Crown moving around

[langbeinite]

I recently had an integrity stainless flex liner, top flashing, rain cap, and insulation wrap installed as part of a new wood stove installation. After a few weeks of use, I noticed that my chimney crown had shifted a bit. After a couple more days of use, the crown has shifted as shown in the photo. It seems that when the chimney liner heats up, it is getting longer and pushing the crown around. Some questions:

• Is the chimney liner supposed to be able to slide a bit in the top flashing? The top flashing has a gear clamp to hold the liner, but the installer was overzealous and used silicone as well, so there's no hope of that happening.
• I've read many sources saying that a proper crown is supposed to have a bond break to allow for different rates of expansion between the brick and concrete, but how are you supposed to keep a crown in place? It looks like the mason who originally installed the crown used a bit of mortar around the edges only, but of course that didn't hold up well and now rain can get in.
• Any suggestions on what I should do now (beyond shifting the crown back in place, which I've already done)? This crown in undersized (but much better than most crowns in my area), so in addition to needing something to hold it in place, it also needs something to seal out the rain. Should I just silicone it in place? But if I do that without addressing the liner expansion issue, I'm worried that the liner will break the bricks apart further down. Is this fear unwarranted?

 

[EatenByLimestone]

Is that crown just metal, or is it concrete covered in metal?


Oh. I can see it better now. I’ve never seen a crown move like that.

 

[langbeinite]

The crown is concrete, with the top flashing siliconed to it.

 

[langbeinite]

I'm just realizing that what I'm calling a crown is just the bottom of an old concrete chimney pot. The installers cut the top half off of it. It has fairly thin walls, so it isn't particularly heavy. I'm sure that doesn't help, but I suspect it's not the only thing wrong with this setup.

 

[EatenByLimestone]

Is the brick just veneer? Those don't look like like full thickness bricks. I think I'd have someone come in to make sure the rest of the structure is solid considering water is getting in.

 

[langbeinite]

The bricks are standard thickness. The line you are seeing in the picture that makes you think they are veneer is the bit of mortar that was holding the crown/pot in place. The bricks are probably grey on top from smoke (from before the liner was installed). No water (or not much water) has gotten in yet because this issue just started, but the rain is starting tomorrow. So I'd like to do at least a temporary fix today.