Lay Out the Insulation
Begin laying in the insulation, starting at an area farthest from the attic access (Image 1).
When rolling the insulation, cut it to length using a utility knife.
Tip: When you reach the end of a line, pull the insulation back slightly, then place it on a joist so there is a solid surface to cut on. Using a straightedge as a guide, make your cut (Image 2).
After making the first cut, use the remaining portion of the roll and work back in the other direction. When you reach the end of that roll, butt a new roll up to the cut piece and finish the run.
Once the perimater is reached, cut the end of the roll to fit. Using this technique results in the best use of the insulation and reduces wasted material.
Tip: Lay the rows snugly together to prevent undesirable gaps or spacing.