Reducing size of knee wall

[Walshy252]

1930s semi, our smallest bedroom was split into a small wardrobe and has a vaulted ceiling on one side, with a stud wall about 1.4m high. No insulation so just lathe and plaster between the room and the roof tiles, and due to the position of the stud wall, a tonne of wasted space in the eaves.

I've opened up the cupboard and want to remove the existing stud wall and rebuild it further back into the eaves to increase the space available in the room. Reducing the height of the wall from 1.4m to about 0.7m and leaving the purlin where it is. The original stud wall is nailed to a 4x1 that spans the rafters and sits on the floor joists below which span the garage. Purlin span is 4.4m. As you can see in the attached photo I've built the new wall ready, and engaged a structural engineer who originally said it would be fine and is now saying do not recommend due to potential additional weight on the purlin and the purlin doesn't pass modern check calcs.

You can get a sense of where I am up to in the attached photo. I don't regret knocking it all out as there is a big benefit from adding insulation, but at a loss on what to do next. Worst case scenario I can rebuild the wall in its original place and incorporate some built in storage, but would like to gain some extra space if I can.

Any thoughts or ideas?

 

[freddiemercurystwin]

Is this a loft conversion? Ordinarily you would build a structural stud wall directly beneath the purlin because as your SE says, the purlins are generally inadequate without it.

 

[Scally-Ho]

My 1st thoughts are what is the room below. Could the room below benefit from a wardrobe and could that wardrobe conceal a few supports?

 

[Walshy252]

Is this a loft conversion? Ordinarily you would build a structural stud wall directly beneath the purlin because as your SE says, the purlins are generally inadequate without it.

Its not a loft conversion but came here as its similar type of work and space being adapted. Its a first floor bedroom and the ceiling follows the roofline down to an outer wall. The vertical supports you see at the front of the image are original. They are fixed to the rafters above and below the purlin but not providing support to the purlin directly. They are also not directly supported below, whatever load they are taking is spread over the floor joists

 

[freddiemercurystwin]

Can you not just build a new stud wall here, in line with the existing one on the left, depending upon what's underneath (SE permitting).

 

[Walshy252]

Can you not just build a new stud wall here, in line with the existing one on the left, depending upon what's underneath (SE permitting).

View attachment 389038

This was my follow up question to the SE and waiting for a response. Gives me a little less space in the room but will attempt to build some cupboards/drawers into it if I can