What's wrong with my house and how do I fix it?!

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I moved into DP's house a few years ago; I've been on the mortgage for about 16 months.

It's a beautiful old Victorian villa that is split into flats; we have the downstairs flat on one side. It's got a basement underneath which nobody uses much. It's got a bit of a damp problem and we have to treat it for mould twice a year; I'm not sure if that's relevant!

I noticed on Sunday that the corner of the hallway outside the bathroom was soaking wet. The carpet has changed colour. It dried overnight, but it smells strongly of outside water; and some new trousers that DP had bought were covered in mud and very wet despite having never been outside.

I braved the basement yesterday and the floorboards appear to be soaked, and the plaster has all fallen away leaving a giant hole. It looks like it's from under our bath. Our bath is sealed and hasn't overflown as far as we know...

Upstairs did have a leak in late Summer last year which ran down our walls and made our ceiling leak, but it was fixed up by insurance. I'm not sure anyone ever checked if it had gone through our floor - our bathroom is tiled, so it seems unlikely?

DP is very stressed about this. I have no idea what to start thinking... Where do I start?! I would rather not involve the building insurance people if it's not to do with the upstairs leak...

Help

Can you walk round the outside (ie not terraced) If you can have a good look at the guttering and the downpipes and see if there are any damp looking patches on the outside walls. Have a look where overflow pipes come out incase one is constantly overflowing.

Do your bath panels come off? If so get a torch and have a good look there too. Try running water from the bath while one of you is in the basement with a torch to see if that makes it worse.

Do you have central heating? Try turning it on and have one of you standing in the basement then to see if you've got a leak from the pipes under the floorboards.

If any of these make you suspicious then that should give you an idea of who to call in (roofer; plumber; heating engineer)

Failing that, then I think you're looking at phoning a builder specialising in damp for advice.

[I'm presuming the house does have a damp proof course?]

Do you have central heating?

Could be a leak under your bath, one of the seals has come away, have you checke under there?

Has the bath waste pipe worked loose? Where were the muddy trousers?

I think you need to check your bath isn't leaking underneath if the basement ceiling is wet underneath the bath.

The leak upstairs was too long ago for that to be the issue I think.

Thank you all!

I'm trying to work out how to get the bath panel off...

The muddy trousers were in the corner outside the bathroom. The bath is on the other side of that wall.

When DP gets home, we'll try turning things on one-by-one and seeing if there's any leakage downstairs.

It's a beautiful house but it seems to be falling apart at times

Why would you not call the insurance company to see if it's covered? When we had a flood in the bathroom they paid for all the repairs including the kitchen underneath.

We had a slow leak on the taps on our bath (purely down to age of the seal). Built up underneath and then voila - hole in the kitchen ceiling one day. Insurance covered it for us, If recommend giving your insurer a call.

We had a tiny wee hole in the bath that could not be seen when empty but with water and a person in opened up and you could hear a drip. Ruined the lounge decor. Drove us mad trying to find it but once the bath panel was off, it was obvious.