Removing Chimney Breast and Replacing with Built in Windpost into 215mm party wall.

[liam1369]

Good Morning All,

Has anyone dealt with the installation of an SHS windpost built into an existing 215mm thick party wall.

Building control want the buttressing effect offered by the chimney breast to be replaced as the length of the flanking wall is circa 9.0m.

However, understandably, the client does not want a box out to allow a face fixed SHS windpost as it looks like a boxed out column and sticks out into the room.

I am thinking the following proposal, however, it will inevitably split the wall panels and there is a portion of the wall that only has 100mm brickwork behind. In addition, I am not too sure if it is the same story on the neighbours side.

Any advice from people who have dealt with this scenario would be appreciated. Of course, if there is a simpler way of doing this, I will of course be greatful for any guidance.

Attached proposal and scheme below.

 

[liam1369]

Wall Panel Analysis

 

[liam1369]

 

[liam1369]

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[phamENG]

Yes, removing the chimney will change the wall behaves locally, but walls like this typically span vertically between floors. I never consider the presence of the chimney as a stiffening factor unless it's absolutely necessary. Have you attempted to demonstrate to them that it doesn't really matter? If they won't buy it, can you convince yourself of that and then provide something that satisfies them and at least doesn't weaken the wall?

 

[liam1369]

As the flanking wall is 9.0m long the axial load based on ratios is reducing a bit.

Building control told me that the removal of the chimney breast reduces the effective thickness, in a similar way piers can increase the effective thickness of a wall.

I get their point but I am worried about installing the windpost within the profile of the wall. It is supporting the joists for the neighbours property as well.

 

[phamENG]

I'm the US, so I think in imperial units. 215mm is about 8.5 inches thick. 5200mm total height...that means your walls spanning about 8 feet. There are unreinforced masonry walls 8" thick all over the world with no buttresses.

So putting aside what building control is telling you...what have you done to determine if the wall can work without this wind post?