Ground Floors CONCRETE AND SUSPENDED TIMBER TYPES OF

Ground Floors CONCRETE AND SUSPENDED TIMBER

TYPES OF GROUND FLOORS n Concrete Ground floors n Suspended timber

FUNCTIONS p Support imposed loads p p May differ depending what the building is used for Factory floor needs to be capable of supporting larger loads than that of a dwelling house § Machinery/vehicles § Partitions/furniture § People n n n Provide a level surface Strength and stability Durability p p The material used remain intact surface of floor does not ravel Quality of concrete

FUNCTIONS n Prevent damp rising p As a concrete floor rests on the ground dampness can rise up through it due to capillary action the use of a damp proof membrane can prevent this happening n Prevent heat loss n Allow for finish

CONCRETE GROUND FLOOR: COMPONENTS n Hardcore p p p n Insulation p n 60 mm expanded polystyrene Damp proof membrane p p n Crushed stone dia. 100 mm Layers 225 mm deep Max. Depth 900 mm 1200 gauge plastic sheet Laid on sand blinding Concrete p 1: 3: 6 mix

FOUNDATION & RISING WALLS Rising walls soil Concrete foundation

HARDCORE PLACED & COMPACTED 150 mm min. hardcore

DAMP PROOF MEMBRANE dpm carried up wall and over block work of inner leaf

INSULATION 25 mm insulation 60 mm insulation

REINFORCED CONCRETE SLAB 150 mm min. concrete

WALLS CONSTRUCTED 150 mm min. clearance

FLOOR OPTIONS p The services can be laid in the concrete slab in advance n n This will negate the need for a finished slab It will however mean that there will be a reduced flexibility in dealing with services afterwards p Changes in the service layouts cannot be made without digging up the floor p With the inclusion of the finish screed service plans can be altered even after the walls are built

OPTIONAL SCREED A 75 mm screed can be placed on top of the floor to accommodate service pipes such as central heating and gas

RISING WALLS COMPLETED

HARDCORE INFILL

RADON BARRIER LAID

DPM / INSULATION /STEEL

CONCRETE POURED

POWER FLOATING CONCRETE

CONCRETE GROUND FLOOR: FINISHED

CONCRETE GROUND FLOOR: FINISHED

ALTERNATIVE METHOD p Components: n n n Hardcore Concrete subfloor Dpm Insulation Concrete screed (cement & sand mix)

CONSTRUCTION DETAILS screed dpc/dpm insulation slab hardcore

FUNCTIONS OF SCREED p Provide a level surface for finish n Carpet / Tiles / Timber p Take out any irregularities in the slab p Accommodate services p Pipes

ALTERNATIVE METHOD p Advantages n n n p Screed laid after heavy work No need to protect floor during construction Dpm less likely to be damaged Disadvantages n n n Dpm not continuous from floor to wall Screed must be barrowed in Labour intensive / costly

SUSPENDED TIMBER FLOOR

p When is a suspended timber floor best used? p Used where the depth of fill exeeds 900 mm

Underfloor Ventilation Why do we need ventilation? p To avoid excessive build up of moist air in the underfloor space. p To keep the moisture content of the timber floor members below 20% of their dry weight, to prevent fungal attack taking place. p

Wall plate underside treated Dwarf wall DPC Block sleeper wall 150 mm gaps Gaps left between blocks to allow air circulation 150 mm

How to calculate the number of ventilations opes required, for the house illustrated. 10 m 6 m 31

T 100 50 100 100 MM Insulation 150 mm seated vent through cavity 22 mm Timber floor 125 x 44 Timber Joists DPC 150 Min 75 mm For ventilation GL Min 150 mm 100 x 75 mm wall plate on DPC Dwarf Wall span 2 m between 150 mm Concrete slab Radon Barrier T 150 MM LAYER OF HARD C `3 T