What should be done to a subfloor before installing new flooring?

Before installing new flooring, it is essential to ensure that the subfloor is clean, dry, and level. A clean subfloor is crucial because dirt, dust, and debris can interfere with the adhesion of the flooring material, leading to potential issues such as bubbling, lifting, or uneven wear.

Additionally, a dry subfloor is important, as moisture can compromise the integrity of the flooring and may cause mold or mildew growth. Many flooring materials, such as laminate and hardwood, are sensitive to moisture, which can lead to warping or other damage over time.

Finally, a level subfloor is necessary to prevent uneven surfaces that could affect the installation and durability of the new flooring. An uneven subfloor can create stress points that lead to cracking, bending, or other failures in the flooring over time. Therefore, prior to installation, taking these steps to ensure the subfloor's condition contributes significantly to a successful flooring project.

Addressing the other options: leaving the subfloor untreated for ventilation ignores the importance of cleanliness and moisture management, while installing additional layers of carpet can complicate the installation process without addressing potential underlying issues. Applying a thick layer of adhesive is also not advisable, as it may lead to improper bonding and other complications during installation.