Footings, or sleeper walls?

[larry]

Hello all,

 

I've been pulling up my floorboards and joists to relay with insulation in between. 

The picture below shows a corner of an external wall. The wall in front of you is a gable wall, two stories. The joists in the floor above sit on this wall.

 

The old joists sat with their ends on the bricks which have now come away from the concrete blocks behind.  The joists then ran across the floor sat on two extra sleeper walls with the other end sitting on a similar looking set of bricks on the opposite side.

 

Obviously the bricks here have come away from the wall - it's damp crumbly plaster/mortar but the joists in this corner weren't actually too bad (at least compared to other side of room). I don't think these bricks are sitting on anything more than soil (but haven't poked about much!).

 

House built early 1920s so obviously not expecting a great deal in the way of foundations in any case!

 

It is a solid wall except for the bottom 800mm or so which is a dwarf cavity wall.  

 

The outside of wall has for some time been covered up to DPC level with soil/gravel but there's now a small trench dug around the outside to reduce this. Bricks below DPC have lot of efforesence on outside (but I think look to be drying out). 

 

The dwarf wall cavity (bizarrely, as it is so short so no way for this to make a difference to the room) has been insulated with EPS beads at some point. Cavity is only approx 3cm thick. 

 

My question is: are these bricks that have fallen away from the wall part of the actual wall foundations or just built for holding up my joists? 

 

The walls to the left and right don't have them (they otherwise look identical with the concrete blocks running to the base of the wall).  

 

The only other thing to say: there was until late a small piano sitting on the two joists nearest the wall on the left. I'm guessing this possibly didn't help. 

 

No signs of movement in the wall. 

 

My instinctive plan is to try to rebuild this or something like it with engineering bricks or concrete blocks but didn't want to go messing around too much until I understood the function of these bricks. 

 

Thanks for advice as ever.