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

[p4ult]

As above realy guys, is it in danger of falling down? Should I put a prop or timber support under there?

It looks like it has been repaired before? How should I go about fixing it?

Thanks
Paul

 

[noseall]

build it from the ground up.

has that corbelling suffered some kind of impact?

the corbelling plus the soot door make for a weak spot.

 

[Richard C]

build it from the ground up.

has that corbelling suffered some kind of impact?

the corbelling plus the soot door make for a weak spot.

Seems the obvious solution. I can’t imagine why they built it like that in the first place; unless it’s to provide a minimum 1m clearance @ 2m height to that boundary wal! Is that your only means of access or do you have another on the other side of the property?

 

[roughcaster]

Crazy There's a whole lot of weight up there.

Roughcaster.

 

[^woody^]

Ordinarily, I say this stack is tied in and so is not going anywhere. But looking at the bond, it looks like it is not tied in in the areas in the photos, and so its questionable whether it is tied in sufficiently - if at all.

That is what could lead to the corbel cracking as it's taking more weight than it should.

The answer is to tie it in properly at least for the bottom metre or so.

A new foundation and new section from the ground is then other option, but IMO, its overkill and you then lose the width of the walkway

 

[Richard C]

Ordinarily, I say this stack is tied in and so is not going anywhere. But looking at the bond, it looks like it is not tied in in the areas in the photos, and so its questionable whether it is tied in sufficiently - if at all.

That was my initial thought as well; hopefully Mr Bricky didn’t just us ½ bricks instead of bonding & then ram some mortar in there! I’m a little concerned about building up from the ground as at the back of my mind, I’ve got a nagging feeling that if it’s the only access, it has to be a clear 1m; why I asked if there is another access at the other side!

 

[JohnD]

the fat mortar joints look like they have been repaired before.

I suppose you could bolt some steelwork gallows to the wall as the corbelling doesn't seem to be working

If it was properly tied to the wall it should be unable to move like that.

 

[Richard C]

Snap

 

[Shytalkz]

Sorry, not convinced that the stack as a whole has dropped: there is some disturbance at the lower level, ostensibly due to the soot door breaking the integrity of the stack structure, and the cráp bonding arrangement directly above the top corbel (check the header three courses below the soot door, it barely bears onto the corbel below) but there is nothing above the soot door level.

I bet the majority of the cracking is thermal from use of the flue, with a bit of rotation of the corbelling. If you knocked out the bottom section including the soot door, the rest of the stack would hang there quite happily.

Not a major problem and no evidence of incipient collapse.

 

[^woody^]

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

 

[p4ult]

Hi guys,

Thanks for your replies.

I am still a little confused as your views seem mixed.

Yes that is the only access to the rear of the property. But I am not worried about losing access if I build up, the photos are a little deceptive, the walk way gets bigger before the stack as the garage ends before the stack. (see photos below)

Thanks
Paul

 

[Richard C]

Hi guys,

Thanks for your replies.

I am still a little confused as your views seem mixed.

Yes that is the only access to the rear of the property. But I am not worried about losing access if I build up, the photos are a little deceptive, the walk way gets bigger before the stack as the garage ends before the stack. (see photos below)

Thanks
Paul

Well that makes things clearer & my concerns about falling foul of minimum access won’t be a problem if you decide to build down.

The debate going on at the moment is whether or not the stack has been correctly built; if you look at the side of the stack where you can see the 2 half bricks, the one nearest the main wall should, in fact, be a whole brick (going into the wall) so bonding every other course into the wall, this would make the stack self supporting over it’s full height. What’s not clear from the photos is if it is bonded or it’s been built with just a half brick butted up against the outside wall; this would mean the stack is, effectively, just stuck on the outside of the house!

Out of curiosity, what’s that square bit that’s been bricked up below & just to the left?

 

[p4ult]

Out of curiosity, what’s that square bit that’s been bricked up below & just to the left?

Hi Richard, thanks for your reply.
I dont know what that bricked up hole is. I have only had the house 6 months. The kitchen is the other side of the wall, I have a feeling thats where the kitchen sink used to be, maybe the drain pipes used to come through to the drain on the right if the pic? Just a guess tho?

Back to the stack, is there anything I can do to help you guys? more pics etc?

Say we do decide it is not bonded in properly, if I bulid up will that be the easiest way to solve the problem? I take it foundations would have to be dug?

Thanks
Paul

 

[^woody^]

I'd still say just rebuild the botom metre or so, and unless you use it, remove the soot hatch and block it up

 

[Richard C]

I'd still say just rebuild the botom metre or so, and unless you use it, remove the soot hatch and block it up

Probably the best immediate option & see how it goes; it will also give the opportunity to see if the stack is in fact bonded in to the main wall.

Is that garage original or built at a later date? Has there been any building works done out the back? A long shot but the other thing that occurs to me is that it's entirely possible that someone’s clouted the bottom of it with a mini digger or JCB & then botched the repair!