Installing Rolled Insulation

Take for an example installing rolled insulation in the exterior walls of a new room addition. Simply measure the height and width of the walls to determine the amount of square feet of insulation required. An even easier technique is to measure the height of the walls and simply count the number of stud wall bays that you need to insulate. Rolled insulation is available for 16” and 24” stud bays, so by simply multiplying the number of stud bays times the height of the walls and then adding 5%, you can quickly determine the number of linear feet of insulation you need. The linear feet of rolled insulation per roll R-value type is listed on the packaging label, so you can quickly determine how many rolls you need.

Rolled insulation is available in many different R-Values / thicknesses. The most common R-values for walls are R-11 (3.5” thick) and R-19 (6” thick). When installing rolled insulation in an attic, the thickness required is a function of the region of the country you live in, however using R-38 (12” thick) insulation in the attic is a common requirement. Once you have purchased your insulation and are ready to install it, make sure to wear protective clothing that covers your body from head to toe. Rolled fiberglass insulation is irritating to the skin, throat, and eyes so also don’t forget to wear goggles, gloves, and a mask.

Note that when insulating a room, a vapor barrier needs to be installed over the insulation facing the inside of the room. This is automatically achieved with faced insulation. You simply install the faced insulation in the stud bays so that the paper faces inwards towards the room center. If you use unfaced insulation then you will need to apply a sheet of polyethylene plastic over all the walls and rolled insulation. The plastic can be stapled to the wall studs.

Tools required for Installing Rolled Insulation

To install rolled insulation you will need a long straight edge, such as a level or length of 2×4, a utility knife, a staple gun and staples, a putty knife and/or large common screw driver.

Installing Rolled Insulation The best way to install rolled insulation is to first unroll it on the floor, measure and cut it. Use your straight edge and utility knife to cut it. Note that you will need to firmly press down on the insulation to create a clean cut. After cutting a few lengths of insulation simply install them in the wall bays, again with the paper facing inwards towards the room. Staple the paper tabs to the wall stud studs every 12” or so up the length of each wall stud. Once you have installed the insulation in the wall bays, you can then proceed to cut small pieces of insulation and push them into the small crevices around the door and window frames, as well as any narrow bay walls. Use your screw driver and/or putty knife to push the pieces of insulation into the crevices and narrow wall bays.

Note as an alternative to using rolled insulation in the small crevices, you may want to use a can of spray foam insulation. This stuff works great and is much faster and easier to install then bits of rolled insulation.

Make sure when installing the rolled insulation around electrical boxes that you do a neat job and that you apply staples close to the electrical boxes to create a tight seal.

Finally, if you did not use a faced insulation, apply the plastic, or vapor retarder over the insulated walls. It is very important to do this to prevent moisture problems in the walls, so do not skip this step.

With the rolled insulation and vapor barrier installed you are ready to move on to the drywall installation phase of your home improvement project.