How to keep drywall cracks from reopening?

Here's a link that deals with drywall cracks that come back. It sounds like you need a flexible patch.

https://www.popularmechanics.com/home/interior-projects/how-to/a18077/how-to-fix-drywall-cracks-for-good/

You need a super-flexible material and one that can bridge a wide gap. I've used DAP ElastoPatch with good results. The material is about the consistency of yogurt, and you can apply it with a 6-inch joint-taping knife. Although it's pretty simple to use, it'll take you a few tries before you can produce a smooth finish. I'd recommend experimenting on a cast-off bit of drywall first.

Before you patch, use a painter's 5-in-1 tool to rake out the former repair materials. Then scoop out the patch and spread it on in thin layers. Wipe off any excess (you won't be able to sand it down like joint compound), let the patch dry, then paint. Big stretch works well. If the cracks keep coming back and doors are not closing properly it is foundation problems. You may need to get a contractor out to check your foundation. i Had mine fixed many years ago.

You need to use drywall mesh tape over the crack first. Sticky side on the wall. Then use a drywall patching compound over the mesh. I like to use a no shrink patching compound. You do not need to open the crack in drywall. If it's plaster over lathe then the crack needs to be opened slightly. Dampen the crack with a sponge, cloth, or paper towel. Do not wet it. This will prevent the old plaster from absorbing moisture from the patching compound. Mesh tape over the crack and then the patching compound.

Here are some possible reasons why you are getting these cracks:

What Causes Drywall Cracks?

Drywall cracks can occur due to stress from excessive moisture, reasonable foundation settlement, or legitimate foundation damage. Drywall cracks can appear as vertical or horizontal cracks. Vertical cracks are relatively harmless, while jagged horizontal or angled cracks can be a sign of foundation problems.

These facts don’t address a more serious question – why does my wall keep cracking?

Drywall Cracks that Keep Coming Back

When a drywall crack keeps coming back, even after you’ve attempted to repair it, there are likely underlying foundation issues. These issues could be caused by:

• A void under your concrete slab
• Soil erosion around your house foundation
• Landscaping around your house foundation that is causing root or water damage
• A foundation soil type that dramatically expands and contracts with moisture changes
• A leak under your concrete slab that is causing foundation shifting

ref:https://uretek-gulfcoast.com/how-to-fix-drywall-cracks-keep-coming-back/

Other Hometalkers have suggested some effective ways to repair your walls.

Hi Marion, i hope this video helps you out, it explains why the crack keeps coming back

https://www.youtube.com/watch?v=CqNed8f-cys

I'd recommend experimenting on a cast-off bit of drywall first. Before you patch, use a painter's 5-in-1 tool to rake out the former repair materials. Then scoop out the patch and spread it on in thin layers. Wipe off any excess (you won't be able to sand it down like joint compound), let the patch dry, then paint.

Anyone have a flexible patching product that they things works best?

Hi, Use an expanding filler and when dry sand it down.

House settling with cause issues of cracks. If you have any geological events, they will make it worse. Your best bet is to sand down, tape, and finish.

Yes, a mesh over the crack will help. If you can find it, which might be tough as it could be discontinued, but Goodbye Cracks solved all my issues. You could maybe try Flex Seal -- read the can first.

The joints need to be re taped

Yes. This will be the second time. Will follow some of the good tips. What an aggravation.