Opening up chimney breast- full width lintel

[Locoblade]

Hi All

Our living room has an unused fireplace I want to form the basis of built in units to one side and a media wall for the TV on the existing chimney breast as it's the ideal place in the room for it, but we'd also like either a wide decorative fireplace or openings underneath the TV across the full width of the chimney breast where the old fireplace is. That leaves me with a problem to solve with the existing fireplace opening as the lintel is currently only about 2/3 of the width of the stack so doesn't give me the opening width I need.

We don't have the budget or dust tolerance to remove the chimney stack entirely across 2 floors and it's too big for gallows brackets so what I'd like to do is replace the existing lintel with a full width lintel/steel, ideally with front plate to support the front brick face to create about 10-15cm of overhang across the chimney stack. This would give me enough undercut to put the fireplace / alcoves underneath and build out the front face a little with studwork without the whole thing taking up too much extra room space.

Is what I'm proposing do-able (images below) or is there a better, more recognised way to achieve this? Whatever we do I'm guess it would need structural engineer calculations and BC notice would it?

cheers

 

[George_engineer]

Hmmm... not usual and not sure I like it very much --- lintels with projecting plates usually sit fully onto a wall (or outerleaf for a cavity). This resolves the torsion in the lintel created from the plate. I think if I was doing this I'd make it into a steel U-frame built into the chimney which would prevent any rotation in the main lintel.

But anything is possible - contact a local engineer.

 

[Locoblade]

Thanks George, my thinking was it wasn't dissimilar to a steel beam and plate across a door/window opening with the plate supporting the outer leaf but having spoken to a structural engineer he said doing it like this would need support under each end of the plate to be stable and counter the torsion it would introduce. Back to the drawing board