I need help with crown moulding gaps

[Snattlerake]

This^

Those gaps do not look structural.

What do you mean by this?

FYI, I cut the two pieces on the 45 degree bias to keep from seeing the joint from the active area of the room. I used to do this with the overlaps on vinyl house siding.

 

[Catt57]

It sounds like the house is shifting causing the joint to move. Any kind of "hard" filler is not going to stay put in a joint that moves. You could try to find some sort of flexible filler, but if it is moving 1/8" or more then nothing may stay in place.

 

[chuter]

If you're like me, once you see something like that you can't stop noticing it.

Just stop looking at it.

 

[SlugSlinger]

What do you mean by this?

FYI, I cut the two pieces on the 45 degree bias to keep from seeing the joint from the active area of the room. I used to do this with the overlaps on vinyl house siding.

I mean they are not developing because of an underlying structural issue. It’s cosmetic.

 

[swampratt]

I had a friend that had a crack 3X larger than what you have and it kept coming back he tried all kinds of stuff in cans and tubes.

I told him try elastomeric sealant and that fixed the issue 3 years later it still looked excellent no crack.

Regular caulking dries hard and will not stretch and you can't keep that joint from stretching in Oklahoma.


DAP Extreme Stretch 10.1 oz. White Premium Crackproof Elastomeric Sealant-7079818715 - The Home Depot

 

[John6185]

It would seem to me that if the cuts were mitered at 33 0r 45 degrees that shrinkage and expansion would not be so noticeable when they occur.

 

[SlugSlinger]

That is some stretchy stuff!

Stretches 600% for a crackproof finish

I had a friend that had a crack 3X larger than what you have and it kept coming back he tried all kinds of stuff in cans and tubes.

I told him try elastomeric sealant and that fixed the issue 3 years later it still looked excellent no crack.

Regular caulking dries hard and will not stretch and you can't keep that joint from stretching in Oklahoma.


DAP Extreme Stretch 10.1 oz. White Premium Crackproof Elastomeric Sealant-7079818715 - The Home Depot

 

[swampratt]

I worked in a warehouse and the concrete roof beams would move 3" during the day.
Amazing how much something can expand and contract

 

[OkieJoe72]

Recommend trying Big Stretch caulking. I’ve used it primarily on exterior surfaces, but it does a good job and holds up well over time.

 

[SlugSlinger]

I’ve used this to seal popped driveway chips and expansion joints where I removed rotted cedar boards. This stuff is amazing and uv rates, but it also says good for indoor use.

https://www.emisupply.com/catalog/product_info.php?products_id=66113
That was a lot of caulking!