"Cantilever/slab" footings?

[barcyn]

Just finished a long, drawn-out tussle with neighbours re Party Wall Act regarding single storey extension that we want to build as close as possible to a "Party Fence Wall". The upshot is that I need to put the cavity wall on the edge of the footing rather than in the centre and was told by party wall surveyor that I could use "Cantilever slab". After all the party wall survey costs the budget's a bit stretched so I'd like to work the spec out myself to submit to BCO for approval.
I'm a mech engineer, so pretty confident about doing drawing/calcs, but can't find tech spec/guidance anywhere on the interweb, even in Part 'A' Building Regs.

Any ideas where I can get relevant info?

Thanks in advance.

 

[freddiemercurystwin]

Eccentric foundation is the term you are looking for, other's may be able to advise as to how to design.

 

[RonnyRaygun]

6.3.6 Position of walls on foundations
In general, walls should be positioned so that the vertical centre line of the wall
aligns with the vertical centre line of the foundation [see a) or b) in Figure 24].
Where the external face of a wall is at or near the edge of the foundation, for
example where the foundation position is determined by a boundary to an
adjacent property, [see Figure 24c)] it is sufficient to ensure that the vertical
centre line of the wall is within the middle third of the foundation width as
recommended in 6.3.2.

BS8103-1 2011 - Pg 34

• RonnyRaygun
• 3 Sep 2015

 

[barcyn]

Thanks a bunch Ronny - going to save me a load of work (money!). Looked at buying the actual BS but at >£200 I'd be throwing a lot of my savings away.

Thanks again.

 

[tony1851]

If it's just single-storey, why not do a raft with thickened edge beam?