Floor, Wall and Roof Framing - AS1684.4

This article provides guidelines for floor, wall and roof framing as per AS1684.4 standards. It covers suitable construction, foundation, framing members, wall materials, roof span and more. The article also includes information on underpin, roof truss bracing and BCA document. Suitable for students studying construction and engineering courses.

Floor framing - AS1684.4
Q
no Answer Reason or Explanation
1i Suitable The building is to be built in a city whose perimeter
has an estimated over 250,000m2 of open spaces.
ii Suitable
The plan is partly rectangular and partly L-shaped
which is within the physical limits for timber-
framed construction
iii Single and two storey construction Two storey in the maximum load that timber can
support due to its strength
iv Suitable Less than 16M which is the maximum
v Suitable Within the provided limits of 3000mm
vi Suitable Within the standard limits
vii Suitable Roof pitch is 30⁰ which is within the 35⁰ maximum
limit range
2 Yes
The site on which the building is to be constructed
has such topography that is able to support the
structure
3 450mm
4 300mm. The information would be
found in the BCA
5 There would be no need of filling
The floor of the building would be raised hence pad
foundation would be used in the construction of the
foundation.
6 50kPa,
Controlled fill is an embankment
operation where the depth of
lift, moisture content and
compaction equipment are
closely regulated a by
inspection and specification.

A rolled filled is an
embankment of the rock or
earth where the material is
put in layers and compacted
using rollers. kPa is a unit
for measuring pressure.
Allowable bearing pressure
refers to the ability of the
soil to support the load of a
building and its contents
excluding excessive
settlement.
7 Diagrams unavailable
8
A DPC is a barrier that prevents
moisture from passing through a
structure by capillary action
through the rising damp
phenomenon.
9
Thin material pieces of impervious
materials that are installed to stop
water passage through and into a
structure or to be as part of the
weather resistant barrier system.
10 Windows, chimneys, vent pipes,
walls, door openings, roofs
11 Size of floor Framing Members - identify the location of timber stumps, bearer, joists
and the ledger on the plan below.

Q11 continued… Size the members.
AS1684 table
used
Timber
stress grade
Span
mm
Spacing
mm
Single or
continuous
span used for
sizing?
Size
(mm x mm)
Post
(note:
footing
type 2)
F11 1400mm 100 x 50
Bearers Unseasoned
F11
Joist Unseasoned

F11
Decking
You will need
to do a little
research (not in
AS1684)
Australian
Spotted gum 175 x 50
Wall framing - AS1684.4
Q.
no. Answer Reason or Explanation
12
40 mm. this
information can be
found in the BCA.
13
a 1200 mm crs
b
600 mm crs
c 450mm crs
14
a 80 mm
b 120 mm
c 90mm
15 100 mm x 75 mm
16 A small size
wouldn’t suffice
MPG10 is the smallest grade of underpin hence would not support
the full load successfully
17 MPG12 T2 H2
The western side of the building is where the garage is located.
This side would require stronger wall materials in order
to support the load of the roof.
18 Reducing the
number of

openings in the
east-west direction
Maximizing the
number of
openings in the
north-south
direction
19 None The frames would be able to resist the gravity loads together
None The frames would be able to resist the gravity loads together
20a 3.6M
b 3.6M
c 3.0M
d 2.7M
e 353mm
f 2600mm
g 1219mm
21
Note: every student will have a different layout. Ensure they have sufficient bracing and
comply with the Rules and allowances of Clause 8.3.2.3
See suggested layout provided. Type A 14 units East-West; 22 units North-South
Ensure that wind bracing is placed in walls parallel to the wind direction that is being
resisted.
Roof framing - AS1684.4
22a) 47 x 220
b) 5M, the span should be a single span
c) 1.84M
d) 190 x 45

e)

23a) 16M The roof overlaps on either sides of the wall by a
minimum of 600mm
b) 2.6M As of the size of the rafter used which is 170 x 45
c) Underpin is needed
Being a continuous roof span, the roof would need to
be supported at various points in order to achieve the
required design strength.
d) 140 x 45
With an underpin, there would be an additional
support introduced hence there would be need for
smaller rafters as the support required has been
supplemented by the underpins.
e)
5400-45=5345
5345/2=2672.5+200+300=3172.5
3172.5*1.55=4917.4M
The thickness of the rafter is subtracted from the span
and then divided by 2. The thickness of the brick wall
and that of the suffice is added to the result which is
then multiplied by 1.55.
f) The overhang is compatible with
the standard birdsmouth notch
The span of the overhang is within the 2x6 range of
the birdsmouth notch
g) Roof truss bracing Required to stabilize the gable ends
h) BCA document