Sub Floors

Question 1

What are the minimum clearance requirements for a sub-floor?

Answer 1

150mm
400mm in a termite declared area

Question 2

What are the minimum stump embedment requirements?

Answer 2

.3 x Stump height or 450mm (whichever is greater)

Question 3

How do you determine bearer lamination requirements? What would be the spacing for laminating 90mm bearers?

Answer 3

2 x Depth of bearer
Nail every 180mm

Question 3

How many footing types are there in 1684? What are the kPa requirements for those footings?

Answer 3

5 Footing types
Footings 1-4 - 125Kpa
Footing 5 - 100Kpa

Question 4

If a bearer is joined half on a stump, what are the bearing requirements?

Answer 4

50mm bearing minimum

Question 4

What is the minimum bearing requirement for a joist?

Answer 4

30mm
If lapped then 3 x Joist depth

Question 5

What zone is Melbourne when working out brick ventilation requirements

Answer 5

Melbourne Zone C

Question 6

What maximum offset can a Stump or Bearer be from an internal load bearing wall (LBW)

Answer 6

Offset max 1.5 x depth of joist

Question 6

For sub-floor ventilation, what equation is used for ventilation requirements per m2 of wall?

Answer 6

6000mm2 per meter of wall.
1 vent 230 x 75mm = 52 holes @ 11x11mm = 121 x 52 = 6292mm2

Question 7

How far from an external corner should brick vents be placed?

Answer 7

600mm maximum

Question 8

For loadbearing walls parallel to bearers, how far can a bearer cantilever?

Answer 8

Up to 25% of their allowable span

Question 9

If an inspector is carrying out a sub-floor stump inspection, what are they looking for?

Answer 9

Footing depths
Correct footing diameter
Clean holes
Appropriate bearer span

Question 10

For bearers supporting LBW at right angles, what is the permissible cantilever for 90mm bearer with a sheet roof?

Answer 10

11%
CHECK THIS AS 1684.4 PAGE 35 Table 4.1