Introduction

Becoming a landlord can be an exciting and profitable move — but navigating the buy-to-let mortgage market isn’t always straightforward. Many first-time landlords make avoidable mistakes that eat into their returns, increase risks, and sometimes even block them from scaling their portfolio.

Here are the three biggest mistakes new landlords make with buy-to-let mortgages — and how you can avoid them.

Mistake #1: Underestimating Deposit & Affordability Requirements

Many new landlords assume that buy-to-let mortgages work just like standard residential mortgages. They’re often surprised to find that lenders usually require a 25% deposit (sometimes more) and calculate affordability differently.

• How it works: Lenders use something called an Interest Coverage Ratio (ICR) — typically requiring rental income to be at least 125–145% of the mortgage interest payments.

• The pitfall: If your chosen property doesn’t meet these rental yield requirements, your application may be rejected, even if you have the deposit ready.

👉 Smarter move: Run the numbers before you buy. Use a buy-to-let calculator or speak with a broker to check both deposit requirements and ICR tests. This avoids wasted time and helps you identify properties that lenders will actually approve.

Mistake #2: Choosing the Wrong Mortgage Type

Not all buy-to-let mortgages are created equal — and choosing the wrong product can be an expensive misstep.

• Fixed-rate vs Tracker: Fixed rates give certainty but can be higher; tracker rates follow the Bank of England base rate, which could work for or against you.

• Interest-only vs Repayment: Many landlords opt for interest-only to keep monthly costs low, but this means the capital balance doesn’t reduce. Without a clear repayment strategy, you could face a huge bill at the end of the term.

👉 Smarter move: Align the mortgage type with your investment strategy. If your goal is short-term cashflow, interest-only may suit. If you want long-term stability, repayment or fixed deals may be safer. A broker can help weigh up the options.

Mistake #3: Forgetting About Fees, Taxes & Regulation

Many first-time landlords only focus on the mortgage rate — but the true cost of ownership goes much deeper.

• Stamp Duty Surcharge: Buy-to-let properties attract an additional 3% SDLT.

• Mortgage Fees: Arrangement, valuation, and legal fees can add thousands.

• Tax Changes: Mortgage interest tax relief has been reduced — meaning higher-tax landlords can’t deduct all interest from profits.

• Regulation: New EPC rules and licensing requirements are also on the horizon.

👉 Smarter move: Factor in all costs before committing to a deal. Work with a tax advisor, use realistic calculators, and plan a buffer for regulatory changes. This ensures your investment is profitable in real terms, not just on paper.

If you’re looking for any type of mortgage or finance call NetRent now on 01352 721300 or click here for more information