Strange metal beam in party wall

[Guynextdoor]

Hi All,
I live in a row of Victorian terraced houses and I've posted pics of my existing single storey kitchen extension and the two storey party wall that my neighbour and I share.
This party wall and the neighbours two storey extension (left of the pics) was built in the 1980s and I've lived here for nearly 20 years with no issue or deteriation in the party wall.
I'm considering my options for a new single storey kitchen extension or even a two storey extension as next door have, but.......
What do you make of the steel beam set into the party wall above my kitchen roof ?
Is it normal practice? Why is it there? Should it be covered? Should I steer clear and build my own internal wall?
Would appreciate thoughts on the beam please.
Thanks

 

[23vc]

I notice that everything above it’s stretcher bond but solid wall below - steel could be carrying the inner cavity leaf?

 

[Guynextdoor]

Thanks, that's a good spot ! I hadn't noticed that.
So there is probably an original solid party wall at ground floor level, possibly sloping as per my kitchen roof and they built it up to be level, added the lintel then built a cavity wall on top.
Would a cavity wall be thicker overall then a solid victorian wall ?
What do you think of the steel being exposed like that ?

 

[23vc]

Yeah, the cavity wall would be thicker. Although not necessarily by much
Also note the bolts, which suggest it’s bolted to another steel (which might be carrying the inner skin).
No idea why it’s exposed/it shouldn’t be

 

[DAZB]

There appears to be a lack of mortar just below the steel for the top course of bricks which could suggest it was an opening at some point and it has been bricked back up maybe ?

 

[Guynextdoor]

I think that could be a possibility if it were the front of the house. There are houses around here with steels across the front if they are former small shops that have been turned into houses. But this is between mine and my neighbours.
I guess there was an existing low solid party wall and they built on top of it to avoid disturbing my kitchen back in the 80s.
It's a shame the party wall has been build in a weird way as I'm less inclined to make use of it for a first floor extension. I've just never seen this done before, a cavity wall built on top of a solid wall......?

 

[23vc]

Yeah it’s a thing, when the existing solid wall is deemed ok to support a cavity wall above. but wouldn’t normally involve the whole steel being exposed like that. Can be done with a steel with a welded flat plate/lip, or a single steel only on the inner skin

 

[Guynextdoor]

Hello,
I've been thinking a bit more about our party wall and the observations that have been posted in this thread and have another question please.

The cavity wall above the steel was build in the 80s, are they supposed to have weep holes at the bottom (so on top of the steel) ? Looks like there are none although there appears to be a gap below the steel and top row of bricks of the solid wall beneath....

If I were to level my kitchen roof for a single story extension to just above the steel, is there a risk that it would cause damp either on my side or my neighbours if water is supposed to escape from the bottom of the cavity ?

Thanks.

 

[Harry Bloomfield]

Also note the bolts, which suggest it’s bolted to another steel (which might be carrying the inner skin).

U channel steels, bolted back to back?