Speculation on a basement with entirely fake walls

27 Jun 2016
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United Kingdom
I've just bought a house and I've discovered that the basement, which is a lot smaller than the area of the house, seems to be entirely built of hollow walls. I've also noticed parts of the ground floor which aren't over the basement flex quite a lot, considering I'd expect something like concrete under them otherwise. That makes me think the basement actually covers the whole area of the house, and has four fake walls.

The question is, why? Has anyone come across anything like this or can suggest a reason why someone might have done this?

I've ordered an endoscope and I'm planning to drill a small hole and have a look behind the walls rather than go gung-ho and start knocking them down, for fear of there being a very good reason why the basement was shrunk, as it were, but as I have no expertise I can't think what that might be. There's also quite bad damp on one of the walls, and I'm wondering if the reason for that is that the fake walls hide a serious damp problem in the brickwork behind them. I've already had 5 different people joke that someone's stashed their murder victims behind the walls, so hopefully I don't find anything too sinister...

I'll come back with pictures of the walls and what an endoscope shows me behind them when I have them. In the meantime if anyone has a more educated guess than mine I'd be interested to hear what they think.

For the record, the house is about 130 years old, and I have no idea when the interior walls were erected, but I don't think it was recent.
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It was quite usual for older houses to have only a partially-excavated cellar. Typically under the stairs for access, and at the front of the house for coal to be tipped in, but in larger houses sometimes a section under the kitchen for domestic staff to access supplies. Tradesmen, shopkeepers and undertakers sometimes kept stock in the cellar.

You can lift a floorboard in the other rooms to see what's beneath.

Rarely you might find an air-raid shelter or wine storage.

You haven't said if the walls are plasterboard, or L&P, or block, or brick.
I'm not sure what they're made of; plasterboard would be my best guess. They're definitely not brick, they feel and sound far too soft / hollow. I definitely get the feeling there's empty space behind them, though whether that is a cellar the whole size of the house or just a bit of empty space with brick walls a couple of inches behind them, I won't know until I have a look behind them.
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Before you start drilling into those hollow walls you might want to post a few photo's because it's sounds to me like it could be tanking.
In old, Victorian houses, a false wall in the basement usually hides either a) dampness or b) something far more sinister.
As already said hiding dampness is the most likely reason but

I've also noticed parts of the ground floor which aren't over the basement flex quite a lot,

The walls may have been installed to provide some additional support or stiffening to floors which were sagging or too flexible.

If there is no ventilation through the wall then be prepared for possibly strong smells when the wall is breached.
outside look for air brick loose cement round pipes/wires in the area they may give better access with less damage
inside gaps around services like pipes and wires going under the floor
I've gotten some pictures but haven't tried using a borescope yet. Of course the obvious solution has just occurred to me, I don't need to drill any holes in the wall; there are in fact vents, so I can remove one and stick the boroscope through that (oops).






Also excuse the decor; I'm fairly sure whoever decided on this colour scheme must have first had their retinas surgically removed.
It doesn't look tanked to me. Pull that loose paper off in photo 1 so we can see what's behind it as it looks to be plywood.
It looks like mdf with taped joints. You are going to find a right mess behind that lot. Cna you turn the power off to those sockets before you do anything else with the walls?
As last post isolate the power to these sockets if you can.

How about removing the air vents and sticking your hand into the void with a Camera [do not forget to use the Camera wrist strap??

On some of the images there appears to be a load of damp issues?


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