Knockdown Over Existing Paint?

Hey guys, couple of questions about the current project going on the home-front right now. First off, this is my house not a customers so it ain't gotta be perfect. That being said I'm a perfectionist and am more than willing to do it right.

I'm painting the new to us house prior to moving in. The drywall is (imo) pretty rough shape. Nail holes galore, multiple diy re-paints complete with runs/drips everywhere, etc. If i wanted flat/smooth walls there would be tons of skimming involved. The wife and I both agree that a knockdown finish is acceptable and probably less labor. All rooms that would be textured are flat except for the master which is an eggshell/satin.

I have access to a hopper gun setup but for a whole house I am considering renting a spray rig. Right idea? Do I need to prime prior to spraying the texture? Can the walls be run over with a pole sander? What method do you guys use over existing paint? Any tips, ideas, warnings very much appreciated.

If it matters, the new paint is SW MasterHide low-lustre. I intend to use tinted primer prior to painting.

In doing repairs and patches, I've never had a problem with texture sticking to painted surfaces, so I wouldn't worry about any special prep other than to vacuum the walls well to get rid of any dust and loose surface debris. If there is any damage, nail holes, etc., to fill or repair, do that as well, followed by a final vacuum.

When you spray the texture, go with topping compound that's been thinned just enough to make it flow through the gun/hopper. The premixed compound is smoother and won't have any dry balls in it, unlike trying to mix the powdered texture in a bag.

Yeah, I figured a thinned pre-mixed mud would probably be the way to go. Spray rig or hopper? Coverage rate guesstimates?

I've never used a spray rig, only a hopper and air compressor. The major difference between the two is a hopper you carry the weight, a spray rig holds the mud and you just wave a hose and nozzle around. Other than that, I don't know.

Spraying knockdown over paint is tough. Well the spraying part is easy enough, it's the knockdown that is hard. It always wants to slide, so you don't get much texture out of it. When spraying over drywall, the mud soaks in just a little. Makes it a lot easier. But you don't have that advantage. If you are going over flat paint, and you said most of it is, you'll be better off. You might want to prime the room that is satin finish. About the hopper compared to a spray rig. A hopper does a fine job. Probably not worth renting a rig. I'd still go with the bag mud that is designed for knockdown. Just mix it kinda stiff the day before and put a little water on the top. Soaks the lumps out. It stands up better, doesn't shrink as much. And since it is made for texture, it doesn't have the air holes in the finished product from thinning like the premix does.

The biggest issue will be dry-time differences between painted and patched areas causing visible differences in the texture. If it were me, I'd prime all the walls and ceilings.

I was afraid somebody would say that.....sheesh that's gonna suck. Prime before texture and after...correct? I'm gonna spend more in primer than paint

If you want to do it right, prime before and after. Use a bonding primer like grabber. I have not rented a texture machine before but, if it is not too much, I would go for it. Holding that hopper can get heavy after awhile.

The trick is knowing how to use it. Fill it and start at the floor and work your way to the top of the wall. By the time you get to the top it's not too heavy at all.

Another tip for the OP, you can control the texture size in two ways, by changing the nozzle diameter and by controlling pressure. Do some practice spots after you're set up and ready to go to get the feel of the texture unit and the tip/psi settings. Play around with things a bit until you get what you're looking for. You can practice on your wall and just wipe it down afterwards with a wet rag for a clean slate or use a scrap of plywood or drywall and throw it away when your done. I mentioned vacuuming earlier. Make sure you vacuum up any debris/dust on the floor that will get blown up and onto the wall. Same goes for window ledges, etc. Tarp everything off with blue tape and painters plastic. Have a hose and clean up buckets at the ready before you start spraying. Texturing isn't all that difficult, but I would recommend starting in a back room until you get the hang of it.

Thanks! All great tips This is exactly the kind of stuff I'm after. It's like all of our trades...if you do it every day you learn the quickest, easiest ways to get he best results. I'm all about working smart not hard

You are welcome.

I agree 100% spraying over paint can be tricky and very slick if ur trying to cover old ruff drywall be carefull the texture likes to slide down the wall very easy priming helps this but everything still has to dry outward not soak in so ur set time is gunna be a while also he's right we always let our dry mix sit overnight to get all the dry clumps out we leave it stiff for the night than thin to your likes when ur ready kinda pulls it like taffy

A way around that is to spray a very light coat on the wall and let it dry, then come back and give it the money shot. The light coat will give the second, heavier coat something to stick to.

Just another thought. Covered up lots of hundred year old plaster. Switched years ago to lite weight joint compound thinned with ZILZ rather then water. Never a problem. Not as fussy as dry mix texture.

Yup also another good method would also make his knockdown come out way more consistent personally we avoid knockdown when possible just a nice light dash and were out hints the prime coat so it all dries out nice and even

Orange peel is certainly much faster and easier, but I personally think that it has a bit of a "cheap" feeling to it. Just my opinion, of course, what's important is what the client likes.

Ya true it's funny how diff things are in diff areas round here knockdown is a dated look we do lots of trowel finished textures skip trowel and what not only knockdown when repairing older homes gramps and dad did many moons ago I agree tho orange peel is a cheaper look

See there, I'd never consider skip troweling in residential. I've seen it and done it, mind you, but it's too "industrial" because that's what you see in all the commercial buildings. For me, it's also a PITA to do and I hate watching my drywall guy make it look so easy! LOL

I feel the same way about radius corners as I do about orange peel texture. It's not that it can't be elegant and very nice, but most of the time it just cheapens the look and feel of a house. In high end homes it works, in Joe Average's $200K cookie cutter tract box, not so much.

I would hire somebody to skim the walls for you. You will be happier in the long run.Use good flat or satin paint too.

I don't care for knockdown walls. too gaudy on walls and dated. May hurt resale down the road.

Hire a pro.

One of the pros that I work with has a different approach to this. He shoots on multiple coats of orange peel, then uses his PC drywall sander/vac combo to bring it back to a smooth surface. It works great, and it's nearly all "machine work".