Large RSJ padstones flush with wall

[EvilDonut]

A planned kitchen extension relies on removing my existing rear wall. The RSJ would span 5500mm and support first floor (possibly joists, not checked yet) and gable-end roof wall, so it's going to be a bit chunky!
Is there any way I can make at least one side of the padstones/nib flush with my side wall?
Not sure how wide the wall is. It's a 70s house and I'm guessing 300mm: 100mm block, 100mm cavity, 100mm face brick.
Would I need a steel pillar or can I achieve this with masonry alone?

And before you say it yes I will get a structural engineer involved eventually - this is just for my initial CAD planning phase

How much of the original walls' corners should I plan to leave in place?

 

[^woody^]

You don't need any nibs, and the 100mm bearing of the existing walls is always enough.

 

[EvilDonut]

Ahh OK that's great then. I've seen plans where the SE has recommended a 150mm support from the padstones and that had me a bit worried.

If they did recommend 140-150mm, could I build those into the cavity (which I'm hoping is 100mm) rather than project into the habitable room?

 

[^woody^]

could I build those into the cavity

No, a padstone needs a wall under all of it.

 

[EvilDonut]

Yep sorry I meant both the padstone and the nib below it being built up to 50mm in the cavity, should 150mm be necessary (5.5m does sound like quite a wide span after all)

 

[tony1851]

This is a nib-free zone.

 

[Scubatt]

Hi Evildonut how did you overcome your problem? ... I have a similar one. I'm trying to get 5.2m opening at a corner and anticipating a roof in the room in future I'm looking at a 203x203x46/52kg UC to span the gap. At one end I need little or no nib to accommodate the clear opening for the wall of units. I can get away with a small nib as the room will allow for it but anything too big and we will end up wasting space! I have found that a 203x102x 23kg UB turned vertical will support the load but am having probs with the bearing at the base. I'm looking at using a 250x300x10 base plate offset to one end of UB which will bear onto 2no 440x215x100 on both sides of the cavity. Calculation wise the bearing is fine however I'm a bit worried about it being eccentric to one end. Any thoughts?

 

[EvilDonut]

In the end I used an architect and SE, who proposed a moment frame design. Our span is 8.8m and one entire corner of the house will be roughly in the middle.

A moment frame, a.k.a. Goal post frame, uses vertical steel columns securely bolted to the horizontal member to provide lateral stability. And no nibs!

You need large pads for the foundations though, the recommended size is 1m x 1m x 1m though for us we need to slightly elongate them as one is near a boundary.

 

[Scubatt]

Crikey! That's a lot, although it sounds huge. I don't suppose you have a picture to substantiate? I've only moved mine out by 400mm and it was ok on a brick pier according to building regs! (Passed) but I want this clear wall now as our kitchen doesn't work as well as we want....