What Knockdown Texture Actually Is
Knockdown is a drywall texture where you spray on a splatter pattern, wait for it to set up slightly, then flatten the peaks with a drywall knife. The flattening is the "knockdown" part. You end up with a mottled, organic-looking pattern that hides wall imperfections pretty well.
It was big in the 70s and 80s, which is why half my house has it. My neighbor Dave has it too. So does pretty much every house in my subdivision. If you've got a house from that era, odds are good you're looking at knockdown somewhere.
The pattern has randomness to it, which is actually good news. Unlike something like skip trowel where every stroke shows, knockdown is forgiving. You can get close enough that nobody will notice unless they're looking for it.
The Tools You Need
Here's what I bought that first time, and what I actually use now:
A drywall texture hopper. Mine cost $40 at Home Depot. It's basically a container that holds drywall mud with an air hose connection and a trigger. You hook it to a compressor and spray. Uncle Frank has some professional spray rig that cost $300, but for occasional repairs, the $40 hopper works fine.
An air compressor. I already had one for my nail gun. You need at least 40 PSI. Mine runs at 90, which is more than enough.
A 12-inch knockdown knife. This is just a wide, flexible drywall knife. You can use a regular 10-inch knife too. I paid $8 for mine.
All-purpose joint compound. Not the setting type, the regular premixed stuff in the bucket. Runs about $15 for a five-gallon bucket. You won't use nearly that much for a small repair, but the bucket lasts forever.
Total investment was about $65, not counting the compressor I already owned. Cheaper than paying someone, and I've used this setup probably eight times since then.
Getting the Mud Consistency Right
This is where I screwed up the first time.
I loaded the hopper with mud straight from the bucket. It was too thick. The splatter came out in globs instead of that even spray pattern. It looked like someone had thrown oatmeal at the wall.
Pete at the hardware store had told me to thin it. "Add water until it's like heavy cream," he said. I thought I knew better. I didn't.
The right consistency is thinner than you'd expect. Take a scoop of mud, add water gradually, and mix until it drips off the mixing stick slowly but smoothly. If it plops off in chunks, too thick. If it runs off like water, too thin.
Uncle Frank has this test where he dips his finger in and holds it up. If the mud runs down slowly, like cold honey, it's ready. That's the best description I've heard.
The Actual Technique
Before touching your wall, practice on cardboard. I taped a piece of cardboard box to the garage floor and sprayed patterns until I could get something close to my existing texture. Took about fifteen minutes and saved me from another do-over.
Here's the process:
Spray a section about two feet square. Don't try to cover the whole area at once. Keep the hopper about 18 inches from the wall. Move steadily. The splatter should create peaks maybe a quarter inch high.
Wait. This is critical. You have to let the mud set up but not dry completely. In my garage in summer, this was about 8 to 10 minutes. In winter, more like 15. The mud should be firm enough that it doesn't smear when you touch it lightly, but soft enough that it still flattens.
Knock it down. Hold the knife almost parallel to the wall and drag it lightly across the peaks. You're not pressing hard, just skimming. Each pass flattens the high spots and creates that characteristic mottled look.
Let it dry completely before judging it. Wet texture looks different than dry. My first attempt looked terrible wet, and pretty decent after it dried overnight.
Matching Existing Texture
The hard part isn't the technique. It's matching what's already there.
My garage walls had a medium knockdown. Not super heavy, not light and subtle. I needed to match that exact density. So I sprayed test patches on cardboard, adjusting my spray distance and hopper settings until the pattern looked right. Closer to the wall makes bigger splatters. Farther away makes finer ones.
The knockdown timing matters too. Waiting longer before knocking down leaves more texture. Doing it sooner creates flatter sections. My existing walls had been knocked down fairly flat, so I learned to wait just until the surface skinned over, then knock it down while it was still pretty soft.
Feathering into the existing texture is the last trick. When you spray near the edges of your repair, overlap slightly onto the existing textured area. This hides the transition better than a hard line where new meets old.
Dave tried to match knockdown in his hallway last year and he skipped the overlap. You can see exactly where his patch is. The line is subtle but it's there. He says he doesn't notice it. His wife does.
What I Learned the Hard Way
That first repair, the one I scraped off and redid, failed because I was impatient. I sprayed too much too fast, waited too long to knock it down, and used mud that was way too thick. It looked like stucco. Terrible.
Scraping off fresh texture isn't fun. I waited until the next day when it was fully dry and used a wide scraper. Took an hour. Then I had to skim coat the area again, sand it, and start over.
The second attempt went much better. I thinned the mud properly, practiced on cardboard, sprayed smaller sections, and knocked down at the right time. The match isn't perfect, but Sarah walked by that wall a dozen times before I pointed it out. She said she couldn't tell which area was new.
That's the standard for texture matching. Not perfect. Just invisible to anyone who isn't looking for it.
When to Call a Pro
I've done maybe a dozen knockdown repairs now. Small patches, I handle myself. But there are situations where I'd call someone.
Ceilings over 10 feet high. My hopper sprays sideways fine but overhead is awkward, and getting even coverage on a high ceiling while standing on a ladder sounds like a recipe for disaster.
Whole rooms. If you're texturing an entire room after new drywall, the pros work faster and more evenly. Brother-in-law Jeff tried to texture an entire basement himself during his house flip. The pattern varies visibly from wall to wall. You can see where he got tired toward the end.
Anything with a tight deadline. Texture repairs need drying time. Rushing means visible patches. If I have guests coming in two days, I'm not starting a texture project.
For regular repairs though, a patch here and there, the $65 in tools has paid for itself many times over. Carlos, my painter friend, told me he'd charge $200 minimum to texture a small patch. That's four small repairs before the hopper pays for itself.