---
title: "How to Finance a Granny Flat: Loans, Equity & Funding Options"
description: "Compare granny flat financing options in Australia: home equity, construction loans, personal loans and more. Learn what banks need and costs."
source: GrannyFlatCost
sourceUrl: https://grannyflatcost.com/guides/financing-a-granny-flat
lastUpdated: 2026-07-08
citationUrl: https://grannyflatcost.com/guides/financing-a-granny-flat
---

# How to Finance a Granny Flat: Loans, Equity & Funding Options

Compare granny flat financing options in Australia: home equity, construction loans, personal loans and more. Learn what banks need and costs.

Compare granny flat financing options in Australia: home equity, construction loans, personal loans and more. Learn what banks need and costs.

Banks generally lend up to 80% of your property’s current value. The difference between that figure and your existing mortgage balance is your available equity.

A top-up is the simpler option — you ask your current lender to increase your existing loan, no new application, no switching costs. The catch is you stay on your current interest rate, which may not be the best available.

For smaller granny flat projects — basic studios, kit home fit-outs, or topping up a shortfall from equity — a personal loan can fill the gap.

Secured personal loan uses your property, car or other asset as collateral. Lower interest rate (7-10%) and higher borrowing limits (up to $100,000+).

## Key takeaways

## Financing options compared

## Option 1: Home equity (top-up or refinance)

### How it works

### Top-up vs refinance

### Pros

### Cons

## Option 2: Construction loan

### How it works

### Pros

### Cons

## Option 3: Line of credit

### How it works

### Pros

### Cons

## Key Points

- Home equity is the cheapest way to finance a granny flat, with variable rates from 5.8% to 6.5% (as of early 2026). You need sufficient equity: banks typically lend up to 80% of your property value minus your existing mortgage.
- Construction loans release funds in stages tied to build milestones. They require a licensed builder, a fixed-price contract, and council-approved plans.
- Personal loans suit small builds (under $50,000) but come with higher rates (7-14%) and shorter terms (5-7 years).
- CBA is leading the Big Four in granny flat lending, offering up to 60% of contract value during off-site prefab construction (80% for accredited manufacturers).
- A granny flat can add 20-30% to your property value and generate $200-$600/week in rental income, making the financing cost worthwhile for many homeowners.
- Property value: $800,000
- Existing mortgage: $450,000
- Maximum borrowing (80% LVR): $640,000
- Available equity: $640,000 - $450,000 = $190,000
- Lowest interest rate of any financing option

## Frequently Asked Questions

### LMI: is it worth paying?

Lenders Mortgage Insurance is a one-off premium charged when your LVR exceeds 80%. On a $200,000 granny flat loan at 85% LVR, LMI could cost $5,000 to $10,000, added to your loan balance.

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*Source: [GrannyFlatCost](https://grannyflatcost.com/guides/financing-a-granny-flat)*