length of wall and windpost

[stephanh]

I have just become aware of windposts and have been trying to understand, so have I got this right?
I have completed drawings for extension to bungalow, imagine a new box attached to existing. The gable end walls are 6700mm long, one of which has a chimney half way along. One of the walls between the gable walls is 9900 long and has 2 french casement openings each 1800 wide. The other wall of the box connects to existing structure and has maximum length of wall of 4500. Walls are 350 wide cavity walls, external leaf 7.3 conc blocks, inner leaf 3.6 aerated blocks plus insulation.
Ceiling height to be 2700mm.
As I understand it, I need to have this 9900 wall buttressed, or failing that incorporate a windpost.
I had intended to have a studwork wall midway between the 2 french casements, each with 500mm reveals to stud wall.
This stud wall was to be bolted to the conc slab and to have 18mm OSB fixed to either side.
Have I got this right, or does this specification not meet the buttressing demand and I must have the posts???

 

[^woody^]

We could probably imagine better with a floor plan.

 

[stephanh]

Well I eventually managed to attach something to look at - it took time, I'm old, I have white hair ...... what can I say??
Anyway ....... I suppose I could reduce dims by a metre to take it out of the requirement, but I would rather not

 

[cdbe]

Obviously a domestic external house wall does not need any buttressing along it's length. But if it did, a suitably designed stud wall in the location detailed, or even a masonry wall in its place, would surely suffice?

 

[^woody^]

The length would be measured internally.

This single-story wall should not require buttressing, the roof is restraining it isn't it?

 

[freddiemercurystwin]

Internally? To the face of the wall, finishes or skirting?

 

[^woody^]

Internally? To the face of the wall, finishes or skirting?

Hmmm, I'm not in a position to state that "its clear", but my spidy sense tells me that plaster and skirtings are not structural. HTH.