Wall cracking next to RSJ

[ABF1]

Hi all,

I’m just after some advice as to whether you think this is subsidence or something else
I’ve got a 1950s semi detached thats had no building work done. So original brickwork.

I’ve noticed hairline crack about 1mm in the plaster downstairs near RSJ that supports the upstairs bedroom floor joist a wall. In the upstairs bedroom about the RSJ the plaster is also cracked. I’ve cutt the plaster out with a blade best I can to get a better look and noticed the breeze block behind is cracked maybe 5mm.

Downstairs is open plan with an RSJ that supports the joist above and bedroom wall which is slightly offset.

The ground floor is red brick up to about waist height and then breeze blocks all the way up to the first floor ceiling, then goes back to red bricks into the loft? I think anyway as that’s the brickwork I can see with my cut outs,

I’ve took up the floor boards to inspect the RSJ and noticed that 1-2mm thick bits of rust have flaked/fallen off the RSJ all long it and where it goes into the party wall. It still feels solid after 70 years but abit concerned how 1-2mm of surface rust flaked off can flake off an internal steel.

Where the RSJ sits into the party wall, either side of the RSJ is blocked off with black ash lime mortar and bits of red bricks which I think are bedded to the breeze block wall. This breeze blocks appears to have split all the way down.

I can’t see cracking to the plaster anywhere else or even to the external brickwork. There also isn’t any cracks in the red brickwork in the loft.

Any ideas on where to look next or what you think the issue could be would be greatly appreciated. I will get a structural engineer if needed. I’m just trying to get my head around what could possibly be causing this and if I should be concerned.

I’ve attached some pictures and poor drawings to try help explain.


Cheers

 

[ABF1]

More pictures

 

[ABF1]

Just to add some more information. I’ve taken back the plaster some more and it appears the old breeze block has cracked a little but stopped at the engineering bricks further down.

Do you think this is just normal settlement/termnal expansion. If so what do you recommend to fill the cracks?

 

[^woody^]

Your pictures are too close. Take some from the other side of the room

 

[ABF1]

Hi Woody,

I've taken some pictures from across the room. Please excuse the foil tape downstairs and UPVC board upstairs. As it's a party which is vented there's a slight draught coming through so sealed them off temporary.

The downstairs wall is cracked slightly from the side of the RSJ down to the engineering bricks. The cracked bricks are old clinker blocks?

The upstairs party wall is cracked where it meets the bedroom which is slightly offset from the RSJ and built directly onto the floor boards and joists, latter resting on RSJ.

The block above the RSJ doesn't sit on it but has an cut out. What i have noticed is the sparky from the 1990s (last council house rewire) has smashed a hole in the brick and blown the back off it to fed the cables through.

I'm unsure if there's actually two separate issues or one that's caused both and if I need be concerned or not.

Just to note the house had CWI (Fleece type) installed in 2008 by the previous owner. Obviously it wasn't installed in the party wall. No idea if that could affect thermal movement?