It sounds like you've got a property with some significant issues, especially with the subsidence and lack of paperwork confirming it. The fact that it's on clay soil and a steep hill could make ongoing stability concerns more challenging. For a property like this, especially an Edwardian semi, there’s often a mix of potential risks: from foundation movement to aging infrastructure (plumbing, electrics, windows). The lack of planning records could also be a red flag, but it might be worth having a detailed structural survey done by a specialist in subsidence or older buildings.

Anyone with experience in these types of properties will likely emphasize thorough inspections and may recommend things like stabilizing the foundation, replacing the roof and windows, and modernizing the systems (heating, electrics). It's definitely a lot of work, but it's manageable with the right experts.

Thanks so much. There is certainly a lot of work that needs doing. If the worst case scenario is that the property needs underpinning, how does that work with a different person owning the downstairs flat. Would the property be habitable while underpinning is being done? Currently it's tenanted.

If underpinning is needed, it usually affects the whole building, so both flat owners (or the freeholder and leaseholders) must agree on and share the cost. It’s a major structural job that requires a structural engineer, Building Control approval, and often a Party Wall Agreement. The work can be noisy and disruptive, and while parts of the property might remain habitable, tenants often need to move out temporarily. You’ll also need to notify your insurer, as proper documentation is essential for future cover or resale.

but if you want to try possibility check your local authorities if it allowed then check with your contractor if it safe living there where reconstruction proceed and will they be able to do it in different stages that could leaves a portion of liveable area in each stage, do this after they go through full survey, then check your insurer if you take this option they might not cover property damage during reconstruction or injury caused by living in the property, then last convinces tenants, makes agreement on the shared cost ratio and timeline (like if they go to work or isnt in the city for trip then that day can be used for continue reconstruction) convinces them by suggesting it also perfect opportunity to do other improvements the others tenant wanted