Just need to ask advice on this. Had a new extension to the rear of our house. It's a 60s build with suspended timber floors. For the ease of running existing services to the new area, we are continuing with the suspended timbers. A new sub base was laid down in the extension, butted up against what appears to be the old slab running under the house. The sub soil is heavy clay.
The extension wasn't covered during the recent heavy rain so it ended up filling like a bath. Fortunately there's now some cover and we've been able to get the water out however it's been noted that when empty, the water was rising up where old meets new and that the water is clear and cold.
The sub base is probably 100mm below the outside ground level and with a high water table during heavy rain, it appears to be finding a level inside. There appears to be a point along that line where there is a hole filling with water and at that point there is no concrete at all (on the old slab side)
Anyone with any ideas on what can be done to rectify before I put a floor down? I don't want a spring under the house every time it rains.
For reference, the wall to the right of shot is the old house wall which now becomes a sleeper wall to take the floor joists. Top of shot you can just make out the new dpc and blockwork.
The extension wasn't covered during the recent heavy rain so it ended up filling like a bath. Fortunately there's now some cover and we've been able to get the water out however it's been noted that when empty, the water was rising up where old meets new and that the water is clear and cold.
The sub base is probably 100mm below the outside ground level and with a high water table during heavy rain, it appears to be finding a level inside. There appears to be a point along that line where there is a hole filling with water and at that point there is no concrete at all (on the old slab side)
Anyone with any ideas on what can be done to rectify before I put a floor down? I don't want a spring under the house every time it rains.
For reference, the wall to the right of shot is the old house wall which now becomes a sleeper wall to take the floor joists. Top of shot you can just make out the new dpc and blockwork.