Diagonal growing crack

[warey4life]

Hello,

I've got a crack problem.
On my staircase I have a crack which starts at the ceiling from an RSJ and runs diagonally down the wall. It's grown about a meter in the last few years but I've noticed recently that it seems to be getting wider. It's about 1mm wide.
Just wondering what to do about it really. Get a surveyor or a structural engineer to have a look? Or maybe a builder?
I've attach photos but not sure they are clear enough.

 

[ree]

OP,
Typically, 1mm-2mm cracks are often not significant.
Is the RSJ supporting a loft conversion floor?
There's shadow near the crack - is it a damp patch?
Is that an external wall? Is it rendered? Any external mirror cracks?
Is it a solid wall or a cavity wall?

 

[warey4life]

OP,
Typically, 1mm-2mm cracks are often not significant.
Is the RSJ supporting a loft conversion floor?
There's shadow near the crack - is it a damp patch?
Is that an external wall? Is it rendered? Any external mirror cracks?
Is it a solid wall or a cavity wall?

RSJ is supporting a loft convertion which was done in the 70s. Also new staircase was put it, photo attached.
There's no damp, just a rubbish photo and poor lighting.
It's an internal wall between our house and next door.
It's a solid wall, how thick and whether its just bricks I'm not sure.

Our house used to be a 6 bed semi, but in the 70s it was split into two, so we are now a 3 bed semi.

I've got floor plans for next door which hasn't been converted and is still 6 bed, trying to find our floor plan, I'll upload when I find them.

 

[warey4life]

Floor plan of my house.

 

[warey4life]

Floor plan of next doors house which is on the left and still a 6 bedroom house.

 

[ree]

OP,
Thanks for the last pic & diagrams.
What we do know is that substantial building/structural work has taken place in the original semi - we also know the party wall supporting one end of the RSJ is probably 9" - & hopefully the lintel is supported by a padstone?
We dont know if there are any cracks on the neighbour's side of the party wall?

All the building work took place a long time ago while the crack appeared years later.
So for now why not simply keep an eye on what might be, due to heating & cooling, a typical thermal movement crack with a bit of added lintel/load pressure?

 

[warey4life]

Thanks ree. Not sure if the RSJ is supported by a padstone, I can only assume.
I'll pop round to next door at some point and enquire whether they have a crack on the other side.

We would like to strip all the woodchip off and re-plaster, but don't want to go ahead if it's just going to crack again.