BCGCA3004B
Construct Wall Framing
Wall Framing
• Building Code of Australia states that
AS 1684.2 Scope
Page 9 Section 1.1
AS 1684.2 Scope
Page 9 Section 1.1
This means that this standard only applies the Residential Buildings (Class 1)
or Garages & Carports (Class 10).
Wall Frame Members
• Parts of a frame perform specific functions
- supporting live & dead loads
- resist Racking Forces
- resist Overturning Forces
- resist Sliding Forces
- resist Uplift Forces
-Most members provide a face to accept
linings (this means that member sizes may be
limited)
Live Load
Dead Load
Racking Forces
Wind
Overturning Forces
Wind
Sliding Forces
Wind
Uplift Forces
Wind
• Timbers Generally Used
- Radiata Pine
- Oregon (Douglas Fir)
- Various Hardwood Species
• Various combinations of
-timbers,
-engineered wood products
-materials such as steel
may be used
WHY?
Galvanized Steel
Strap Bracing
Engineered Timber (LVL)
Lintels
Radiata Pine
Studs
Structural
Steel
Engineered Timber (I Beams)
Deep Joists
• Other more exotic Timbers such as Cypress
Pine may be used.
-Why?
Wall Frames
• Frames are classified into 2 categories
1. Load Bearing – They are structural frames, they
transfer loads from roof or upper floor to the
supporting floor frame. They can be either
external or internal walls.
2. Non Load Bearing –
- do not support any structural loads.
- They support their own weight
- Non structural loads doors and frame, kitchen
cupboards, driers etc.
- support some live loads eg Doors closing.
Therefore there are some minimum
requirements for these AS 1684.2 cl 6.3.5
AS 1684.2 cl 6.3.5
Basic Frame Components
Refer page 187 TAFE Guide
Refer AS1684.2 cl 6.1.2
Frame Member Functions
Plates
•Horizontal members that form the top & bottom of the frame.
•Bottom plate is usually 50mm for unseasoned timber 45mm for
seasoned.
•Top plate is usually the same section size as bottom plate.
•For trussed roof top plates will be 75mm for unseasoned and 70mm for
seasoned
•Top plate may be made up by 2 x 38 (35)
•Thicker top plates means that trusses or upper floor joists do not need
to be placed direct over a stud
Plates AS 1684.2 cl 6.2.2
Studs
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Vertical members placed between the plates
The set the wall height
Studs in external frames resist Wind Loads
Generally Stud sizes are 75mm or 100mm wide by
50mm or 38mm in unseasoned timbers and
70mm or 90mm wide by 35mm or 45mm in
seasoned timbers.
• Required Stud sizes can be found in AS 1684.2
Supplements
Studs Continued
• Several Different types of Studs
- Common
- Door & Window
- Secondary Jamb Studs
- Jack & Short
Trimmers
• Horizontal members fixed between window
studs and door studs.
• Referred to as Sill or Head trimmers
• Usually of the same section size bottom plates
• Openings wider than 1800mm require
trimmers as specified in AS 1684.2 cl6.3.6.6 &
table 6.3
Trimming Studs
•Run from Trimmers to Plates
•Used to block out Narrow Lintel
•Where use in conjunction with Lintel they may take structural loads
•Must be same depth as wall frame to accept finishes
•May also be referred to as “Jack”, “Soldier”, or “Short” studs
Noggins
•Horizontal Member cut between studs to keep them
- straight
- evenly spaced
- prevent twisting
- allows studs to carry higher load
- Maximum spacing 1350mm, there walls upto 2700mm require
only 1 row of noggins
Noggins AS 1684.2 cl 6.2.1.5
Blocking
• Placed at intersections of wall frames
• Normally 3 Blocks per intersection
Blocking AS1684.2
Lintels
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Also referred to as a Head
Horizontal Load Bearing Member between Studs
Purpose is to transfer loads to side of openings
May be made of many materials
- Timber
- Engineered Timbers
- Structural Steel or Cold Rolled Steel Sections
Bracing
• Provide lateral stability of Walls
• Provide resistance against racking forces
induced direct wind loads
• Provide resistance to Roof loads induced onto
top plates.
Bracing Methods
Timber Bracing – 50 to 75 mm x
19 to 25mm checked into and
nailed flush into face of studs.
Braces must be installed in
opposing pairs in external bracing
walls.
This method is virtually never
used today.
Rated 0.8 kN/m
Types of Bracing
Perforated Metal Bracing
- Installed in similar method
as timber brace with a saw
cut into the plates and studs.
The brace is then nailed flush
onto the studs and plates.
Braces must be installed in
opposing pairs in external
walls.
Rated 0.8 kN/m
Types of Bracing
Types of Bracing
Flat Metal or Hoop Iron Bracing
• 19mm Wide x 0.8mm
• Zincalume
• Two braces are fixed in
opposite directions
• Fitted with Compression
Clamps
• Rated 1.5kN/m
Types of Bracing
Sheet Bracing
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Structural Plywood (Must be Stamped)
Hardboard (Masonite)
Fibre Cement
Resists Strong Wind Loads
Can be used on Narrow Panels – Why?
Usually on external walls in cavity – Why?
Minimum 7mm (Not Necessarily Correct)
Must be nailed off as per AS 1684.2
Plate Steel can be used in High Wind Load Areas
Bracing AS 1684.2
Location of Bracing
• AS 1684 cl 8.3.6.6 states
– Bracing should be evenly distributed and be
provided in both directions
– Should be placed initially at corners
Spacing of Bracing Walls
• AS 1684.2 Cl 8.3.6.7 states
– For Single Storey Building or Upper Storey of
Double Storey Buildings
– Maximum distance between bracing wall shall be
9000mm for Wind Classifications up to N2
Plan & Prepare For Wall Framing
• Stress Grading of Individual Wall Frame
Members
• Seasoned Or Unseasoned
Stress Grading
• Refers to the Timbers Strength
• Timber must be able to withstand stress loads
placed on them.
• Overloading may cause straining or failure
• 3 types of stress
Compressive
Tensile
Shear
Note Torsional Stress is not discussed
Stress Grading
• Members Sizes will be determined for span
tables
• Generally for Residential Construction sizes will
not be specified by designers
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Why?
Architect will not want to take responsibility
Engineer will want to charge extra to do this and
Why would a client want to pay for something
that he can get done for nothing
Stress Grading
• Why are members generally specified on
Commercial projects
• AS 1684.2 Residential Timber Framed
Construction Guide
AS 1684.2 Limitations
1.4.4 The Maximum number of storey's of timber shall not exceed 2
1.4.5 The maximum width of a building shall 16 000mm,
Note, if you use AS1684.2 simplified max width = 12 000mm
1.4.6 The maximum wall height shall be 3000mm excluding gable
ends
1.4.7 The maximum roof pitch shall be 35 degrees
Structural pine grading
A3P has announced that it will not proceed
with the introduction of Structural Pine (SP)
grading as previously planned.
Continuing contact with A3P members, timber
merchants, truss and frame fabricators,
designers and specifiers has indicated the
introduction cannot be achieved without
major disruption and unacceptable burden to
industry.
Ordering Timber
• Timber is ordered in lineal meters
may be priced in cubic meters
• Increments of 300mm
• Lengths over 3600mm are charged at higher rate
• Timber should be ordered as required
- avoid unnecessary exposure to weather
- affecting cash flows
- theft
- storage
Material Storage
• Timber should be
stored on gluts
• This allows for airflow
• Care should be taken
in stack sizes
• Stacks can be
strapped for safety
Storage of Materials
• Timber should be stored as close as possible
to work area
What is a Concentrated Load ?
Frame Construction
• Plates
• The size of plates will depend on
1. Floor Joist Spacing
2. Rafter / Truss Spacing
3. Stud Spacing
4. Single or Double Storey
5. Stress Grade of Timber
6. Roof Load Width ?
Roof Load Width (RLW)
Plates
• Seasoned timbers are dressed therefore
trenching not required
• Rough Sawn Timbers such as Oregon,
Hardwood require trenching.
• Housing of plates for studs provides a constant
thickness
• Trenching keeps Top & Bottom plates parallel
• Restrains Unseasoned Studs from twisting
• Trenching usually
appox 10 mm
• Trenching depth is
not critical but what
is left on is.
• Top Plates fully
supported on
masonary walls will
be sized based on a
300mm spacing
Top Plates AS 1684.2
• cl 6.3.4. states that may be a minimum of 35
mm if
1. not required to resist uplift forces (i.e
trusses are nominally fixed and
2. Trusses or Rafters are located directly above
studs or within 1.5 times the depth of the
plate from the stud.
Joining of Plates
• Where plates are butt jointed they may be
joined using a connector plate.
Joining of Plates
• Plates may be Scarfed or Lapped jointed.
• Theses are time consuming and rarely used
Calculate Plate Lengths
• During Fabrication Top & Bottom Plates are
the same length
• Plates should be as long as possible
• Consider manpower available to stand frames
• Remember Top Plate must be continuous
Studs
Stud Sizes are determined by
1. Stress Grade
2. Stud Spacing
3. Rafter/ Truss spacing
4. Wall Height
5. Roof Load Width
6. AS 1684.2 tables only specify 450mm or
600mm spacing. These are the most common
spacing's
Stud Spacing
Stud Spacing Determined by
1. Stress Grade
2. Stud Spacing
3. Rafter/ Truss spacing
4. Wall Height
5. Roof Load Width and
6. If applicable External Sheeting Joints (ie Blue
Board etc)
Studs
• Not all external sheeting require critical stud
placement
• Check with manufactures manual as to
requirements
• Generally studs should be aligned with the
internal face.
Harditek (Blue Board)
Studs
• Stud sizes are determined from tables in AS
1684.2
Calculating Stud Length
• Finished Floor to Ceiling govern stud length
• Minimum Habitable Room is 2400mm Clear
• Floor Finishes
1. Carpet 20mm
2. Timber Flooring 40mm (Depending on Batten)
• Ceilings
1. 10mm Plasterboard
2. 13mm Plasterboard
Calculating Stud Length
• Double Storey building may have FFL (Finished
Floor Level).
• Allowance must be made for structural
members
• Most Importantly Determine if there are any
height restrictions
• Type of Roof Will affect Stud Heights
Top & Bottom Plates = 90 x 45 F5
Step 1 – Determine Floor & Ceiling
Floor Carpet = 20mm
Ceiling Gyprock = 13mm
Step 2 – Calculate Stud Length
Minimum Clearance = 2400mm
Plus Flooring = 20mm
Plus Ceiling
= 20mm
Wall Height
= 2440mm
less Wall Plates = 90mm
Stud Length
= 2350mm
Ground Fl Finish = Timber (40mm)
First Floor = Carpet (20mm)
Upper Level Joists = 200 x 50 F5
Top & Bottom Plates = 90 x 45
Step 1- Determine SFL (Structural
Floor Level)
SFL First Floor = 28.950 (FFL First Fl)
-20 (Carpet)
SFL= 28.930
SFL Ground Fl = 26.200 (FFL Gnd)
- 40 (Timber)
SFL = 26.160
Step 2 – Calculate Height Difference
Ground Floor
SFL First Floor
= 28.930 –
SFL Ground Fl
= 26.180
Height Difference = 2.750
First Floor
Step 3 – Structural Elements
Height Diff
Less Flooring
Less Floor Joist
Less T & B Plate
= 2.750
= 0.017
= 0.200
= 0.090
Stud Length
= 2.443
Ground Floor
First Floor
Carpet Both Floors (20mm) Ceilings 10mm Plasterboard (Allow 20mm)
Dimensions are clear measurements
Lower level plates
Upper Level Plates
Bottom Plate = 90 x 35 F5
Bottom Plate = 90 x 45 F5
Top Plate
= 90 x 45 F5
Top Plate
= 90 x 70 F5
Straightening of Studs
Calculating Door Heights
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On Concrete Slab
Using a standard 2040mm x 820mm
Allow 22mm for Carpet (17mm + 5mm)
2040 mm Door Height
2mm Clearance between Door & Jamb
20mm for Jamb
10mm Clearance between Jamb & Head
15mm Clearance between Jamb & Lintel
Total = 2094mm Say 2100mm
Calculation of Door Width
Calculation of Window
•Check with manufacturer if windows are not on site
•Generally at same height of doors
•Check on elevations for window heights
•15mm Clearance between Jamb & Lintel
•Allow 10mm under sill
Window Width
•Care should be taken when setting out to brick bond!
•Client may want window to line up with internal fitting
•Client may want window dead center of room
Lintels
Construct Wall Frames
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Number Wall Frames
Clock Wise Direction
Internal Walls Left to Right
Top To Bottom
Setting Out Plates
• Confirm Dimensions of Slab/ Subfloor
Select Suitable Timber & Cut to Length
Tack Together
Mark Appropriate ID Number on Plate
• Mark Required Studs – In Following Order
End Studs
Wall Intersections
Setting Out Plates
• If required prepare a storey rod with the
appropriate markings (ie Horizontal & Vertical
Bond)
• Set out position of window and doors studs
remembering to allow for required jamb studs
• If required adjust position to match brickbond
• Set out Common Studs, Jack Studs at required
spacing
Preparing Studs
• Use Storey Rod (Pattern Stud) to cut required
studs
• Mark and check out window and door studs
Wall Frame Assembly
What are Advantages & Disadvantages of Prefabricated Wall Frames?
Assembling Wall Frames
Frame Erection
Nominal Fixings For Bottom Plates AS 1684.2
Bracing