Upsizing in Dover Heights: how to set a safe borrowing limit

If you already own in Dover Heights and want a bigger family home, the real question isn’t “How much will the bank lend?” but “How much more can we safely borrow without wrecking cashflow?” For most Eastern Suburbs families, a sensible ceiling is the loan size that keeps total home repayments around 30–35% of net household income and leaves at least 6 months’ living costs in cash or offset.

Step 1: Define your “safe, not maximum” borrowing limit

Lenders will often approve more than is comfortable. You need a separate, stricter rule for your family.

Practical safety rules for Dover Heights upgraders:

1. Repayments cap: Aim to keep combined home loan repayments at 25–35% of after‑tax household income (consistent with renovation guidance used across the Eastern Suburbs).
2. Buffer rule: Hold 6–12 months of living costs plus repayments in offset or easily accessible cash.
3. Equity rule: After upsizing, keep your family home LVR at or under ~80% where possible, to avoid or minimise LMI and protect flexibility. See also the broader equity framework in How Much Equity Can You Safely Tap From a Dover Heights Home?.

If the bank will lend more than these rules allow, treat the excess as off‑limits.

Start with clear numbers on equity, repayments and buffers before looking at bigger homes.

Step 2: Map where you are now (equity and cashflow)

2.1 Work out usable equity

Start with a conservative estimate of your home’s value.

• Current home value (realistic, not agent’s top number)
• Less: current mortgage
• Equals: total equity

Then apply a safe LVR target.

Example – current position

• Dover Heights house: $3.0m (conservative)
• Current mortgage: $1.4m
• Equity: $1.6m
• 80% of value: $2.4m
• Maximum debt at 80% LVR: $2.4m
• Headroom (extra debt before hitting 80%): $1.0m

That $1.0m is the theoretical bank‑friendly headroom. Your real limit will be lower once you apply your income and buffer rules.

2.2 Check income versus repayments

Next, compare current and potential repayments to your income. Use an interest rate at least 2–3% above today’s to mirror how lenders stress test (APRA currently expects a 3% buffer).

Illustrative rate assumptions (not offers):

• Current rate: say 6.0% p.a. P&I
• Stress‑test rate: 8.0–9.0% p.a.

2.3 Worked example – how much extra debt looks sensible?

Assume:

• Combined after‑tax income: $26,000 per month
• Current mortgage: $1.4m over 25 years, 6.0% P&I
• Repayments ≈ $9,040 per month
• That’s 35% of net income already.

If you add another $600k (total $2.0m debt) at the same term and rate:

• New repayments ≈ $12,915 per month
• That’s almost 50% of net income – too high for most families.

A safer upgrade might be an extra $300–400k, especially if school fees or a future income drop are on the horizon.