How to Install R19 Insulation

Determine the width required for the R19 insulation by measuring the space between floor joists. R19 insulation comes in in either 15- or 23-inch wide rolls, batts or foam boards. These widths produce the best fit between floor joists measuring 16 and 24 inches respectively.

Measure the length of each rectangular space between the floor joists to determine the length of insulation needed to fill the space. Joists may not always measure half the width of the house, but may be interrupted by pipes or additional header joists built into wide homes or buildings.

Cut pieces of insulation to fit into the spaces using a utility knife for roll or batt insulation and a handsaw for foam board insulation. A utility knife with a plastic hand guard gives your hands protection against irritating particles of insulation and helps take the frustration out of cutting roll or batt insulation. If spaces measure longer than the length of a piece of insulation, cut a smaller piece to fit into the remaining space.

Push pieces of insulation into their appropriate places, according to length. Install insulation so that any available vapor barriers face upward, towards the floor of the home. Pull the extra vapor barrier out to create flaps you can use to staple the insulation into place. Use a construction staple gun and 1/4 inch-long staples to staple the roll or batt insulation to the stringer joists that run across the width of the house; place staples approximately 6 inches apart. Install foam board insulation using furring strips attached to the stringer joists.

Measure, cut and install one piece of insulation at a time to save money and prevent mistakes. Fill gaps between installed pieces using foam spray or smaller cuts of roll, batt or board insulation.