Widen Fireplace - Support Flue (4 Inch Block)

[RDWRER]

My fireplace and chimney is built from 4 inch blocks. The gather to support the flue is just two angled blocks resting on the first layer of block below the lintel as in the diagram. I haven't figured out what holds these up yet. It could be a pre-cast gather but it looks like block.

I want to open up for a stove so plan to go in with a new lintel above and cut the blocks to widen it. The question is how to support the flue. Has anyone tackled a similar type of chimney design? Perhaps a couple of internal steel lintels (like Catnic CN102) might work best here?

 

[ree]

RDWRER,
The proposed stove will need a sound flue that would pass a smoke test. So I'm cautious about giving advice before seeing more of whats existing.
Why not post a stand back pic of the front of the chimney breast, and a pic of the fireplace?

 

[RDWRER]

Thanks, I should have mentioned the flue will be lined with a flexi kit.

I'll get some pictures shortly.

Part of me suspects there is perhaps blockwork behind those angled gathers supporting the flue, meaning the construction is something like this:

 

[ree]

You will need to make sure that the stove Mfr's flexi diameter required for your stove - usually 4" or 5" - will fit through the existing masonry flue.
Your "gather" arrangement was probably the simplest & quickest solution for the brickie who built the construction?
You could cautiously open the chimney breast up for a look above the "angled gathers"?
I'm not a brickie but hopefully one will come along on here to help you better?

 

[stuart45]

I'm a brickie, but I've never seen that method used before. The precast gathers are in one piece, or when brickwork is used, the bricks are cut and corbelled.
Looks like there were gaps for smoke to enter besides the flue.

 

[RDWRER]

It's a 1950s construction and does seem a bit odd

 

[stuart45]

What's the diameter of the existing flue?

 

[RDWRER]

Existing flue is 8 inches diameter, blocks are all 440x215x100