Steel Box Frame to support outside wall - Extension

[Django x2]

Sup,

We are having a single storey extension out the back (mid terraced house). I had heard of these new steel box frames rather than a supporting steel frame rsj (which would be required to sit on brick). Instead, these steel frames are literally like a picture frame, they sit along the bottom of the wall, up the sides and then support the roof too.

Make sense?

If we have a traditional RSJ style beam, it will mean the internal walls will have a small pillar style kink in them, which we'd like to avoid if possible.

ie, what we don't want:
where it has to sit on the existing return of the rear wall.

and what we do kind of want:


Anyone done something kind of similar and where the costs drastically different?

 

[Derek W]

weigh up the difference between a few engineer bricks / concrete pad stones compared to two extra steel supports (columns or PFC channel depending on loading)with potentially new foundations underneath. If you want something with a cranked steel beam as you've linked above then that will increase the cost more.

Re read what you're planning. You're mid terrace, how wide are you planning to have the extension or how close are you building to your neighbours boundary?