now ready to begin applying the insulation.  Make sure that you use safety goggles and a breathing mask to protect yourself from floating insulation fibers during application.  Long pants and long-sleeve shirts are also recommended.  
With the help of a friend (who will be operating the insulation blower nearby), begin filling the areas between studs with insulation.  Place the tip of the application hose in the hole and protect the edges of drywall by wrapping a cloth around the hose.  Slowly add insulation until the cavity is full, making sure that the insulation is packed tightly.   When each section is filled, turn off the equipment temporarily and then proceed to the next section. 
After all the holes are filled, carefully place the cut out circles of drywall into each hole and secure with drywall tape.  As you do this, you should feel a bit of resistance from the insulation material inside.  Spackle over each hole and when dry, you are ready to sand and paint.  After the painting is done, the project is finished! 
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