Floors

1. Floors

2. Functional Requirements • Strength and stability • Resistance to weather and ground moisture • Durability and freedom from maintenance • Fire safety • Resistance to passage of heat • Resistance to the passage of sound

3. Strength & Stability • Strength of floor depends on the characteristics of the materials used for the structure of floor. Ex: timber, steel or concrete • Floor must be strong enough to support the dead load and imposed load of the floor. • Timber floor suitable for small imposed load , small spans and for single family building not more than three storey. • Reinforced concrete floor suitable for larger imposed load and wider spans , and both for strength in support and resistance to fire. • Floor should have adequate stiffness against gross deflection under load

4. Resistance to weather and ground moisture • The ground floor of building (heated building) will tend to encourage moisture from the ground below to rise and make the floor damp and feel cold and uncomfortable. • In the former instance, a concrete slab alone may be sufficient barrier. • In the latter instance, waterproof membrane placed on, in, or under the concrete slab will be necessary to prevent moisture rising to the surface of floor.

5. Durability and freedom from maintenance • Ground floors protected against rising moisture and upper floors which solidly supported and protected, should be durable for the expected life of the building and require little maintenance Fire safety • Suspended upper floors should provide resistance to fire for a period adequate for the escape of the occupants from the building. • Estimated periods of resistance to fire is from 0.5 to 4 hours, depending on the size and use of the building. • Generally, timber floor provides a lesser period of the resistance to fire compared to a reinforced concrete floor.

6. Resistance to the passage of sound • The low mass of a timber floor transmit airborne sound more readily compared to a high mass concrete floor. • The sound absorption of a floor can be improved by carpet or felt, and a ceiling by the use of one of the absorbent ‘acoustic’ tile or panel finishes. Resistance to passage of heat • A floor should provide resistance to transfer of heat where there is normally a significant air temperature difference on the opposite sides of the floor. • Both hardcore and a damp-proof membrane on or under the oversite concrete will assist in preventing the floor being damp and feeling cold.

7. Floor members • Joist – any of a number of small, parallel beams of timber, steel, reinforced concrete, etc., for supporting floors. • Sill - continuous horizontal member placed on top  of a foundation wall in order to carry a timber  framework

8. Floor members • Bridging - a brace or an arrangement of braces fixed between floor joists to keep them in place. • Subfloor - a rough floor laid as a base for a finished floor • Skirting – a border, made of wood or tiles, fixed round the base of an interior wall to protect it from  kicks, dirt, etc

9. Floor members • Header - A horizontal structural member that supports the load over a floor, window or door opening. Also known as a lintel.

10. Type of Floor • Concrete on grade • Timber floor - single - hollow • Suspended floor – timber and concrete

11. Concrete on Grade

12. Concrete floor (Solid Ground Floor) Solid Ground can be classified into; • Hard core • Blinding • Concrete bed or slab Concrete block/inner wall Concrete slab Outer wall Sand blinding Damp-proof membrane Hardcore infill;

13. Concrete Floor :Hardcore • Purpose is to fill empty space occurs during excavation. • Act against capillary action of moisture • Usually laid in 100-150 mm layers to the required depth • If necessary, using roller to compact to prevent any unacceptable settlement.

14. Concrete Floor : Blinding • Use to even off the surface of hardcore if a damp-proof membrane is to be placed under the concrete bed. • Generally consist of fine ash/sand/weak concrete • It will prevent the damp-proof membrane from being punctured by the hardcore • Provide a true surface from which the reinforcement can be position.

15. Concrete Floor : Concrete bed • Unreinforced or plane in situ concrete, 100 –150 mm thick • Reinforced concrete, 150mm minimum.

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