Builders sometimes use heavy stucco or popcorn textures to cover low-quality or incomplete finishing because texturing is comparatively inexpensive. High-quality drywall finishing requires several coats, each applied by workers with much experience. Applying texture requires a worker who can spray texture evenly across a surface, a skill that a long time to develop.
Applying heavy texture to drywall hides rough surfaces, so you can use texture to hide surface problems on your garage ceiling. Because heavy texture cannot seal the seams between boards of drywall, the safest approach is taping and floating the seams before applying heavy texture.
Building codes often mandate sealing gaps in garage ceilings and walls, including drywall seams. Gaps around hardware, such as garage-door support brackets, also require filling. Contact your local building department to find out if spraying heavy texture over drywall instead of taping and floating the seams is permissible.
Safety is the major reason building codes require sealed gaps. Gaps in walls and ceilings allow fires to quickly move through a structure. Fires are more likely in places that contain flammable materials, such as gasoline that might be stored in a garage. In addition, fumes from cars, stored fuel, paint and chemical cleaners can leak into your home if your garage ceiling has wide gaps. If your garage is unheated, gaps in the ceiling allow the passage of hot or cold air, causing energy loss.