Level 1 Diploma in Carpentry and Joinery

1

Construction of Floors

5.1 – 5.3

Unit 101/501: Principles of building construction, information and communication

Level 1 Diploma in Carpentry and Joinery

2

Objectives

To be able to:

5.1 Identify types of floors

5.2 Identify components of solid concrete ground floors

5.3 Identify components of timber floors

Level 1 Diploma in Carpentry and Joinery

3

Purpose of Floors

• Floors are required to be load-bearing: so you can walk on them and so they will stand the weight of stuff being placed upon them (furniture, machinery etc).

But floors are also important for:

• Minimising the transfer of sound between levels (sound deadening)

• Preventing moisture penetration from the ground

• Reducing heat loss between building levels and from the building down into the ground

Level 1 Diploma in Carpentry and Joinery

4

Floors

Floors can be divided into:

• Ground floors

• Upper floors

Level 1 Diploma in Carpentry and Joinery

5

Ground Floors

May be either:

• Solid ground floors; or

• Suspended floors.

Level 1 Diploma in Carpentry and Joinery

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Solid Ground Floors• The floor is supported by the ground

beneath it, not by the house walls. • At least 100mm oversite concrete is

laid upon a levelled and compacted base of hardcore.

• The hardcore is used to raise the level of the top of the oversite concrete to that of the DPC in the walls.

• A damp proof membrane (DPM) is included in the floor construction to prevent capillary action (rising damp) coming up through the floor.

• Insulation is laid into the floor to reduce heat loss.

Level 1 Diploma in Carpentry and Joinery

7

Suspended Timber Floors

Instead of resting on the ground beneath, suspended floors are raised and the load is transferred via beams (joists) to the walls.

Timber joists are usually covered with either a chipboard subfloor or finished with solid timber floorboards or with engineered (composite) floorboards.

Level 1 Diploma in Carpentry and Joinery

8

Suspended Floor Construction

Two common types of modern, wood-based beam that are used:

• Posi-Joist

• I-beamPosi-joist

i-beam

Level 1 Diploma in Carpentry and Joinery

9

Floor Insulation

• To ensure that the floor is thermally insulated, either quilted or rigid insulation is placed between the floor joists. 

• The quilted insulation is supported by netting stapled to the joists

• The rigid insulation can be supported on battens between the joists.

Quilted Insulation

Rigid Insulation

Level 1 Diploma in Carpentry and Joinery

10

Floor Covering

• Engineered wood flooring is composed of two or more layers of wood-based material.

• The increased stability of high quality engineered wood is achieved by running each layer at a 90° angle to the layer above (just like plywood).

• This stability makes it a universal product that can be installed over all types and qualities of subfloors.

Traditional ¾ inch solid timber tongue and grooved floorboard

Engineered floorboards

Level 1 Diploma in Carpentry and Joinery

11

Upper Floors

• Upper floors have been formed from timber for centuries.

• The only difference today is that, for modern upper flooring, floor boards have largely been replaced by chipboard (or OSB) subfloors, while traditional carpentry joints have given way to galvanised straps and hangers.

• In most single domestic dwellings, timber/wood-based floor joists are used in the same way as they are for suspended timber ground floors.

• But in larger, commercial developments and new blocks of flats, timber upper floors cannot provide the required sound insulation and fire protection. Instead, concrete floors are normally preferred.