Textured walls add visual warmth to a room as well as hide imperfections. There's more to applying texture to a wall than picking up a paintbrush. A variety of tools are used to texture walls, ranging from flat trowels and putty knives to slap brushes and spraying machines. Machine application is the fastest and allows you to apply an even layer of coating with several different styles, and you can also make additional styling manipulation after the spraying before the texture has a chance to dry.
The only real downside to spraying texture as opposed to applying it by hand is the mess. No matter how good you are with the machine, excess is sprayed around the room. Always cover anything that you don't want drywall texture to stick to, such as windows, trim work and if you are working in a livable room, the floor, furniture and other areas. Plastic sheeting is the best solution, taped up with masking tape.
There are two types of drywall texture sold at home improvement stores: pre-mixed and dry mix. Pre-mixed mud comes in buckets and boxes, but still needs to be mixed with a drill prior to using in the machine to ensure consistency and total mix. Dry mix solution first needs water added to it. It is best mixed in 5-gallon buckets with a drill and drywall paddle. Always add water according to the manufacturer guidelines. You are aiming for the consistency of thick cake batter. Anything too runny does not properly texture on the wall but tends to run.
The most common texture applied with a texture machine is the popcorn texture, which are fingernail-sized chunks of texture sprayed out of the machine nozzle that stick to the wall when they hit with the force of the sprayer behind them. The nozzle is adjustable and also applies what is known as orange peel texture, which are larger and elongated sections. Always test a scrap piece of drywall before applying to an entire wall so you can get a feel for the nozzle setting you desire.
Hold the nozzle in between 24 inches and 36 inches from the surface of the drywall. You'll know the rough distance that is best for your chosen application based on the test piece of drywall you sprayed earlier. Pull the trigger and spray the wall, evenly layering section by section according to the amount of texture and pattern applied by your nozzle selection. You can work floor-to-ceiling or ceiling-to=floor.
Further tooling may take place if you so desire. For example, a common texture known as knock-down texture is applied by running a flat trowel over the top of popcorn texture while the mud is still slightly wet, thus "knocking down" the tops of the popcorns and flattening them slightly. A paint roller may also be used, as well as a putty knife or brush if you are looking for the slap-brush technique.