Structural Design Packages
Fixed-price structural design packages for common residential works — clearly scoped and practical for construction.
from $1,850
1 | Granny Flat & Secondary Dwelling Design
Structural design package for granny flats and secondary dwellings, based on building designs drawings and site information.
Typically includes the following:
slab and footing design (rafts, beams, piers where applicable) or suspended subfloor timber/steel framing
framing layout and tie-down considerations
wind classification checks and member sizing
typical structural details suitable for construction
Form 15 engineering certification
Suitable for new detached secondary dwellings and similar residential structures.
Structural design for external residential structures, including decks, patios, carports, and fly-over roofs.
Typically includes the following:
beam and post layout
footing design and sizing
connection details to existing or new structures
member sizing based on spans and wind classification
typical structural details suitable for construction
Form 15 engineering certification
Suitable for both freestanding and attached structures.
Designed to provide clear, buildable structural documentation without unnecessary complexity.
from $1,200
2 | Decks, Carports & Outdoor Structures
3 | House Raise & Subfloor Design
from $1,900
Structural design for house raising works and new subfloor support systems, based on existing structure and site conditions.
Typically includes the following:
stump / pier layout and sizing
subfloor beam design
bracing considerations where applicable
connection details to existing structure
allowance for typical construction sequencing
Form 15 engineering certification
Suitable for raising existing dwellings and re-supporting structures on new subfloor systems.
Designed to provide practical structural solutions for staged construction and site constraints.
4 | Renovation & Extension Designs
from $1,200 (simple internal modifications only)
from $2,500 (extensive structural modifications)
Structural design for residential renovations, including wall removals, new openings, and alterations to existing dwellings.
Typically includes the following:
beam design for wall removals and new openings
load path assessment and support requirements
footing design where required
connection details and typical structural notes
coordination with existing structure based on available information and visible conditions
Form 15 engineering certification
Simple renovations typically involve isolated wall removals or minor alterations.
Extensive renovations involve multiple structural changes or more complex layouts.
Designed to provide clear and practical structural solutions for modification of existing structures.
from $2,800
5 | Existing Structure Assessment & Certification
Engineering assessment and certification of existing structures or completed works, including retrospective assessment and approval where required.
Typically includes the following:
visual inspection of accessible structural elements
review of available documentation and drawings
engineering assessment of structural performance
written report outlining findings and recommendations
certification (Form 12 / Form 15 where applicable and appropriate)
Suitable for retrospective approvals, completed works, or verification of structural adequacy.
Designed to provide a clear engineering position on existing structures based on available information and inspection.
Request Design Quote
Submit your project details and plans, and we’ll confirm a fixed price and scope based on your project.
We’ll typically respond within one business day.
Alternatively send us an email at: jonathan@williamsstructural.com.au