Are you sure those aren't shadows from wavy drywall?

@Jill, I sure hope not, though I guess that is a possibility given what my contractor left me with on some of my vertical walls. What on earth am I going to do if that is the case?

I would buy floetrol and add to your final coat of paint. The new paints dry too fast, and causes streaks. Floetrol, keeps it from drying so fast, so you end up without streaks. Hopefully, thats all it is.

It seems too regular to be "streaks" but as has been mentioned might be lap marks from not keeping a wet edge.

I always paint perpendicular to the windows so light won't bounce against any lap marks.

Not sure if this is really it so not sure how to fix it.

Thanks for your thoughts @cat_ky and @JJ. It is quite hot so the paint seems to be drying as we go making keeping a wet edge seemingly impossible. The room is also quite large (22x28') so that isn't helping either. One "edge" of our 5x5 square stays wet and we lay off into the next square we paint, the other edge gets feathered as it has a little bit of time to wait until we get to the new row. Is there is a better way? I like the idea of the Floetrol. Is it compatible with any acrylic paint?

@JJ, if it isn't lap marks, what else can it be? I feel like I'll be screwed if it's indeed uneven drywall.

Easy way to test if it’s the paint or if it’s the drywall. Roll a couple of lines on the diagonal. If the lines are still like what’s there now, you know the drywall has buckled.

you don't need to sand walls between coats! that is more for painting wood.

Get a 1/2” nap. It holds more paint. What kind of paint are you using?

I'm thinking uneven plater, but at this point, you'd have to get someone to put on more and argue with the painter.

If it's hot and drying add the Flotrol ( works with latex ( there is also an oil version, don't use oil) use a 1/2 nap roller, matt paint, wait until it's cooler!

Hire a pro?

With two coats of primer plus a topcoat already those streaks shouldn't be there. Seem to me there's a problem with the gypsum ceiling. Adding Floetrol seems like your best option at this point. I'm sure waiting until cooler weather isn't really an option. If you do go ahead and apply the last top coat please let us know how it turned out. Good luck!

@Pam, thanks for the suggestion. If I roll a couple of lines on the diagonal and that rules out the uneven drywall, will those horizontal lines be visible afterwards?

I'm going to get the Floetrol and a 1/2" roller. Will also bring an a/c over and try and get the room temp down. Thanks @CC and @Steveworks LLC!

Kinda sick now at the thought of it being the drywall, not the paint job. Steveworks LLC, I'd love more than anything to hire a pro. Every "pro" I've hired to this point has left me worse off than when I started, so I've taken the painstaking DIY approach.

IMO one coat of primer and no sanding in between coatss and a smoother roller and go in one direction with the roller not back and forth. Make sure this is either ceiling paint or a matte paint. IMO you have sanded down to the tape with all the sanding .

Agree with above comments...why are you sanding between coats? Maybe destroying smooth surface.

I read to give the surfaces a light once over with a fine grit between coats. Nothing major and no real rubbing took place. I've sanded to the tape on a section of the wall when trying to level some uneven drywall, so I know what going too far looks like. I didn't see or feel anything untoward at the seams on the ceiling when doing my light sand and inspection. Wouldn't I have seen the tape? If it has buckled, as someone above mentioned, then maybe that would be harder to notice with my face pressed into the ceiling looking for minor imperfections? I can drop the sanding between coats, that is easy enough.

What kind of fabric rollers are best for the ceiling? Knit, woven, microfiber? My 3/8" roller was a woven one, but read a knit might be better for flat ceiling paint so ordered this high coverage 1/2" roller. However, all the 1/2" knit rollers say for semi-rough textures and I'm scared I'll texturize my ceiling and end up with a surface like this.

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what kind of flat paint are using? I would move up to a 18" roller and keep that wet edge

what kind of flat paint are you using ? move up to a 18" roller and keep a wet edge do you have help or is it just yourself

Thanks @Rockin' Fine Finish. Any advice for keeping a wet edge in a big room? At its widest and longest parts, the room is 21'x28'. We've been tackling it in 5x5' sections and moving upwards, but invariably, one of the edges of my square is dry by the time we get back down to the next row.

There are two of us, but my gumby arms can't last more than a square before they are on fire, so I stir the paint, move the spotlight, fill up the tray and bark directions when I think I see a spot that has been missed. Try to make myself useful. Truth be told, with the white on white, I really don't know what I'm seeing most of the time.

The paint is Behr Premium Plus Ceiling Paint from Home Depot.

How flat does the ceiling have to be before it starts creating shadows? I put a straight edge up there in different spots and it is certainly not completely flat.

is the ceiling textured or is it smooth? if the ceiling isnt flat it can give you shadows and variances. but most ceilings are ant super flat unless your house is newly built and you paid a premium. if it's a older home they will most likely not be flat unless plenty of work goes into making them flat

also doing small sections like that doesnt help I would hire this part out to a painting contractor

@Rockin' Fine Finish, the ceiling is smooth. It is a new dropped ceiling. New framing, new drywall. Still isn't flat, annoyingly. I got up on the ladder to have a closer look. Wondering if this is the root of my problems and not our painting technique (well some of it may also be technique).

Some of the lines seems to be coming from under the paint.

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Also, I was holding the flat edge, the camera and standing on the ladder so not the greatest picture, but one half of the straight edge was flush on the ceiling, the other end was nearly 1/4" off the ceiling. Is this enough of a variance to cause shadows? If this is a common problem, is there a painting solution around this other than trying to flatten out the ceiling?

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1/4 will do that the other picture looks like a drywall seam

@Rockin' Fine Finish Is there any way to make paint hide these issues?

no but rolling continuously across the ceiling will help with less streaks 1/4 is to much variance. is 1/4 in one spot or through out

@Rockin' Fine Finish, I went up the ladder only under a few spots where I saw the dark streaks to have a closer look (there are many more spots I could have checked). Some areas looked like lots of tiny little pits in the paint causing the darkness, but were relatively flat. The 1/4" variance I showed was the worst of the three spots I checked with the straight edge. I dare say I'd find more uneven areas if I investigated further, though I was feeling too disgusted to continue.

will probably need to be addressed by skim coating the ceiling where the variances are.

@Rockin' Fine Finish Oh man. I just can't catch a break with all the headaches my contractor left me with. Will the skim coat take me back to step 1? ie. will I need to re-prime the area twice, then two topcoats?

yes

Thanks for all the advice @Rockin' Fine Finish. I'm going to go cry myself to sleep now.

sorry hopefully you can find somebody to fix it

Thought I’d take a chance to see if the second top coat evened it all out. Marginally better, but really, it didn’t. However the 1/2” microfiber roller was definitely an improvement over the 3/8” white woven.

The dark spots appear to be texturized, rather than being spots that were missed with the roller. Can these little pock marks be filled with a thick layer of paint or is a skim coat of drywall compound the only solution?

Dont forget to use the floetrol, so you keep that wet edge, thats what this product does.

Looks more like a drywall problem than painting issue.

much better good for you on getting it done