How to Apply Knock Down Texture

Overview

Ceilings are notorious for showing flaws. Light shining across that large, uninterrupted surface accentuates every pockmark in the dry- wall mud, every little ridge left by the paint roller.

The usual way to mask these troubles is to spray on acoustical “popcorn” texture. But I go with a “knockdown” texture on most ceilings, whether they're new drywall, old plaster or a repaired ceiling of any type. The beauty of knockdown texture is that it not only hides imperfections but also creates a more subtle look than heavier textures. A typical ceiling takes less than an hour to texture and costs less than $20 in materials. Best of all, it's almost impossible to get wrong—as long as you follow a few simple steps. To spray on the texture, I use a small electric texture gun. But gun powered by an air compressor will work just as well.

Prep the room

You can wipe up a texture mess with a wet rag, but preventing a mess is a lot faster. Remove all furniture from the room, as well as floor coverings, light fixtures and wall hangings. I like to cover the floor with rosin paper instead of drop cloths because I can roll up the entire mess at the end of the job and drop it straight into the trash. I over- lap each course of rosin paper about 6 in. and tape the seams.

Next, mask the top edges of the walls with 1-1/2-in. masking tape. Press the top half of the tape in a straight line along the top of the walls, just under the ceiling line. To the bottom half of the tape, adhere inexpensive 0.8 mil plastic drop cloths, “bagging” the entire room.

Paint now, or later

You can apply knockdown texture to bare drywall and paint over it later. But I prime and paint the ceiling first, then texture it and leave the texture unpainted. The slight color contrast between flat white ceiling paint and the off-white texture gives ceilings a nice dimensional depth. As a bonus, I don't have to sweat lap marks or flash marks when painting. The texture will hide those imperfections. Depending on the humidity, the ceiling can be ready to texture in as little as three hours after painting.

Mix up the mud

I add about 2 in. of water to a clean 2-gallon pail (an ice cream pail is ideal) and mix unaggregated texture powder into it. For knockdown texture, never use mix that contains aggregate. Continue to add water and powder until you have a bit more mix than you think you'll need. Approximately 1-1/2 gallons of mix is adequate for a 10 x 14-ft. room.

Here's a crucial step: Set the mix aside for about 15 minutes to allow for complete water absorption. Otherwise, the mix will thicken in the hopper. It won't spray and you'll have to clean it out and start over. After this “slaking” period, add a bit more water and remix. The final consistency should resemble pancake batter. A mix that's too thick won't spray well, so it's better to error toward a slightly thinner consistency.

Practice, then spray

After filling the hopper, I spray a test pat- tern on the wall plastic. Since months may pass between my knockdown projects, I have to relearn the feel of the spray gun. My goal is to achieve roughly 40 percent coverage. A knockdown finish depends on leaving about 60 percent open space so that the splatters can be “knocked down” to create the desired effect. I use a coarse or medium tip for my splatter application.

After my test run, I spray the ceiling. Spraying an average-size room takes less than 10 minutes. Hold the gun about 18 in. from the ceiling and work in blocks about 3 ft. square. Try to avoid overlap where these blocks meet, but don't worry about a little overlap.

Do worry about too much coverage: Keep the gun in motion to avoid spraying any area too heavily. Knocking down the splatters later will greatly increase the area that the mix covers. So it's better to go with lighter coverage than heavier.

If a room is larger than 225 sq. ft., I only spray and knock down half the ceiling at one time. That prevents the mix from drying before it can be knocked down.

Knock down the splatters

There are really only two ways to spoil a knockdown texture: too much splatter coverage and waiting too long before knocking down the splatters. When the splatters become too dry, you just can't knock them down smoothly. So keep a careful eye on the sheen of the splatters. As soon as the wet shine disappears from the first area you sprayed—usually after 10 to 15 minutes—get moving.

To knock down the splatters, I use an 18-in. rubber squeegee-style knock- down knife ($14). There are metal versions, but I find the rubber blade easier to use. If you don't find one at a home center, search online for “knockdown knife” to browse a huge selection. Screw an extension pole to the knife and you're ready to go. Here's how to do it:

• Work across the ceiling in courses, overlapping each course by about 3 in.
• Complete each course in two passes. Start at one edge of the ceiling and stop a few feet from the wall. Then drag inward from the opposite edge to finish the course.
• Work across the ceiling joists. If you drag parallel to the joists, the knife might bridge troughs between joists, leaving some splatters untouched.
• Steer the knife in a straight line. Any swerves or curves in the line of travel will be noticeable on the finished ceiling. Run right over electrical boxes and recessed lights. Don't veer around them.
• Keep a damp rag in your hand, and wipe the mud buildup off the knife after every pass.
• That's it. By the time you're done washing up your tools, the texture will be dry enough so that you can tear the masking tape and plastic off the walls.