The ground floor sits on the ground, so its performance depends on what is underneath more than on the tiles on top.
The Usual Build-Up
| Layer | Practice |
|---|---|
| Plinth filling | Murrum or good soil, compacted in 150–200 mm layers |
| Anti-termite treatment | On the top of the filling |
| Membrane (where specified) | Polythene sheet to block rising damp |
| PCC base | M15, 75 – 100 mm |
| Bed | Cement mortar or tile adhesive |
| Finish | Tiles, granite, etc. |
When a Plain Base Is Not Enough
| Situation | Option |
|---|---|
| Black cotton or expansive soil | Suspended floor slab on plinth beams, or treated filling |
| Deep filling (low-lying plot) | RCC slab on grade, or suspended slab |
| Heavy loads (workshop, parking) | RCC slab designed for the load |
Avoiding Cracks and Damp
- Compact every layer of filling and water it.
- Lay services under the floor before the base.
- Provide joints in large floor areas.
- Cure the PCC base.
- Keep rainwater away from the plinth with a sloped apron.
The Short Version
Compacted filling, termite treatment, an M15 base and a moisture barrier where needed — or a designed slab on poor ground. A flat, dry ground floor starts with the soil under it.
