Floors

Question 1

In what 3 situations are suspended concrete slabs or block and beam floors used?

Answer 1

Where the ground:

1. Slopes
2. Has poor or uncertain bearing capacity
3. Is liable to volume change (swells and shrinks)

Question 2

What is the purpose of constructional concrete topping?

Answer 2

To spread the loads on the floor across the structure.

Question 3

A reinforced concrete floor is typically what thickness?

Answer 3

100-300mm

Question 4

The temporary supports for insitu concrete slabs are typically what two materials?

Answer 4

Timber or Steel beams and posts

Question 5

In a Pre-cast concrete beam and block floor, the T-Beams are placed at what centres?

Answer 5

270mm centres

Question 6

Concrete beams must have a minimum bearing of what?

Answer 6

90mm

Question 7

What is a wall plate?

Answer 7

A continuous length of softwood timber that rests along the length of a wall.

Question 8

Timber joists are usually around what thickness and depth?

Answer 8

Between 38 and 75mm thick & 75 to 235mm deep.

Question 9

Timber joists are usually spaced at what 3 sizes?

Answer 9

400, 450 or600mm centres.

Question 10

Floor boards for timber floors are usually what 4 thicknesses?

Answer 10

16, 19, 21 or 28 mm thick

Question 11

Floor boards for timber floors are usually what 4 widths?

Answer 11

65, 90, 113 or 137mm wide

Question 12

Floor boards for timber floors are usually up to what length?

Answer 12

Up to around 5m in length

Question 13

What is timber strutting?

Answer 13

Short lengths of solid wood nailed between joists as a stabilizing method

Question 14

What is an alternative to building in the ends of timber joist?

Answer 14

Using joist hangers

Question 15

What is pugging?

Answer 15

A layer of plaster or sand placed between timber joists to reduce the transmission of airborne sound.

Question 16

What is nogging?

Answer 16

Anogging is a strut used to give rigidity to a structure.

Question 17

What are the minimum dimensions for nogging?

Answer 17

At least half the depth of the joist and at least 38mm thick.

Question 18

What is the minimum height a DPC should be placed at in a wall?

Answer 18

150mm

Question 19

In what situation is it better to build the ground floor slab into the wall?

Answer 19

Where appreciable movement in the soil is anticipated

Question 20

Hardcore is typically how deep?

Answer 20

100-300mm

Question 21

What should a DPM in a floor slab unite with in a wall?

Answer 21

The DPC

Question 22

Vapour barriers should be used on what side of insulation?

Answer 22

The inside face or warm side

Question 23

Pitch mastic and mastic asphalt are both impermeable to water and can therefore serve as what in the ground floor construction

Answer 23

A damp proof membrane

Question 24

In suspended concrete floor construction, T-Beams are usually supported off what?

Answer 24

Brick or concrete sleeper walls

Question 25

In suspended concrete floor construction, how much space for ventilation should be left beneath the T-Beams?

Answer 25

A min of 150mm

Question 26

What does SSL and FFL mean?

Answer 26

1. Structural Floor Finish

2. Finished Floor Finish

Question 27

What is the purpose of a floor screed?

Answer 27

To provide a level surface to which a floor finish can be applied.

Question 28

How is a suspended timber floor constructed?

Answer 28

A timber platform of boards is nailed across timber joists bearing on 1/2 brick (B) thick walls raised
directly off the packed earth, brick rubble or site concrete