Partial Chimney Demolition 1

[RAGE69]

Need to demolish a section of an existing masonry brickwork chimney - section between ceiling and ground floor needs to go while maintaining the section from ceiling level and above. Section of chimney to be retained is 470mm X 470mm and about 3.0m high.

The builder wants to just use steel beams to support the chimney.

Should there be a steel framed collar fixed to the chimney (say just below roof level) and braced back to these steel beams?

 

[BAretired]

You need to provide more detail than that if you want a useful response. A plan view and section would be a good start.

BA

 

[dhengr]

RAGE69:
BA’s right, you need to provide much more info. if you want meaningful discussion and answers. Photos showing the existing conditions and a good understanding of the structural conditions around the chimney are essential, with some well proportioned sketches of same. Otherwise, you are sorta saying…, ‘you guys guess at anything and tell me what to do, it might fit my needs, and waste your time, not mine on my project, because I won’t spend mine (to lazy?) to explain fully.’

Ask a good mason how he would do it, what he can do. Question him on what he’s going to do as he explains it. Then explain that you’ll work with him and coordinate the structural aspects of the demolition and supporting of the remaining chimney. Likely, he’ll say this is how we can temporarily support it above our work elev. Is this o.k. with you and your known support points? Then, as soon as he’s removed a few courses of brick/block, or a few discrete blocks, slip in the new support system. Then finish the demo. Consider a .375” by 18” sq. stl. pl. and beams under it, to whatever. Put a cleanout door 6” (2-3 brick courses) above the stl. pl. and puddle 3” of conc. on top of the stl. pl., inside the chimney, fire and heat stop.

 

[Ron247]

Seems like a lot of work to salvage a small chimney. Can you not tear the whole thing down and build the upper part back new?

 

[BAretired]

I tend to agree with Ron247. It isn't worth saving.

BA

 

[JStephen]

What comes to mind is to drill holes through the assembly, insert rods or pipe, put mortar around those, add supports, and at some point start chipping away at what is below. Recognize a distinct possibility of the whole thing coming down anyway.

It would be funny to watch the next owner/occupant try to find the fireplace that goes with that chimney.

https://www.youtube.com/watch?v=HF1pHzGkSC4

 

[msquared48]

If the flue will not be functional, then why save it?

It just adds seismic risk and is a liability to the structure and any occupants.

Are you merely trying to avoid redoing the roof?

You know, considering potential deflection issues with the lower portion removed, you are very likely to develop leaks ay the periphery of the flue at the roof.

Just sayin’...

Mike McCann, PE, SE (WA, HI)