In need of new chimney flaunchings

[Venomgrass]

Hi,
My chimney flaunchings were shot at!
I've removed all 4 pots, all the flaunchings and 2 layers of bricks down to the concrete band you can see in the below image. How should I go about rebuilding?

A roofer recommended using a sheet of lead and creating a tray which sound good but because my chimney is 2.27m x 0.85m the lead at code 4 will cost £200!!!!

Any other good advise please? It' a long way up here 16m high and I can't get up here without the scaffold I currently have on the house so don't want to be redoing this.


Thanks.

 

[Doggit]

Can I assume the tray is to support the corbaled bricks as you build outwards and upwards.

 

[Venomgrass]

literally a layer of lead with 4 holes cut for the pots so if any water gets down the pots inside or outside should drip onto the tray and out of the side. Id put fresh mortar over the lead and leave small holes for any water to drain out of.

Any other ways of weatherproofing this once and for all please?

 

[Doggit]

I think this is being tackled from the wrong direction. Any water going down the pots will go straight down, and any that doesn't will just hit the bricks at the top of the chimney. If the chimney's are still in use, then a chimney cowel would solve that better, and if they're not in use, then a cap would stop any rain going in. If you put a lead tray in, and then drip holes, it's need to be set very carfuly so that the water doesn't pool in the wrong place, and any dirt could block the drain holes.

If you've after stopping water going down into the roof space, then you'd do a silicone injection in to the lowest layer of mortar before the roof line, and in to the perps as it steps down.

 

[datarebal]

Firstly, A tray should be lower down the stack not near the top. You have four large pots which offer a lot of wind resistance. in this case a lead tray will create a weakness.
Fit cowls, or take the stack down to the correct level fit a tray and rebuild

 

[Venomgrass]

Firstly, A tray should be lower down the stack not near the top. You have four large pots which offer a lot of wind resistance. in this case a lead tray will create a weakness.
Fit cowls, or take the stack down to the correct level fit a tray and rebuild

Thanks you everyone for the responses. Only one of these chimneys is to be used... Can I literally fully close the other 3 or do you still need air vents?

As for the lead if I was not to use this and just cut a board of hardie backer cement board mortar it up on the stack with one hole cut for the usable pot. Position the pots (3 for display only) and then mortar a tapered flaunching?

Would this be ok?
Thanks again

 

[datarebal]

Vent them
The lead was to limit damp in the stack. (if I understood correctly.
It isn't to support your muck.
Hardie backer .. Thinking of tiling it?

If you are just doing the chimney head then build it back as you found it.

 

[Alastairreid]

This guy was a poster on here for years, knows his stuff.

 

[Doggit]

Yes he does, but he's installing a tray to act as a dpc. You can see from the OP picture, that he's (erroneously) working on the top of the stack, but would need the tray at the roof line, but it would be far easier to do a silicone injection in the mortar line. He needs to cap the 3 unused stacks, but the caps should have an airgap just under them, and the chimney breasts should have a vent in the rooms just above the skirting boards. If the chimneys haven't been swept, then they should be (even from the top if necessary, and he needs to drop the hardibacker idea as well.

 

[Alastairreid]

Unused stacks such as this act as sponges with the absence of heat going through them to dry them out.
Unless the stack has some architectural or aesthetic significance i would consider dropping it and rebuild a single stack to service the one in use.

If the stack is on a gable the vents can be inserted externally both low and high level.

What purpose would a silicone injection serve?

 

[Doggit]

Unused stacks such as this act as sponges with the absence of heat going through them to dry them out

Hence the need to vent them top and bottom to stop that.

If the stack is on a gable the vents can be inserted externally both low and high level

Interesting suggestion, I haven't come across doing it that way before. Thanks for that.

What purpose would a silicone injection serve

If the stack need taking down and rebuilding, then you'd add a slate dpc, but if the stacks okay, then a silicone injected dpc into the mortar line and the perps around the roof line, is a much more straightforward way to do it