The biggest obstacle for installing an elevator in an existing building is finding the best location. The toughest challenge, however, lies with making alterations to the structure.
The foundation can prove to be very tricky, but is usually necessary with an in ground hydraulic elevator. This is accomplished by cutting out the lowest levels of concrete floor, excavating (usually by hand), and carrying buckets of soil from the lower level to the outside of the building to be properly disposed of. The existing foundation most likely will need to be shored up or underpinned to keep it stable, as the excavating proceeds.
A new foundation the size of the elevator shaft needs to be formed and poured. The biggest potential problems during this process are often the soil conditions. You would be lucky if you have dry clay to work with. Running water, sand, or pea gravel is occasionally encountered. If water is present, it must be controlled. The sand and pea gravel may be easier to dig then clay but it “caves” in and can undermine the stability of the existing structure.
In extreme cases it may be necessary to drive piling into the ground to hold the unstable soil in place. Driving piles can be difficult due to head room clearance restrictions inside an existing building.
Once the water and soil has been stabilized and/or removed, the elevator foundation can be placed.
It is important to rely on an experienced general contractor in these situations.
