If your premixed drywall mud is dried out or has begun to set in the bucket, you may be able to revive it by adding warm water and stirring. However, the first and most important step is to scrape off any hard, dried bits of drywall that may have accumulated toward the top of the container and throw them away because they will not easily reconstitute back into the drywall mud mix.

Furring strips, thin strips of wood or metal, are not always required for ceiling drywall installation. If the ceiling surface is even and in good condition, drywall can be directly attached to the ceiling joists using screws. However, furring strips become essential when dealing with irregular surfaces or when additional insulation or soundproofing is needed. They create a level substrate for attaching the drywall. Ultimately, the decision to use furring strips depends on the condition of the existing ceiling and the specific requirements of the project.

A common cause of separation between a wall and the ceiling is truss lift—this can happen to the ceiling of rooms directly under the attic when the seasons change and wood building materials dry out, shrink, and shift. Roof trusses often dry out at different speeds, and if the bottom pieces dry out faster than the top pieces, they can shrink and pull the attached drywall away from ceilings and walls, causing cracks. Fortunately, truss lift is only a cosmetic problem, not a structural problem, and you can fix it by separating the ceiling drywall from the roof trusses, and patching the cracks.

There are six levels of drywall finish, from 0 to 5, that refer to the amount of work performed during the finishing process.

Level 0: Drywall is hung with no finishing work.

Level 1: Tape is placed over the seams between drywall sheets.

Level 2: A thin layer of mud is applied over the tape and screw holes. This level is common for utility rooms or walls that will be covered.

Level 3: A full coat of mud covers the screw holes and tape, but the surface is not sanded. This is often used in garages.

Level 4: This is the most common finish for visible interior walls. It involves applying two coats of mud over seams and screw holes, with sanding between each coat, creating a smooth surface ready for flat paint.

Level 5: This is a high-end finish for luxury homes. It includes full taping, mudding, and sanding, plus a final skim coat over the entire surface before painting.