Custom vs Standard Granny Flats: Advice from the Best Granny Flat Builders in Perth

Granny flats have become one of the smartest property investments in Perth. Homeowners are building them for rental income, multigenerational living, or to increase property value. However, one important decision often creates confusion — should you choose a custom granny flat or a standard granny flat?

Both options have clear benefits. The right choice depends on your budget, block size, lifestyle needs, and long-term goals. In this guide, we break down the key differences with practical advice from the best granny flat builders in Perth, so you can make a confident and informed decision.

Understanding Standard Granny Flats

A standard granny flat is built using pre-designed floor plans. These designs are created to meet common council regulations and suit most block types in Perth.

Key Features of Standard Granny Flats

• Fixed layouts with 1 or 2 bedrooms

• Limited design changes

• Faster approvals and build time

• Lower upfront cost

• Ideal for flat, regular-shaped blocks

Standard granny flats are popular with homeowners who want a simple, cost-effective solution without long planning delays.

Who Should Choose a Standard Granny Flat?

A standard granny flat is suitable if:

• You want to build quickly

• Your block has no major constraints

• You are focused on rental income

• You prefer a proven, practical design

For many Perth homeowners, standard designs offer excellent value while still meeting comfort and compliance needs.

What Is a Custom Granny Flat?

A custom granny flat is designed specifically for your block, lifestyle, and personal preferences. Everything is tailored, from layout and room sizes to materials and finishes.

Key Features of Custom Granny Flats

• Bespoke floor plans

• Flexible room configuration

• Premium fittings and finishes

• Designed for complex or narrow blocks

• Higher design freedom

Custom granny flats are often chosen when homeowners want something unique or need to work around site challenges.

Who Should Choose a Custom Granny Flat?

A custom granny flat may be right if:

• Your block is sloping or irregular

• You want a luxury or architectural design

• You need specific accessibility features

• The flat is for family use, not just rental

According to the best granny flat builders in Perth, custom builds are ideal when long-term value and usability matter more than speed.

Custom vs Standard Granny Flats: A Clear Comparison

1. Cost

Standard granny flats are generally more affordable because the design work is already done. Custom granny flats cost more due to architectural planning, engineering, and personalised finishes.

However, custom designs can deliver better long-term value if they maximise space or rental appeal.

2. Design Flexibility

Standard designs allow limited changes. Custom granny flats offer full control over layout, orientation, storage, and aesthetics.

3. Council Approval

Standard designs are often easier to approve because they already align with WA R-Codes and local council guidelines. Custom designs may take longer but can still be approved when handled by experienced builders.

4. Build Time

Standard granny flats usually take less time to build. Custom builds require more planning but deliver a tailored result.

Perth-Specific Factors You Must Consider

Local Zoning and R-Codes

Perth councils have specific rules for secondary dwellings. These include minimum lot size, setbacks, access, and services. Working with the best granny flat builders in Perth ensures your design complies with local requirements from the start.

Block Size and Shape

Many Perth blocks are narrow or have shared access. Custom granny flats work better on challenging sites, while standard designs suit regular blocks.

Climate Considerations

Perth’s hot summers mean insulation, ventilation, and shading are important. Custom builds allow better climate-responsive design, but quality standard builds can also meet energy-efficiency needs.

Cost Breakdown: What to Expect in Perth

Standard Granny Flat Costs

• Lower base price

• Fixed inclusions

• Minimal design fees

• Faster return on investment

Custom Granny Flat Costs

• Design and engineering fees

• Site-specific construction

• Upgraded materials

• Better space optimisation

Hidden costs can include service connections, soil testing, approvals, and landscaping. Reliable builders provide transparent quotes upfront.

Pros and Cons Summary

Standard Granny Flats

Pros

• Affordable

• Faster build

• Simple approval process

Cons

• Limited design choice

• May not suit all blocks

Custom Granny Flats

Pros

• Fully tailored design

• Better use of space

• Higher long-term value

Cons

• Higher upfront cost

• Longer planning stage

How the Best Granny Flat Builders in Perth Add Value

Choosing the right builder matters more than choosing the design type. The best granny flat builders in Perth provide:

• Detailed site assessments

• Honest advice on custom vs standard options

• Council approval management

• Turnkey construction solutions

• Strong warranties and after-build support

Experienced builders help you avoid costly mistakes and ensure your granny flat meets both legal and lifestyle requirements.

Questions to Ask Before Choosing a Granny Flat Builder

Before you commit, ask:

• Are you a registered and insured WA builder?

• Do you handle council approvals?

• Can standard designs be modified?

• What is included in the quoted price?

• What warranties do you offer?

Asking the right questions protects your investment and ensures a smooth build process.

Frequently Asked Questions

Is a custom granny flat worth the extra cost in Perth? Yes, if your block is complex or you want a long-term living solution. Custom designs often deliver better usability and resale value.

How long does it take to build a granny flat? Standard builds are usually faster. Custom builds take longer due to design and approvals.

Can I rent out a granny flat in WA? Yes. Granny flats are commonly rented in Perth, subject to council compliance.

Do standard granny flats meet council rules? Most standard designs are created to comply with WA regulations, but site checks are still required.

Final Verdict: Which Option Is Right for You?

There is no one-size-fits-all answer. A standard granny flat is perfect for homeowners seeking speed and affordability. A custom granny flat is better for those who want flexibility, premium finishes, or need to work around site challenges. The smartest step is to consult with the best granny flat builders in Perth, who can assess your block, explain council requirements, and recommend the most suitable option for your goals. With expert guidance, your granny flat can become a valuable, comfortable, and future-proof addition to your property.