We’re the Granny Flat Builders in Perth Who Will Customise to Your Needs.

Whether you’re wanting to build a granny flat to host more room for your extended family, or simply have an additional space for your immediate- growing family to retreat to at the end of a busy day, Sertorio Homes offers an affordable way to build one-, two- or three-bedroom granny flats or detached homes. We use 40 years of experience, a trusted network of tradesmen and the latest in 3D-imaging technology to help you take advantage of this home improvement option.

Sertorio Homes will provide floor plans, including semi-ensuite, kitchen, living and meal areas. We also include built-in robes, built-in laundry behind doors, as well as porch and alfresco areas. All our granny flat new builds, extensions and renovations can be customised to suit your block size and shape and can be built using between 50m2 and 70m2 floor space, subject to planning approval.

Sertorio Homes’ Granny Flats Extensions – The Process

It all starts with our free no-obligation consultation. When you meet with one of our experienced building representatives to discuss your granny flat extension plans, you’ll have the opportunity to customise colour and material selections and specify construction with double brick or thermal walls. We’ll also help you to understand the costs involved with building a granny flat, so you will have peace of mind from the outset.

Once a design, budget and deadline has been discussed and locked in, our team will liaise with your local council to get approval on your behalf before we begin any work. Once we have council approval, the build can begin. We’ll start building your granny flat extension both on and off-site, working to create an incredible space you’ll be proud to live alongside.

Find Out More About Our Granny Flat Extension & Renovation Capabilities in Perth

If you’re looking for a granny flat extension or renovation in Perth, trust the company with more than 40 years of experience. Get in touch with the Sertorio Homes team on 08 9244 1993 for a no-obligation consultation today.


By contacting the Sertorio Home’s office by email or phone, a consultant will contact you to arrange a FREE, no obligation visit to your home.
Leave that to us. We will organise approvals with the council and Water Corporation. We will also organise the survey and engineering details.

As you can appreciate, every council has varying needs and procedures for building. Some councils are also inundated with approvals, although we work closely with councils, there may be an occasional delay with approvals. If you feel that the approval process is unusually long, we recommend that you contact the council direct.

It is advisable to contact your home insurance company to advise them of the renovation. They can advise you on your individual policy requirements.

Each renovation is unique. A time frame will be devised based on your current home and proposed renovation. You will be advised prior to signing the contract the allowable working days to complete works.

This is a personal choice. You should speak with your consultant and site manager before making your decision.

Where possible, sub-contractors to Sertorio Homes will keep mess to a minimum. To ensure you end up with the best possible renovation, it may be necessary to carry out demolition. You will need to cover furnishings and it may become unpleasant for a short period of time. Each renovation is unique and it would be best to speak with your Site Manager to determine your individual needs.

No. Sertorio Homes have qualified designers who will draw up your design plans in-house. Sertorio Homes do not use other architect designs, as we will draw to specification.

Yes you can. Any changes prior to the contract being signed are made in-house at no extra charge. Any changes after contract signed may result in additional costs onto the contract.

No. Any additional tradespeople not directly working with Sertorio Homes will not be covered by insurance. Any damage that they may cause on the renovation will also not be covered by insurance. Speak with your Site Manager to devise the best course of action prior to employing additional tradespeople.

Yes you can. If you decide to provide your own products, please advise your Consultant prior to materials being purchased. If in doubt, speak with your Consultant. Any changes can affect both the price and scheduling of your job.

Practical completion means the renovation is complete, but does not mean it is perfect. In other words, you can live in the house. At time of handover, a Practical Completion inspection will be made by the Sertorio Homes director, and any defects will be noted. These will be rectified within a reasonable time.

Sertorio Homes only carries out renovations in the immediate Perth metropolitan area. Contact our office to confirm if we renovate in your area.

A granny flat is a small self-contained dwelling which can be an ancillary dwelling or attached to the home. It usually has facilities, such as a small kitchen and bathroom, that allow occupants to live in them independently from the main house.

It is possible to rent out a granny flat. It is important to understand which tenancy laws may apply as this will determine both your rights and your responsibilities. For more information about renting out a granny flat, you can contact the DMIRS to assist you.

There are a range of benefits including, to accommodate a growing family, having a place for visiting friends to sleep, and keeping family that may need extra care within reach. It can also add value to your property.

Each granny flat build is unique. A time frame will be devised based on requirements for site preparation and your home design, usually the whole process takes approximately 1 year. Since Covid-19, our industry has faced challenges, which we continue to navigate through with a realistic outlook.

All our granny flat designs are rated 6-star energy efficiency. If you have specific materials in mind, speak to our design team.

No, we do not provide finance options, however we are happy to assist mortgage brokers and banks with providing the required documentation.

The minimum lot size for granny flats in Perth is 450m2. And a granny flat floor area is generally allowed to be 70m2 but can be up to 100m2. Depending on your local council the rules can vary slightly.

All of our new granny flat builds or extensions can be designed to suit your block size and shape. Your floor plan and facilities can be customised to meet your specific needs.

What sets us apart

Our slew of awards, satisfied client testimonials and long-standing relationships with our network of tradesmen speak to how well we’ve delivered on our aim — to be Perth’s premier home improvements company.

You’re always first

With Sertorio Homes, your imagination leads the way. We turn your vision into a reality that will exceed your expectations and become a home to cherish for years to come.

Quality. Always.

Sertorio Home believes in the traditional values of care and craftsmanship. We combine this ethos with modern technology to deliver only the best in custom-designed homes.


With Sertorio Homes and our team of trusted experts, you know what you’re getting. We start by offering a no-obligation consultation, and a fixed-price contract that has a 3D walkthrough of your designs thrown in. With us, you’ll see your home realised before it’s built.

Know your renovation

Renovating means trusting your contractors to treat your home with the same care you do. We share our favourite projects so you know what to look forward to with Sertorio Homes.

Renovate or move?

Wondering which option leaves you with the dream home that suits your lifestyle? Take the quiz that helps you weight up your options based on your needs.

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