Bricks, Masonry, Asphalt and Concrete - Sinking Slab

We recently bought a 50-year-old split level in NJ, knowing it had some kind of problem with the floating concrete slab in the foyer and family room. Our inspector had noticed the gaps between the carpet and floor moulding and suspected the slab had cracked and would need to be replaced.

But when we removed the carpet and two layers of tile, we found the slab was not cracked at all but had presumably just sank -- evenly -- throughout the space, about 1" below the foundation blocks.

Do we need to call in a cement contractor to bring the slab level to the foundation blocks or can we bridge the 1" gap with some kind of subfloor? Our plan is to finish the areas with ceramic tile and wood laminate.

Any assistance would be much appreciated.

There are ways to level floors. Some are a Cement products that can be applied in thin layers, some are self leveling. If the floor is dropped the same all the way through you can use a Cement Board to raise the Floor where you plan on tiling. Adhering the Board with at Thin-Set Mortar. A wood sub floor could be added where your planning on adding wood laminate .

Note: I would have to advise to have a further inspection on the Sinking slab. There is obviously something wrong here and you should seek out the cause before you move on.