College of North West London presentation; for the National Diploma in Construction

1. Types of ground floors

2. Suspended Ground floor-1890’s
 Joists supported on sleeper & external wall
 Minimal ventilation
 Rising Damp
 No insulation

3. Ventilation for a suspended floor
 Terra cotta air brick through wall

4. Improvements in design
 Joists sitting on sleeper wall with attached
wall plate.
 Incorporation of dpc to prevent rising damp
 Sleeper walls built in ‘honeycomb’ style to
allow extra ventilation
 Extra air bricks

5. Modern Timber Floors
 Timbers are longer
 Extra ventilation
 Insulation incorporated

6. Suspended concrete floors
 Typical block and beam floor
 Quick and cheap to install
 Inverted ‘ T’ shaped beams
 Concrete blocks placed in between them

7. Ground Supported floors
 Solid ground of hardcore supports concrete
floor
 Thick damp proof membrane placed under
concrete with a layer of insulation
 Typical slab – 150mm with reinforcement

8. Upper floors
 To provide extra stability for external walls
 Joists built into wall
 Chipboard typically placed on top of joists

9. Upper floors
 Galvanised joist hangers are built into wall
 Forms a ‘shoe’ or ‘seat’ for joist to sit in.
 Modern prefabricated joists with metal
banding are now commonly used

10. Upper Floor
 Chipboard upper floor with water proof
covering and taped joints