Flex liner top plate question

[esh21167]

I have my insert (sitting in my living room) and am just about ready to buy a liner for my masonry chimney, but have one last (I hope) question about the liner kit I'm having trouble getting a solid answer on.

My brick chimney holds the terra cotta flues for both the oil burner and the fireplace. The distance between the two flues is only about 4". The wash/crown is tapered, high between the two and lower at the outer edges. The terra cotta on the fireplace side extends only about 1/2" above the mortar near the center of the chimney and about 1 -1/2" on the outer edge. I originally thought about getting a terra cotta top plate, but I don't think there is enough flue exposed for the cap to fit over and sit flat.

So, will a standard flat top plate sealed to the top of the terra cotta flue be secure enough to support a 6" diameter x 25' long liner? Building up the crown is an option, I suppose, but will screws hold the top plate in the mortar or does the hi temp sealer do most of that work? Any insight on options is appreciated.

The closer I think I am to installing my insert, the more information I find I need. Hopefully I will get everything in line and be ready before the cold weather comes.

 

[BrotherBart]

Both of my chimneys have exposted tiles and I just sealed the flat top plates to the tiles with a thick bead of silicone and trimmed around the edges of the plates. They hold the liners up just fine. Both when burning and when dragging the chimney brushes down them. One liner is 25' and the other over 30'. They have been in there a couple of seasons now.

 

[esh21167]

Thanks BrotherBart! That's what I was hoping to hear. Makes things easier.

 

[Patapsco Mike]

The liner isn't really held up from the top. Mine is supported by the stove itself at the bottom and also by the way it bends to go through the inside of the chimney. They are more rigid than you might think. The only thing my top plate does is seal off the flue and keep the pipe centered. It isn't holding any weight at all.

 

[gpcollen1]

I had barely enough tile to secure the screws to so I used enough silicone/sealant to secure it and got the screws a bit tight. All held like a charm.

 

[pulldownclaw]

My liner had a hard lean to one side of the clay top making the stainless steel top plate lean also, so I drilled some pilot holes on the top and used tapcon screws to hold it down flat, as well as some silicon to seal it up.

 

[CK-1]

Used silicon on the top plate and clay tile. It's held down by the rain cap..