Either come to terms with the fact that you will have to repaint, or get very handy with painter's tape!

Sure the walls are wavy, but that looks like a poor installation job.

It sure does those weren’t nailed in properly

You don't see the whole picture. It's like a foot long deep dip in the wall that ends right outside the picture frame... I can't tuck every foot of molding perfectly flush, it's not that flexible... Let's just not... Please... Don't... I just asked for a caulk advice. Please.

You are asking for a magic bullet. The answer is to caulk as necessary and then repaint. Sorry, don't shoot the messenger. Also, those are really large gaps to fill with caulk. Further, if those are wooden crown moldings, expect movement and cracks in the caulk as the seasons change.

All the caulk needs to be painted over. I would use white caulk, paint the trim, tape off the trim, then paint/touch up the walls and ceiling.

IMO if you knew the walls were that off you should not have chosen molding at all. There is no way those caulked gaps will stay filled .

There are ways for a really cracker jack trim carpenter to compensate for such situations. Unfortunately, you did not have one :(

When you post in a public forum, you don’t get to choose who responds with what answers

You want to fix the butcher job with caulk. I’m not the first to tell you it’s not happening.

Caulk only hides so much sin. You need to find someone who knows how to install crown. Whoever installed the crown had not a clue.

I think people need to be more civil to each other. The OP might have installed that crown him or herself -- how would you like to be told it is a butcher job, even if mistakes were made?

The very big gaps, I would skim coat and feather the walls...(yes I have done this myself. It was acceptable but would have looked very very good if I had the money to hire someone).

We have molding over a textured wall (equally as difficult to get a straight line) and I approach it like this:

Caulk and use one of the corner caulk tools at Home Depot to minimize excess.

Where the molding has an outside CORNER then the parallel surface to the wall is the one that gets the tape stuck to it because there's a nice crisp edge there, and the perpendicular one gets painted the wall paint..baseboard and ceiling both treated the same.

Moldings that are rounded closest to the surface, won't work with this method, but if you had to, you could run a strip of painters tape along the molding close to the wall, but still on the molding.

Use frog tape. Far superior.

Pennydesign, thank you. Will save your advice as the last resort though, I considered that before but it would require some time investment which I'm short of. I've done one room so far by simply caulking the cracks and painting over with the wall paint. Looks alright to me so far. Who on earth pay attention to trim lines anyway in other peoples houses? From experience I know I forget about these things in a week and never notice them again.

The other ten ones who "contributed" to this thread... Well, I should've known better than posting on the forum. 10 replies with nothing but crapping on my work. I don't know what I was thinking asking a serious question here... I read other threads and most of them go like this... someone asks for advice and 25 perfectionist "pros" jump in and start crapping over everything they but never contribute anything remotely useful, just a bunch of armchair wannabe remodelers that probably never lifted a hammer and just judge everyone and everything. The lady with the tag "PRO".... I would fire you on the spot if you told me "you shouldn't have chosen molding at all" and your business would be blacklisted for good, this is the biggest nonsense I've heard from anyone, ever. I know your type, can't do anything, all excuses and no go. I bet your consulting involves going around places and just overcharging poor souls for "consulting" on what they can NOT do. I don't know why you have "pro" sign next to your name, you're no pro by any stretch of imagination, no pro would burp this nonsense like you did here without asking more questions about the nature of the project. But even then... if you can't figure out a way around such a simple issue that even a 10 y.o. would, you should've be in this business.

John Watson, thank you. I'm doing it myself with my friend, he's a handyman and I'm just a homeowner with minimal skills. It's a tiny old crooked house, and we're doing quick work of prettying it up but on a pretty much minimal budget, so not looking or expecting a perfection, and I have very little time to spend on this, definitely not spending hours on something as like trims gaps, haha. As long as it doesn't jump in your eyes (and it doesn't), all is good in our book.

No problem nuieve, good luck on whatever solution you end up using.

nuieve, you've learned a lot and thats always valuable. my general advice, going forward, is to not highlight that which isnt perfect without a strategy ahead of time on how to make it close enough to perfect to suit you.

ignore the tone of 'rude people' but not their advice.

I've successfully filled a gap like this in an older home, although did have to re-caulk periodically. Make sure you don't try to fill the large open spaces with one application - it may take several to build up the amount needed for a smooth "final" line of caulk. Match the caulk to your trim - if you do a good clean up while you are caulking, you won't need to retouch the paint on the walls.

"Sure the walls are wavy, but that looks like a poor installation job."

"There are ways for a really cracker jack trim carpenter to compensate for such situations. Unfortunately, you did not have one :("

These participants ^ have obviously never installed crown molding. Because it triangulates between the ceiling and wall, mathematically it's a 6" wooden block which doesn't bend to wavy walls.

This is too much deviation for caulk. Float some mud on the wall, please.

Good grief. Maybe we need to take sensitivity training so we don’t hurt anyone’s feelings.

Here is a video that may help you...about scribing the molding to follow the contour of the molding. Yes, its extra work but old houses always are.

There are other work arounds too if you google...adding flat stock, filling in with plaster etc.

lots of videos on youtube for DIYers so make use of them. I went from not knowing how to paint to being able to rehab an entire property solo.

scribing crown

"Cork", the trim carpenter's friend. If you caulk it, use painter's caulk and a damp cotton rag to clean up any blobs. Don't use any paper towel, which will shred. You'll have to make multiple passes or use backer rod in some of the larger gaps. If you want, use tape to give you a clean edge with the caulk and maybe you won't have to touch up.

Go online and find some trim caulking tutorials, that may also help.

The easy route is to add more trim. Sometimes a lot more trim. A thin flexible one, below on the wall, and above on the ceiling. Like s piece of lathe molding. And some quarter round. The flex of the small molding will hide more gap. It will float in snd out. The multiple horizontal lines will help fool the eye. Once the smaller gap is caulked properly, and the whole thing painted properly, it will look a lot better.

The really bad walls need mud and floating though.

And if this is an older modern style home like a Mid Century Modern, or Late Century Contemporary, then NO molding would be the appropriate choice.

An upside-down shoe moulding will work. Good idea, Sophie!

But even though you add another trim to wouldn’t that have gaps too since walls aren’t straight

Yes, but narrower trims are more flexible so they bend with the wall...

Nothing changes really...it's all just a case of trying to fool the eye enough to be able to live with it.

Caulk will work...and tape. The main objective is a straight visual line where the paint colors change, it’ll be tedious, but you can do it!

I still don’t understand how the walls aren’t straight....is it the plastering or not enough framing support.

Claire:

It's because wood grows on trees. Frame with steel and you'll never have this problem.

lol....that is funny

Sound good. That method works for me with my "perfect" walls, also because it give you that nice crisp edge that you can't get when trying to tape in the middle of a caulk line...

Joseph Corlett:

I have to beg to differ about the steel framing. I had a friend who owned a modern condo with tall ceilings in the living room. Not only could you sight down the wall and see the waviness of it, but you could also press in on the wall and watch the wave move across the wall when you let go! Of course, that was more the fault of shoddy construction than steel itself (kind of a McMansion condo building).

I have a few steel-framed walls in my house and I hate them. I hate the metallic creaking noise they make and the fact that they feel and sound flimsy. Give me wood any day.

Nuieve-

I know you're done now, but a weird idea popped into my noggin! If the caulking ever separates, or fails in some way..... maybe a square or rectangular profile rubber/dense foam could be pressed up into the gap?!??! The bottom edge of this would obviously be parallel to the floor, but would move with the wall & crown easily. Bottom surface could maybe painted the wall color, since the bottom line of the moulding is straighter. In a way, you'd be painting the exposed side (the down-facing side) of a refrigerator-gasket! :-)

Again....just some "outside the box" thinking! This could be your plan B option! ;-)

Faron

When having to square off caulking, I usually use fresh, sharp edged plastic putty knife. The plastic does not leave metal scuff marks on the wall or other surfaces.

Another "too late" thought....?

For THIS particular job, regular painters-caulks usually fail too soon. A little more specialized caulk for this use is the Big-Stretch line. When cured, it's paintable, & handles large movement, assuming clean substrates. I used it many times, even in normal small "painters-caulk" situations.

At home, I caulk my vertical inside corners, on top of base-trim, & along the wall/ceiling joint. Built in '96, our home has a really good sheetrock job. I'm damn fussy tho'.... :-)

Faron

Faron, that's the backer rod I was referring to. Thanks for mentioning the Big-Stretch caulk, I'll have to look for that.

Cool CKB!

Most all caulking backer-rods are round, making its use HERE a little tricky. SOME specialty foam insulation is square or rectangular. A few are the closed-cell foam-rubber type, & would hold paint.

I should've noticed this thread earlier!!! Now however.....it's devolved into just another "HELP ME CHOOSE A COLOR" forum under Houzz, so I only check in occasionally.

Faron