Can You Add a Second Storey to Your Perth Home? Drafting and Design Considerations
Yes, many Perth homes can accommodate a second storey. However, feasibility depends on the existing structure, property constraints, planning requirements and project budget.
An upper-floor addition can provide bedrooms, bathrooms, living areas or a home office without reducing valuable backyard space. It can be particularly useful on narrow blocks or properties where a ground-floor extension is not practical.
Before design work advances, the existing home and the applicable planning controls need to be investigated. Early assessment helps determine whether building upward is practical and what the project may require.
Can the Existing House Support a Second Storey?
Structural capacity is one of the first considerations for any second storey addition.
A structural engineer may need to assess the foundations, footings, walls, roof framing and general condition of the house. The purpose is to determine whether the existing structure can carry the additional loads created by the new floor, walls and roof.
Possible structural solutions include:
Strengthening existing footings
Installing new columns or load-bearing walls
Adding structural steel
Reinforcing sections of the ground floor
Using lightweight upper-floor construction
Creating new load paths through the building
The age of a home does not automatically determine its suitability. Some older homes are structurally capable of supporting an addition, while newer homes may still require substantial reinforcement.
Original plans can be helpful, but they may not accurately represent what was constructed. Previous renovations may also have altered the structure. A measured building survey and on-site investigation provide a more reliable starting point for the design.
Early engineering input can prevent time being spent developing a concept that is impractical or unnecessarily expensive.
Stair Placement Is a Major Design Decision
A new staircase affects the layout of both floors. It requires sufficient floor area, head height and safe circulation while connecting logically with the existing home.
Poor stair placement may reduce the size of a bedroom, interrupt a living area or create unused circulation space. Effective placement can improve the overall layout and make the addition feel like part of the original house.
The design should consider:
The amount of ground-floor space required
The arrival point on the upper floor
Natural light around the stairwell
Privacy between living and sleeping areas
Furniture placement and movement
Structural support around the stair opening
Access during future maintenance
Plumbing and other services should also be considered at this stage. Positioning an upstairs bathroom near existing wet areas may reduce the complexity of drainage and water connections. Professional home renovation drafting services can assess these practical requirements while the layout is still flexible.
Planning Controls May Shape the Design
A second storey must respond to the planning controls that apply to the property.
Western Australia’s Residential Design Codes provide planning and design requirements for residential development. Local governments apply these requirements alongside their own planning schemes, policies and site-specific controls.
Common assessment considerations include:
Maximum building height
Street and boundary setbacks
Visual privacy
Overshadowing
Solar access
Streetscape appearance
Roof form
Site coverage
Heritage requirements
Bushfire requirements
Upper-floor windows and balconies often require particular attention because they may overlook neighbouring bedrooms, living spaces or outdoor areas. Privacy can be addressed through window positioning, raised sill heights, fixed screening, obscure glazing or changes to the room layout.
A proposal that satisfies the applicable deemed-to-comply requirements may follow a more straightforward planning pathway. If the design seeks variations, additional assessment or consultation may be required. The correct pathway depends on the property and should be confirmed before detailed documentation is completed.
Local drafting services in Perth can help identify relevant controls and reflect them in the concept design.
Climate and Energy Performance Need Early Attention
An upper floor receives more direct exposure to sun, wind and outdoor temperatures. Without appropriate design measures, it can become considerably warmer than the ground floor during summer.
Important considerations include:
Building orientation
Window size and placement
External shading
Roof colour and materials
Ceiling and wall insulation
Cross-ventilation
Glazing performance
Air-conditioning zones
Protection from western sun
Room orientation should reflect how each space will be used. Bedrooms may benefit from different solar access and ventilation strategies than living rooms or home offices.
Thoughtful residential architectural drafting in Perth can balance comfort, views, privacy and energy performance. These decisions are generally easier and less expensive to resolve during concept design than after approval or construction has begun.
Planning Approval and a Building Permit Are Different
Planning approval and a building permit serve different purposes.
Planning assessment considers whether the proposed addition is suitable for the site. It may examine building height, setbacks, privacy, overshadowing and the effect on the surrounding streetscape.
A building permit addresses whether the project can be constructed safely and in accordance with applicable building requirements. The permit documentation may include architectural drawings, engineering details, energy assessments and other consultant reports.
Some projects may not require separate planning approval if they meet the relevant requirements and exemptions. A building permit will generally still be required for structural additions. Requirements vary between properties and local governments, so the approval pathway should be checked for the specific address.
For further information about the distinction, homeowners can review our guide to planning approval and building permits in WA.
What Does the Drafting Process Include?
A coordinated drafting process typically involves the following stages:
Review the property information and available plans.
Measure and document the existing home.
Investigate planning and site constraints.
Obtain preliminary structural advice where required.
Prepare concept floor plans and elevations.
Refine the layout, appearance and material selections.
Coordinate engineering and specialist consultants.
Prepare planning documentation where required.
Complete working drawings for the building permit and builder pricing.
Detailed residential drafting services should explain both the proposed spaces and how the new construction connects with the existing building.
Consider Cost and Construction Disruption
Second storey additions can involve roof removal, temporary weather protection, structural reinforcement and alterations to the ground floor. Plumbing, electrical systems and air conditioning may also need to be upgraded or rerouted.
Homeowners should consider whether the property can remain occupied during construction. The answer will depend on the scope of work, the builder’s program and how much of the existing roof and interior must be opened.
A realistic budget should include design, engineering, surveys, approvals, construction and a contingency for conditions discovered after work begins.
Start With a Site-Specific Assessment
A second storey can be an effective way to expand a Perth home, but the design must respond to the existing structure and the property’s planning constraints.
Domestic Drafting Service prepares concept designs, council-ready documentation and detailed working drawings for home additions across Perth. We can also coordinate with engineers, surveyors and other consultants where required.
Book a consultation to discuss your property, space requirements and the practical next steps for your project.
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