Internal Manhole

[123bashforth]

While having some floorboards replaced in our hallway, we discovered an internal manhole. This was a bit of a shock!

I wondered if anyone knew how common this was, and what problems this might cause. (I hope not many as the floorboards will have to come up again).

Our house is approx. 150 years old, and the internal manhole was never at any time outside the building. We have a serviceable manhole in the back garden.

Waste water pipes pass from our upstairs bathroom and connect with a downstairs toilet. The waste pipe then runs at right angles in the direction of this internal manhole, then changes direction running under our kitchen (a later extension built at a lower level to the main house) then towards the manhole in the garden. Could this internal manhole just be to accomodate the change in direction of the pipes?

I must admit - the thought of drains running under the house worries me. If one collapsed perhaps the kitchen would have to be dug up!

If anyone has come across anything similar - I would love to hear.

Thanks in advance.

[welsh brickie]

a internal manhole is not uncommon,it should be a screwdown airtight cover though.
You need to have access to the drain so screw down the floorboards.