Sagging floor and cracks

Gazelle1985

Hello,

We moved into a 1930s semi in May. Homebuyer survey carried out in February reported no problems with cracks etc.

The house has an extension which was built over 20 years ago. I've noticed, in the last two months, that the floor (which is LVT over concrete) has started to sag in one particular place in the kitchen, which is approximately where the extension is. It's dropped around 1cm at the lowest, and the sagging area is about 1 meter in width. The floor isn't sagging anywhere else that I can see.

I'm aware that the long drought over the summer has resulted in a lot of subsidence claims, and I'm worried that this might be what it is. There are no cracks downstairs, but I have noticed vertical cracks around the doors upstairs and there are a few horizontal cracks in the old part of the house. One door has started sticking a bit (the one nearest the extension).

They are all hairline cracks and none are diagonal, although there is one in the landing which goes around where the RSJ must be - where the old house meets the new house. The cracks inside the bedrooms have appeared since the summer, but it's impossible to know whether the ones in the landing are new, as the whole area was covered in woodchip wallpaper, which we have removed and had the walls replastered in July.

There is also a vertical crack in the render outside where the old house meets the new house.

Does this sound like subsidence? The only other thing to mention is that we had a new kitchen installed, and a new dishwasher put in, and the sagging floor is quite close to it. Could it be leaking?

Thank you.