Solid ground floor

A solid ground floor is a floor laid directly on the ground, with its layers supported by well-compacted earth fill. It is the most common floor in ground-level rooms.

Layers (from the bottom up)

1. Natural/compacted earth: the top soil is removed, then earth is filled in 150 mm layers and rammed to a firm base.
2. Hardcore (brick soling or stone): 100-150 mm of broken brick/stone, well rammed, to cut capillary rise and give a firm bed.
3. Sand blinding: about 25-50 mm, to fill the voids in the hardcore, stop the concrete grout leaking into it and protect the DPM from puncture.
4. Damp proof membrane (DPM): 1000-gauge polythene or a bitumen layer (a 12 mm asphalt coat is also used) to stop ground moisture. It is joined to the DPC of the walls.
5. Concrete bed (PCC): 100-150 mm thick, 1:2:4 or 1:3:6, over the whole room.
6. Screed: 20-25 mm cement-sand (1:4) to level the surface.
7. Floor finish: cement punning, terrazzo, tiles, marble, etc.

     wall        skirting
   +-----+  ___________________ finish
   |     |  ~~~~~~~~~~~~~~~~~~~ screed 25
   |     |  ...................  PCC 100-150
   | DPC |= ___________________  DPM (laps with DPC)
   |     |  ,,,,,,,,,,,,,,,,,,,  sand blinding
   |     |  ooooooooooooooooooo  hardcore 150
   +-----+  ///////////////////  compacted earth

The plinth is normally kept 300-450 mm above the surrounding ground level, so the floor stays above the surrounding earth and rain water. A solid floor is suitable for dry, firm sites.