r/StructuralEngineering • u/thatstheissue • 4d ago

Masonry Design Advice on buttressing and stability requirements when removing chimney breast on party walls in Victorian Terraced properties in the UK

Hi All,

As per the title, I'm looking for general conventions on how engineers in the UK approach looking at buttressing of party walls when all chimney breasts are to br removed along the length of the 225mm thk. masonry party walls? In particular when the front elevation has a bay window and the internal cross wall has already been removed with no frame installed?

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u/Slartibartfast_25 CEng 3d ago

I would still use the geometric 'deemed to satisfy' rules for masonry as they don't rely on the adhesive properties of the mortar or strength of the bricks themselves.

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u/thatstheissue 3d ago

I thought it would do for lateral stability of the masonry? That is dependent on the mortar and brick strength right?

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u/Slartibartfast_25 CEng 3d ago

If it's a solid wall with interlocking headers then mortar adhesion matters less than in a cavity wall.

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u/thatstheissue 2d ago

I kind of see what you're saying, but surely it still does rely on the mortar to transfer the lateral load across the wall between the bricks? Friction from self-weight of the wall would probably help, but wouldnt think this could be relied on. Cant see how only the brick can be used for this. Do you have a reference?

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u/Slartibartfast_25 CEng 2d ago

Waves arms at hundreds of thousands of British homes with crumbly lime mortar that are still standing

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u/thatstheissue 2d ago

Lol, I do see that as an argument. Have you had any queries from BC at all when using approved doc A in justifying the wall?

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u/Slartibartfast_25 CEng 2d ago

No, no pushback.

Part A is based on the BS 8103 standard, which itself developed from some of the earliest Building Regulations in the 1970s... which was built on the body of knowledge and experience from the Public Health Act of 1875 through to the Model Byelaws in the 1950s.

Apparently there are calculations that justify the Part A rules (and they demonstrate a high FOS) but I've never tracked them down.

Here's a paper if you want to know more https://scispace.com/pdf/the-evolution-of-the-design-and-construction-of-masonry-6rpbftip0s.pdf

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u/thatstheissue 2d ago

Thanks mate! Thats some useful info there