Funding your build
Granny flat finance —
four ways owners actually pay for the build.
Most owners don't write a $121k inc GST cheque. They release equity from the home they already own, or draw a construction loan in stages as the build progresses. Here are the four funding paths we see on real E2ES projects — with a fully worked cash-flow example, the post-completion revaluation play, and the questions every lender will ask.
By Yan Zhu · Co-Founder & Chief Data Officer, E2ES
The four funding paths
Every E2ES client funds their build through one of these four routes. We are builders, not lenders — but we work alongside licensed mortgage brokers every week and can refer you to one who knows granny flat lending inside out.
① Equity release / top-up on your existing home
The most common path by far. Lenders rarely write a construction loan secured against a granny flat alone — the granny flat sits on the same title as your main house, so there is no separate security to lend against. Instead, your broker tops up (or splits) the existing mortgage against your home's current equity. If your house is worth $850k and you owe $500k, most lenders will let you borrow up to 80% of value ($680k) — releasing up to $180k without Lenders Mortgage Insurance. The funds land as cash, so you can pay E2ES's staged invoices directly with no bank inspections between stages. Fastest approval of the four paths, usually 2–4 weeks.
Best forOwners with 20%+ equity in their current home — which is most owners who bought before 2022.
② Construction loan
The structured route: 20% of the ex-GST build price plus all GST in cash (~$33k–$46.5k for the Victorian 34 m² / 60 m² illustrations), with 80% of the ex-GST build price drawn down in four stages that mirror the build — slab, frame, lock-up, fit-out. You pay interest only on what has been drawn, at investment interest-only rates of about 6.3% p.a. (2026 market), so the interest bill ramps up gradually across the three-month construction programme instead of hitting on day one. The lender sends a valuer to sign off each stage before releasing the next payment. Slower to arrange than a top-up (allow 4–6 weeks) and more paperwork, but it suits owners who want the build debt ring-fenced from the family home loan.
Best forInvestors who want the build debt separated, or owners whose existing loan can't be topped up.
③ SMSF (self-managed super fund)
Possible, but the most heavily regulated path. Borrowing inside super must comply with section 67A of the Superannuation Industry (Supervision) Act — a limited recourse borrowing arrangement (LRBA) — and the ATO takes the view that borrowed SMSF money generally cannot fund improvements that change the character of an existing asset, which catches many granny flat builds on an already-owned SMSF property. If the fund buys the property and builds with its own cash (no borrowing), the rules are more workable. Two hard lines either way: you and your relatives cannot live in it, and you cannot rent it to related parties. This is licensed-advice territory — talk to an SMSF-accredited financial adviser and accountant before signing anything. We can refer you to brokers who work on SMSF granny flat projects.
Best forTrustees with an SMSF-held investment property and professional advisers already in place.
④ Cash
The simplest path: pay the staged invoices as they fall due, keep the asset unencumbered, and keep 100% of the rent. On the 34 m² plan the target rent is $380/wk — $19,760 a year before any costs — against a $121k inc GST all-in build price including connections. Rent divided by the build price is not a rental yield (it leaves out the land, vacancy and every holding cost). E2ES owner-stated upper range (21 October 2026): rooming-house gross yield of up to 13% in Melbourne and up to 15% in Queensland — not a forecast; the result depends on site, rents, vacancy and costs. The trade-off is opportunity cost: many investors deliberately borrow anyway, because the interest is tax-deductible on an income-producing build and the preserved cash funds the next deposit.
Best forDownsizers, business owners with cash reserves, and owners who value simplicity over leverage.
Victorian worked example — 34 m² Compact Studio, financed
The numbers below use the E2ES fixed price and a illustrative interest-only rate. Your rate, rent and costs will differ — treat this as a template, not a promise.
| Build price (34 m² Compact Studio) | $121,000 inc GST |
| Cash contribution (20% ex-GST + all GST) | ~$33,000 |
| Amount financed | $88,000 |
| Rate assumption (investment, interest-only) | ~6.3% p.a. |
| Interest cost | ≈ $107 / week |
| Typical rent (34 m² studio, metro Melbourne) | ≈ $380 / week |
| Net cash flow before running costs | ≈ +$273 / week |
Before running costs means before property management (~7–8% of rent if you outsource), insurance, extra council rates, maintenance and vacancy. Even with a conservative $70–$90/wk allowance for all of those, the studio remains solidly cash-flow positive from the first tenant — the rent covers the loan roughly 3.5 times over.
After the build: revaluation, refinance, depreciation
The OC-triggered revaluation. The moment your occupancy certificate (OC) is issued, the granny flat stops being a construction project and becomes recognised, income-producing floor area. Lenders will now order a new valuation of the whole property. A compliant, certified second dwelling is usually counted in that valuation, but how much it adds depends on your lot, the valuer and the market at the time. We do not estimate it, and no one can promise it will exceed what you spent.
Refinancing to release the uplift. That revaluation is not just a number on paper. Many E2ES investor clients refinance within 1–3 months of OC: the higher valuation drops their loan-to-value ratio, which unlocks a further equity release — often enough to cover the deposit on the next investment property. The granny flat effectively becomes the deposit factory for purchase number two. A broker can usually run the top-up against the new valuation in 2–4 weeks.
Depreciation. A brand-new granny flat is one of the most depreciation-rich assets per dollar in Australian residential property, because 100% of the build is new construction. As a rule of thumb, an illustrative $110k ex-GST capital-works base (within the $121k inc GST build price) supports roughly $2,750/yr in Division 43 capital works deductions (2.5% p.a. over 40 years), plus Division 40 plant-and-equipment deductions (hot water heat pump, air conditioner, appliances) that are front-loaded in the early years. Order a quantity surveyor (QS) depreciation schedule after handover — it costs $600–$800 once, is itself tax-deductible, and typically pays for itself several times over in year one. Your accountant applies it at tax time.
Granny flat finance FAQs
Less than most people assume. On the 34 m² plan you need roughly $33k in accessible cash or equity, and the ability to service an $88k loan — about $107/wk in interest at ~6.3% interest-only. Because most lenders also count 70–80% of the expected rent (~$380/wk) toward your serviceability, the build often improves your borrowing position rather than straining it. A broker can give you a firm answer in one conversation using your payslips and current loan statements.
Often, yes — through equity rather than new serviceability. If your home has risen in value since you bought, an equity release re-runs the numbers against today's valuation, and the assessed rent from the granny flat is added to your income side. Owners who were 'maxed out' on 2021 figures frequently find that a 2026 valuation plus $380/wk of assessed rent changes the answer. If the equity path is genuinely closed, the remaining options are cash, a family guarantee, or waiting one valuation cycle.
No — and it would be wrong for us to. E2ES is a builder, not a licensed credit provider, so we never handle your loan application or give credit advice. What we do is refer you to licensed mortgage brokers we work alongside regularly, who already understand our fixed-price contract, our staged payment schedule, and how lenders treat granny flats. The referral is free and there is no obligation to use them.
A construction loan releases money in stages matching slab, frame, lock-up and fit-out/completion. A lender may require a valuer to sign off each stage before releasing funds. E2ES uses a fixed programme of four weeks of paperwork followed by three months of construction, with contract payments matched to the agreed milestones. If the owner funds the build through an equity release, the funds are already available for paying the staged invoices; the lender confirms its own requirements.
Bank valuers treat a compliant, council-approved, self-contained secondary dwelling as extra living area and extra income — both of which raise the valuation — but they typically credit it at less than a comparable amount of main-dwelling floor space, and policies differ bank to bank on how much of the rent they will count. Two things protect your valuation: a Class 1a building permit with an occupancy certificate (never an unapproved conversion), and a formal lease showing the rent. An experienced broker will steer your application to the lender with the friendliest granny flat policy that week — this is exactly the kind of nuance that makes the broker referral worth taking.
Yes, with a haircut. Most lenders count 70–80% of the assessed market rent (shading for vacancy and costs) once the dwelling is approved and either leased or supported by a rental appraisal from a property manager. On $380/wk that is roughly $266–$304/wk of assessable income — often enough to swing a borderline application. A few lenders are more conservative on secondary-dwelling rent than on a standalone investment property, which again is a lender-selection question for your broker.
Not at the first meeting. The sequence is: free site visit and fixed-price proposal (no money), contract signing (initial deposit — capped at 5% under the Master Builders HC 8 contract for builds over $20k), then the staged payments across permits and construction. Your finance should be approved before you sign the building contract, so start the broker conversation 4–6 weeks before you want the build to begin. The ~$33k 'cash down' figure on the 34 m² plan is spread across those stages, not paid up-front in one hit.
Yes — and most investor clients should at least run the numbers. Once the OC is issued and the property is revalued, you can consolidate the construction loan into your main mortgage at standard rates, or keep it split for clean tax accounting and simply reprice it. The lower loan-to-value ratio after revaluation is also the trigger point for releasing equity toward your next purchase. Allow 2–4 weeks and one valuation fee; your broker will tell you whether the rate saving or the equity release is worth more in your case.
The equity release / mortgage top-up — usually 2–4 weeks to approval, because the security (your existing home) is already known to the lender and the funds land as cash with no stage inspections. A construction loan takes longer to arrange (allow 4–6 weeks) and adds a valuer sign-off at each of the four drawdown stages. Whichever path you take, licensed brokers arrange the lending — E2ES is a builder and only makes referrals.
Yes. The free site visit and fixed-price proposal cost nothing, so take the written proposal to a broker first and start that conversation 4–6 weeks before you want the build to begin — then sign the building contract once approval is in place. The initial deposit at contract signing is capped at 5% under the Master Builders HC 8 contract for builds over $20k, and the remaining cash-down is spread across the staged payments, so nothing large falls due before your finance is settled.
Important disclaimer
E2ES (Optima Real Estate) is a residential builder. We are not a licensed credit provider, mortgage broker, financial adviser or tax agent, and nothing on this page is credit, financial, tax or investment advice. All rates, valuations, rents, deductions and cash-flow figures are general illustrations only — they do not take your personal objectives, financial situation or needs into account, and they will differ from your actual outcome. Before making any borrowing or investment decision, obtain advice from an Australian Credit Licence holder (for lending), a licensed financial adviser (for SMSF and investment decisions) and a registered tax agent (for depreciation and deductions). Where we refer you to a broker or adviser, they are independent licensed professionals and you are under no obligation to use them.
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