How to fix cracking chimney/flue? (lots of pics)

[p4ult]

I think the garage was built at the same time if not slightly after the house (50's). There has been a small brick built conservatory/lean-to built about 15-20 years ago.

I have a friend who is not a bricklayer by trade but is handy when it comes to building walls etc. Would I need a professional bricklayer or could we do it? How would we support the stack while doing this? timber and a couple of props?

Thanks
Paul

 

[Shytalkz]

Not dropped, and not the whole stack, but if the load is not being transmitted to the main wall via bonding, then wouldn't it cause a shear crack in the brick at that point?

Yes the soot door arrangement will contribute, but the way that crack has formed where it has through the two corbels, would seem to me to be more load related than thermal

I reckon that part of it is thermal; however, there's a tad of rotation at the bottom, due to the corbel failing, but if the stack as a whole was going, you'd get cracking where the stack ties into the main wall, as the stack bulged out away from it. It's clearly moved a bit in the past, as indicated by the past repointing exercise/s.

Personally, I think that you only need to temporarily prop above the level of the soot door, get rid of that if you don't need it, rebrick the lower portion up to the needle level and introduce an addtional course of corbelling a) to cut down the overhang per course, b) to get the coursing to come right, above the top corbel and c) to allow the load to be taken by the entire length of the corbel, not just the two half bricks at the side of the soot door. Slate pack between new and old work, to get a tight fit and stop future relaxation above this level.

 

[p4ult]

Thanks for your help guys

 

[AtoZ]

Not dropped, and not the whole stack, but if the load is not being transmitted to the main wall via bonding, then wouldn't it cause a shear crack in the brick at that point?

Yes the soot door arrangement will contribute, but the way that crack has formed where it has through the two corbels, would seem to me to be more load related than thermal

I reckon that part of it is thermal; however, there's a tad of rotation at the bottom, due to the corbel failing, but if the stack as a whole was going, you'd get cracking where the stack ties into the main wall, as the stack bulged out away from it. It's clearly moved a bit in the past, as indicated by the past repointing exercise/s.

Personally, I think that you only need to temporarily prop above the level of the soot door, get rid of that if you don't need it, rebrick the lower portion up to the needle level and introduce an addtional course of corbelling a) to cut down the overhang per course, b) to get the coursing to come right, above the top corbel and c) to allow the load to be taken by the entire length of the corbel, not just the two half bricks at the side of the soot door. Slate pack between new and old work, to get a tight fit and stop future relaxation above this level.

i agree
just repair it and it will take a couple of hours as opposed building up from the bottom which will take a lot of work for a couple of cracked bricks.
even if some of the tie bricks have been left out the stack will not fall.
the bottom of the corbels are not cracked, so its a simple repair.

worse comes to worst and your repair cracks, build from the bottom at that time.
why make work