What benefit does estimating an additional square for hips provide when calculating the number of bundles of shingles needed?

Estimating an additional square for hips when calculating the number of bundles of shingles needed primarily accounts for the complexity of roofing surfaces. Hips are the sloped edges that form where two roof sections meet, and they often require additional materials to ensure proper coverage and waterproofing.

By including an extra square for these areas, you are effectively allowing for the unique angles and shapes that can complicate the shingle layout, resulting in a more accurate material requirement estimate. Complex areas may also involve more waste due to cutting and fitting shingles to meet the specific angles and curves of the hip, which the extra square helps to mitigate.

Thus, this practice ensures that there is enough material to cover not only the flat sections of the roof but also these intricate parts, preventing shortages during installation and ensuring a more reliable and watertight roof.