Floor dropped, inadequate support, lifting the drop?

Hi,

I've started replacing the kitchen and noticed some problems. Sorry for the long winded post.

I've done a quick sketch. We're in a bungalow, on a slope so at the back of the house there are some rooms you walk down to, so from the picture the floor in question is in the "middle". The Kitchen Dinner is a U shape area to the right.

The pillar in the middle, supporting 2 beams either side, is in the middle of a 170cm opening downstairs. Looking at old plans I believe it used to be a smaller opening which has been opened up.

Because of the reduced height (1.9m) in the basement rooms, it appears the bodge builders opted to put (woefully inadequate) 2 2m 4x2 concrete lintels in to support the load above - .

The floor had dropped by 2cm (the concrete lintels have bent - not cracked). There are some cracks in the plaster around the central pillar, nothing major to put a finger in to show the 2cm drop, I think the previous owners must have had it replastered a few years ago

I've put in 2 acrow props beneath where the red x's are and taken 0.75cm out of the drop in the floor. The iron rod I've used to crank the acrow can't lift it any more i.e the rod is bending.

I was thinking of getting some more acrows in upstairs - in the middle of the beams, with support beneath, to take some of the load (red x marks the spot). The Plan was to reinstate the wall, or at least a pillar in the middle of the downstairs opening.

I could just stop now, build a wall / pillar, and use leveling compound on the middle of the floor with the dip.

Realistically what are the chances of using more acrows to straighten everything up - cranking them in turn? I've done something similar before where a 2 ton block wall was built on a timber floor which had dropped, using 2 acrows,a Car Jack and putting in a steel, but this must be at least twice the weight.

Or is there another non evasive way / method? i.e without major demolition work which I would have to get someone in for

With the opening underneath, would it be stable enough with a square pillar of bricks for support in the middle of the lintels (directly beneath the upstairs load bearing pillar)?

 

I've not fully read or understood your post but it seems, in my limited experience, odd to have a bungalow on a slope with, what looks like, a full basement?
I know you might be feeling bad about your bungalow issues but things could be getting a bit dangerous so maybe its time to call in a SE (structural engineer)?

 

Its not a full size basement, just on the back, 2 rooms and shower room you walk down to. There wasn't any need to do a full plan. houses on a slope with lower rear rooms are not common, but not uncommon either.

Its ok I've lifted the drop, just 4 or 5mm out now. Its possible this is the most it will go. Using 5 acrow props suitable placed I've taken 15mm out. You turning them in sequence and can lift a lot of weight.

Not feeling bad, pretty good actually. I will get suitable support now, looks like 6" steels will fi. better than 2" concrete lintels

All I planned to do was the kitchen, its going to turn out to be a full refurb as there are other issues I've found lol