Narrow pillars, cavity wall

[Notabrickie]

Please can someone help with my question? A garden building will have one-block-wide, 2m high narrow pillars between tall windows, supporting a flat roof. The wall is insulated brick/block cavity. What is the correct way to build the pillars, for adequate strength, without joining them at the window reveals? Will two leaves with metal ties be robust enough, with pillars that narrow? They will be connected with lintels at the top, which will in turn support another three courses of brick as a parapet.

[Edit] Thinking about it the window sill height is 500 so there's only 1500 height, maybe will be OK and worrying too much

 

[^woody^]

Cavity walls dont need piers, they are strong enough

 

[Notabrickie]

Ta. Even when they are only one block wide with a window each side? Great

 

[^woody^]

The wall is as thick as the two leafs plus cavity.

 

[tony1851]

Isn't there a minimum width of masonry between two openings, as per diagram 14 on page 27 of Approved Doc. A?

 

[Notabrickie]

P.31 in the online version I see. As I read it, our windows are 750 wide, so P2 (a typical bit of wall between them) should be greater than or equal to (750+750)/5. (5 is from Table 8. 1500/5 is 300, which is smaller than the width of one block. So we're OK assuming all other conditions in the diagram and the notes are met

 

[^woody^]

You would span a single lintel across the openings and this in turn stabilises the pier