--- title: "Solid ground floor" subject: "Building Technology" chapter: 7 key: "semester_6/building_technology:solid-ground-floor" source: https://www.bctengineer.com/q/semester_6/building_technology/solid-ground-floor site: BCT Engineering --- # Solid ground floor Building Technology · Chapter 7: Flooring - Asked in: 2078 Baisakh, 3 marks; 2071 Bhadra, 8 marks (asked 2 times) - Video: [Finally! I started building my own house. Pt1- foundations and concrete slab](https://www.youtube.com/watch?v=Vqmb7RAuh4A) — lignum - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/building_technology/solid-ground-floor - Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-7 ## Question Describe about solid ground floor with sketch (draw a section of solid ground floor with necessary details). ## Short answer Solid ground floor layers from bottom: compacted earth, hardcore (100-150 mm), sand blinding (25-50 mm), damp proof membrane, concrete bed (100-150 mm, 1:2:4), screed (20-25 mm, 1:4), and floor finish. Plinth kept 300-450 mm above ground level for drainage. ## Answer 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. ```text 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. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What is the order of layers from the bottom? A. Compacted earth, hardcore, sand blinding, DPM, PCC, screed, finish B. Hardcore, earth, PCC, sand, screed, DPM C. Earth, PCC, DPM, hardcore, finish D. Screed, PCC, hardcore, earth Answer: A. Bottom to top: earth, hardcore, sand blinding, DPM, PCC, screed, finish. (Key point: Layer order) 2. What does the hardcore do? A. Levels the surface B. Cuts capillary rise and gives a firm bed C. Gives the finish D. Binds the concrete Answer: B. Rammed broken brick/stone of 100-150 mm. (Key point: Hardcore role) 3. Why is the DPM joined to the wall DPC? A. To bond concrete to wall B. To support skirting C. To give a continuous barrier against moisture D. To reduce load Answer: C. A continuous barrier stops ground moisture. (Key point: DPM joined to DPC) 4. What is the minimum plinth height above ground? A. 50 mm B. 150 mm C. 1000 mm D. 450 mm Answer: D. The answer states at least 450 mm (usual 300-450 mm). (Key point: Plinth height) ## Related in Building Technology - [Solid and suspended ground floor](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Asolid-suspended-differ) — Building Technology, chapter 7, asked 2× - [Ground floor with mosaic tiling and external wall](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Amosaic-ground-floor-wall) — Building Technology, chapter 7 - [Suspended ground floor](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Asuspended-ground-floor) — Building Technology, chapter 7, asked 2× - [Suspended ground floor; tile flooring](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Asuspended-ground-floor-tile) — Building Technology, chapter 7 ## Related in other subjects - [Hollow section replacing solid compression member](https://www.bctengineer.com/question.md?key=semester_3%2Fstrength_of_materials%3Ahollow-replace-solid-compression-member) — Strength of Materials, chapter 6 - [Uplift at inside corners, 50 m floor weir](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Aweir-uplift-two-inside-corners-50m) — Irrigation and Drainage Engineering, chapter 5, asked 2× - [Restrained floor slab, 4x5 m](https://www.bctengineer.com/question.md?key=semester_7%2Fdesign_of_rcc_structure%3Arestrained-floor-slab-4x5-m) — Design of RCC Structure, chapter 9