Switching to a Buy to Let Mortgage: Your Complete Guide to Making the Move
Many homeowners reach a point where they want to turn their existing property into a rental. Whether you are relocating, upsizing, or simply exploring investment opportunities, the idea of switching to a buy to let mortgage is becoming increasingly common. But how does the process work, when do you need a remortgage, and what do lenders expect?
This clear and practical guide explains your options, criteria and preparation steps. This article provides general information only and does not offer regulated mortgage advice.
Can You Switch a Residential Mortgage to a Buy to Let?
Yes. Homeowners typically have two main routes when renting out a property:
- Consent to Let – temporary permission from your current lender.
- Buy to Let Remortgage – a full switch onto a buy-to-let mortgage.
The right option depends on how long you intend to let the property and your lender’s rules.
Option 1: Consent to Let
Consent to let is suitable if you want to let the property short term and keep your existing residential mortgage.
When lenders may approve consent to let:
- You are relocating for work
- You are moving in with a partner
- You plan to return to the property
- You are letting temporarily due to market conditions
Key features:
- Often granted for 6–12 months, sometimes longer
- May involve a fee or a slight rate adjustment
- Not intended for long-term rentals
- Lender retains the right to review or withdraw permission
This can be a flexible choice for unexpected changes, but not a permanent solution.
Option 2: Switching to a Buy to Let Remortgage
If you plan to let the property long term, lenders expect you to remortgage onto a buy-to-let product.
What this involves:
- A full buy-to-let mortgage application
- Rental income used for affordability
- Different product rates and criteria
- Lender valuation confirming achievable rent
A buy-to-let remortgage typically offers better stability and aligns the mortgage product with your intended use.
Why Switch to a Buy to Let Mortgage?
Homeowners switch for several reasons:
- Moving to a new main residence
- Starting a property investment portfolio
- Not wanting to sell the current home
- Turning negative equity into rental income (depending on lender rules)
- Generating passive income
- Preparing for long-term financial planning
Switching can create a smoother transition into the rental market, especially if you already have equity in the property.
Lender Criteria When Switching to a Buy to Let Mortgage
Lenders apply standard buy-to-let rules, plus additional scrutiny if you are switching from residential.
1. Rental Income Stress Tests
Lenders must see that rent covers the mortgage interest under stressed rates.
Typical requirements:
- 125%–145% ICR for limited companies
- 140%–170% ICR for individuals
Stress rate examples range between 5% and 8%, depending on the product.
2. Minimum Personal Income
Most lenders require:
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- £20,000–£25,000 minimum income
- Stable employment or trading history
Even though rental income drives affordability, personal income shows broader financial stability.
3. Credit History
Lenders review:
- Missed payments
- Defaults or CCJs
- Recent searches
- High utilisation
- Previous mortgage conduct
Bad credit does not automatically block the switch, but lender choice may narrow.
4. Your Own Residential Housing Plans
Lenders want to confirm:
- Where you will live
- Whether you need a new residential mortgage
- Whether the application forms part of a let-to-buy arrangement
Clear documentation helps avoid delays.
5. Deposit / Equity Position
Buy-to-let mortgages usually require:
- 25% deposit or 25% equity
- 30–35% for more complex cases
A higher equity level improves borrowing options and rates.
Switching to Buy to Let as Part of Let-to-Buy
A let-to-buy occurs when you:
- Remortgage your current home to buy-to-let
- Use equity to fund the deposit for your new residential purchase
This is a common route for movers who want to retain their existing home rather than sell it.
Property Requirements for Buy to Let Switching
Lenders often accept standard residential homes, but may be more selective with:
- HMOs
- Multi-unit blocks
- New-build flats
- Flats above commercial premises
- Non-standard construction
- Short-let or Airbnb-style rental plans
Specialist lenders may accommodate these scenarios with higher deposits.
How the Switch Works Step by Step
1. Check your current mortgage contract
- Are you still in a fixed rate?
- Are early repayment charges due?
- Does your lender allow consent to let?
2. Review your rental potential
You must confirm rental income through:
- A valuation
- Or a letting agent’s estimate, depending on lender rules
3. Assess your equity position
You may be able to release equity at the same time to support investment goals or help purchase a new home.
4. Submit the buy-to-let remortgage application
Expect to provide:
- Proof of income
- Bank statements
- ID and address verification
- Existing tenancy plans (if applicable)
5. Valuation & underwriting
The valuer will confirm the rental estimate.
The underwriter checks affordability, credit history and property suitability.
6. Mortgage offer & completion
Once approved, your residential mortgage switches to a buy-to-let product and you can legally let the property.
Common Scenarios When Switching Works Well
Scenario 1: Moving but Keeping the Property
You want to move home but retain your existing property as an investment.
Scenario 2: Increasing Property Values
Your home has increased in value, allowing a switch with equity release.
Scenario 3: Career Relocation
You need to move temporarily but want to return in future.
Scenario 4: Starting a Portfolio
Switching your first property can create the foundation for future buy-to-let investments.
Scenario 5: Negative Equity Recovery (Case-by-Case)
Some landlords use letting as a bridge until property values recover.
How to Strengthen Your Application
(General Information Only)
1. Maintain clean financial conduct
- Avoid unarranged overdrafts
- Ensure all payments are up to date
2. Reduce credit utilisation
Lower balances help demonstrate stability.
3. Secure a realistic rental estimate
Ensure rental income comfortably meets ICR rules.
4. Avoid new credit searches before applying
Multiple recent searches can reduce lender confidence.
5. Gather up-to-date documentation
Having paperwork ready speeds up approval.
Summary
Switching to a buy-to-let mortgage is a straightforward route for homeowners who want to rent out their property long term. The right approach depends on:
- Your rental plans
- Your lender’s rules
- Your equity position
- Whether you are also buying a new home
- Your credit and financial stability
With strong preparation, the switch can open valuable opportunities for long-term property investment.
This article provides general information only. For personalised support, regulated mortgage advice is required.
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Important information: Mortgage Bridge provides information only and acts as a mortgage introducer. We do not provide mortgage advice or make lender recommendations. We can introduce you to an FCA-regulated mortgage adviser who can provide personalised mortgage advice.