Standard Attic Insulation Width

This type of insulation is ideal for attics with standard spaced beams and joists.

Standard attic insulation width.

Standard joist spacing for the installation of attic flooring materials is 16 inches on center oc meaning the distance from the center of one joist to the center of the next joist is 16 inches. If your current insulation is only five inches deep you will need to add seven inches of insulation to achieve the 12 inch r 38 rating. Insulating attics is rather straightforward but keep in mind these two important factors. If you think you re among the 90 of us homes that are under insulated 1 performing a simple insulation inspection will help you determine your insulation needs.

First be careful when insulating around recessed light fixtures. Measure the length and width of the area you need to insulate. The higher the r value the better the thermal performance of the insulation. Find your zone on the map and then use the chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces.

Minimum opening size the 2012 international residential code requires an attic access opening for attics with an area greater than 30 square feet and a vertical height in excess of 30 inches. Proper attic insulation is the best way to prevent heat loss in the winter and retain cool air in the summer. R value is a measure of insulation s ability to resist heat traveling through it. Striking a perfect balance between too little insulation and too much insulation will keep you and your family warm throughout the winter.

Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. Batten insulation is available to fit all three spacings but not all lumberyards stock all three sizes. Measure the area needing insulation. If it s a standard fixture which typically has a cylindrical metal can projecting up into the attic do not allow any insulation to contact the fixture.

Insulation level are specified by r value. The table below shows what levels of insulation are cost effective for different climates and locations in the home. Multiply the length times the width to determine the square footage of the space.