(Another) Help w/ Block Off Plate

[delp]

Greetings,

I'm trying to evaluate whether an imperfect block off plate is still worth it.

What I mean by imperfect is that the inside of my chimney is completely unsymmetrical --the masons who layed and parged those bricks over 100 years ago were not anticipating the installation of an unforgiving piece of sheet metal...

I've made a cardboard template and also one made of thin sheet metal. What I'm seeing is that it's going to be nearly impossible to get a tight fit around the outer edges that meet the brick as well as around the pipe, although the latter, seems more promising.

So, your opinions will really help me figure out whether or not moving forward is worth it.

Here's the question:

Is a block off plate with a bunch of gaps jammed with Roxul and sealed with a Hi-Temp sealant still gonna do what a block off plate is meant to do.

And another question:

If the project is still worth it, what's a good H--Temp sealant? The block off plate will be approx. 12"-14" above the stove, an 13NC.

Thank you!

 

[Jags]

Get the metal as close as you can and use an oversized piece of insulation. The insulation will kind of "wedge" itself into position. The metal is just insurance that it stays there. I am not sure that using sealant will buy you anything.

 

[delp]

thank you, jags

 

[Ashful]

Perf angle anchored around the perimeter, a sheet of steel sitting on that, and insulation filled in above. The steel's primary job is holding the insulation up. Worked well enough in my chimney, which was already 140 years old before yours was built!

 

[delp]

HaHa, Joful, you old chimney, you!

That's a good idea and pretty much what I did to build my floor level hearth...but that's another old thread. It would work to fasten angle but only on three sides. The bricks on the front of the chimney are placed vertically with a keystone-like wedge in the center, which means I don't have a mortar line at the same level as the other sides. Also I have very little room to maneuver around with only about a 10"

I think that after all the templates I made I might as well make the real deal and just stuff Roxul anywhere where's the metal/brick juncture has any gaps.

Thanks for your thoughts.