Sleeper walls

[McQ]

Looking for some advice on sleeper walls in a mid terrace 1897 house.

In the old plans, at Basement Level, where I have marked blue in the store there is a brick wall where the plans end, but I can see over the top (there is a beam resting on it). Behind it is in the photo below. 1 meter away another brick wall also with a gap, I put my tape measure through, and it hits another wall 1m later. So marked in blue are two more sleeper walls.

There is a lot of dirt (about 1.6m depth) in the cavity. The house is built on a hill, the higher part being North.

A few questions:

Can you remove sleeper walls? They seem very close together for support, 1m.
Will I get in to a pickle if I started to remove that dirt, effectively digging lower at the side walls. I wonder how far down that brick goes at the side (which is the wall to next door).
Whilst it doesn't look like a huge ammount, will removing that amout of dirt, (1.6m deep, 1m long and about 3m wide) take AGES?

Thanks!

 

[McQ]

I've also just noticed, the brickwork on the party wall, has a row of horizonal bricks instead of flat. Wonder why? Could that be the bottom of the foundations?

 

[Cubist]

Well, If Im reading that floorplan correctly - theres a a good to excellent chance those sleeper walls are carrying your ground level floors, the stairs to the first floor and perhaps some part of the rear elevation of the house. You say that the land slopes downhill from the North so the rear elevation wall could be reasonably expected to be circa 2 -2.5 metres below the living room floor level - do you have any access to the space directly behind that wall?

Frankly, I would strongly suggest you consult with a competent surveyor before doing anything at all. You may, albeit inadvertently, severely damage your home AND perhaps your neighbours too.

 

[stuart45]

I've also just noticed, the brickwork on the party wall, has a row of horizonal bricks instead of flat. Wonder why? Could that be the bottom of the foundations?

Bricklayers often use a brick on edge in the footings if they need to bring the height up half a course. It looks like they did it here to match the sleeper wall.

 

[Stevers]

A friend had this situation under his Victorian detached house - also on a slope with semi-basement. I advised him that the dwarf walls were there because the front of the house would only be on normal relatively shallow foundations. He didn't like this answer and proceeded to dig it all out to extend his basement, but then had to underpin the front of his house!

 

[McQ]

Well, If Im reading that floorplan correctly - theres a a good to excellent chance those sleeper walls are carrying your ground level floors, the stairs to the first floor and perhaps some part of the rear elevation of the house. You say that the land slopes downhill from the North so the rear elevation wall could be reasonably expected to be circa 2 -2.5 metres below the living room floor level - do you have any access to the space directly behind that wall?

Frankly, I would strongly suggest you consult with a competent surveyor before doing anything at all. You may, albeit inadvertently, severely damage your home AND perhaps your neighbours too.

On top of the sleeper walls are beams that go all the way across, that have joists reasting on them every foot apart. The house isn't that wide, and the joists above the basement area has no supporting walls or much on it, apart from the lounge floor. Seems exessive support considering the rooms directly above the lounge don't have any extra support apart from the main walls either end of the room (which is a longer distance than the basement area in question).

 

[McQ]

A friend had this situation under his Victorian detached house - also on a slope with semi-basement. I advised him that the dwarf walls were there because the front of the house would only be on normal relatively shallow foundations. He didn't like this answer and proceeded to dig it all out to extend his basement, but then had to underpin the front of his house!

A neighbour with the same house design (originally) dug out much deeper than I would and had to underpin. I'm only looking to go back 2m, but, could involve digging down about 1.2m, which I think will be lower than the foundations. I'm getting a structural engineer to look at it.