Floorboards sunken and stone step movement

[twilightgirl]

I have two problems, but I'm not sure if they are related.

My house was built in 1900 and I've lived in it for 20 years, but over the last 6 months I've noticed some signs that are worrying me.

My house is on 3 floors with the main house door centrally located and the stairs going straight up the middle of the house and rooms on either side. Over the last 6 months the natural stone step up which leads into the house (with the house when it was built) has moved and seems to have sunk and now there is a gap at the back where it was against the house (gap of 2 inch in some places). As the step hasn't moved before in the 20 years I've lived here it has me worried. Also several floor boards on all three floors of the house (but only on one side of the house) are either moving (and creaking) or have sunken just in one spot.

I'm worried that all the above could be a sign of subsidence. I've checked the walls, inside and out but there aren't any cracks. Does anyone have any ideas why this might be happening, what it is and how to fix it?

thank you.

 

[JohnD]

it is often caused by water leaks washing away the soil and leaving a hole. Are there any water pipes (especially incoming mains), downpipes or wastepipes in that area?

Often you do not see cracks where they are decorated over (wallpaper, skirting etc)

 

[twilightgirl]

it is often caused by water leaks washing away the soil and leaving a hole. Are there any water pipes (especially incoming mains), downpipes or wastepipes in that area?

There is a wastepipe next to the stone step. But behind the wastepipe and stone step is the cellar. (I can see the stone step from the cellar where it joins on to the house and feel the breeze coming in from the gap) so I would have thought that any leaks from the wastepipe would have shown up on the cellar walls in the form of damp or mould. I did check the cellar walls a couple of weeks ago when I went to read the meters (I always do a cellar check for anything odd when I read the meters!) and there wasn't anything unusual showing.