Can You Convert Your Residential Mortgage Into a Buy to Let?

Can You Convert Your Residential Mortgage Into a Buy to Let?

Many homeowners reach a point where their property is no longer used as their main residence but remains an asset they want to keep. Instead of selling, some consider letting it out. But can you simply convert your residential mortgage into a buy-to-let mortgage? The answer depends on your lender, the type of mortgage you currently hold and your future plans.

This guide explains how lenders assess applications to convert your residential mortgage into a buy to let, what conditions must be met and the options available when you want to start renting out a home you previously lived in. This article provides general information only and does not offer regulated mortgage advice.

Can You Convert a Residential Mortgage Into a Buy to Let?

Yes — but you cannot start letting the property without lender permission.
Your options usually fall into two categories:

  1. Consent to Let (temporary arrangement)
  2. Full Buy-to-Let Remortgage (permanent structure)

The right approach depends on how long you plan to let the property and the lender’s criteria.

What Is “Consent to Let”?

Consent to Let is when your current residential lender agrees to you renting out the property without switching the entire mortgage product. It is usually:

  • A short-term arrangement
  • Subject to additional fees or a different interest rate
  • Not designed for long-term rental plans

Lenders typically offer this when:

  • You are temporarily relocating
  • You plan to move back later
  • You are waiting to sell the property
  • Life circumstances require flexibility

Consent to Let is useful for short-term letting, but not considered a permanent solution.

When Do You Need a Full Buy-to-Let Remortgage?

A full remortgage into a buy-to-let product is necessary when:

  • You plan to let the property long term
  • Your lender does not offer Consent to Let
  • You want access to specific buy-to-let products
  • You plan to release equity for another purchase
  • Your residential lender declines your request

A buy-to-let mortgage is structured around rental income rather than personal income, though some lenders apply additional criteria.

What Lenders Look For When Switching to Buy to Let

1. Rental Income Coverage (ICR)

Lenders estimate expected rental income to assess whether the rent covers the mortgage payments under their stress test rules.
Typically, lenders require rental income to cover:

  • 125%–145% of the mortgage payment,
  • Stressed at an assumed interest rate (often 5.0–7.0% depending on lender and product).

2. Property Suitability for Rental Use

Lenders consider whether the property is appropriate for letting, including:

  • EPC rating (usually E or higher unless exemptions apply)
  • Condition and maintenance
  • Any structural concerns
  • Leasehold restrictions (if applicable)

3. Your Personal Circumstances

Although buy-to-let mortgages rely mainly on rental income, lenders may also assess:

  • Credit history
  • Existing borrowing levels
  • Previous mortgage payment conduct
  • Current residential stability
  • Overall financial position

4. Your Ownership Structure

Some lenders only allow buy-to-let borrowing in:

  • Personal name
  • Limited company
  • SPV (Special Purpose Vehicle) structure

The requirements differ by lender and product type.

5. Equity in the Property

Loan-to-value (LTV) limits for buy-to-let mortgages are typically:

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  • Maximum 75% LTV for most lenders
  • Lower LTVs may secure better rates

If your existing residential mortgage is higher than 75% LTV, reducing the balance may be required before switching.

Do You Need to Live in the Property First?

Most residential mortgages require you to have lived in the property before applying for Consent to Let or conversion. Exceptions include:

  • Accidental landlords
  • Inherited properties
  • Owners who never took occupancy due to sudden life changes

Each lender has its own rules.

What Happens to Your Current Mortgage Product?

When switching to buy-to-let, your residential mortgage product may:

  • Need to be replaced entirely
  • Trigger early repayment charges (ERCs)
  • Require the lender’s approval before changes
  • Convert into a specialist buy-to-let product with different terms

Timing the switch around ERC end dates is common.

Fees and Costs to Consider

When you convert to a buy-to-let mortgage, potential costs include:

  • Product fees for buy-to-let remortgage
  • Valuation fees
  • Legal fees
  • Consent to Let charges
  • Higher-rate interest products
  • Early repayment charges (if applicable)

Understanding these costs can help you plan the timing of the switch.

Common Scenarios and How Lenders Respond

Scenario 1: Temporary relocation abroad

Lenders often offer Consent to Let for 6–24 months.

Scenario 2: Moving in with a partner and renting out your old home

Likely requires either Consent to Let or a buy-to-let remortgage.

Scenario 3: Property in high equity position with strong rental income

Many lenders will consider a full buy-to-let remortgage.

Scenario 4: Borrower with recent credit issues wanting to switch to buy to let

Some lenders allow this, but options may be restricted.

Scenario 5: Home in negative or low equity

A full buy-to-let remortgage may be difficult due to LTV requirements.

How to Strengthen an Application to Convert to Buy to Let

(General Information Only)

Borrowers often improve approval chances by:

1. Ensuring rental income covers the lender’s affordability threshold

A letting agent’s rental estimate can support this.

2. Maintaining strong mortgage payment history

Lenders look closely at repayment conduct.

3. Reducing outstanding mortgage balance

Lower LTV = more lender options.

4. Keeping credit files clean and accurate

Even for buy-to-let, poor credit can limit options.

5. Ensuring the property meets EPC standards

Regulations continue to tighten.

6. Having an experienced letting agent prepare rental comparables

Lenders value independent rental valuations.

These steps are general considerations only.

What If Your Lender Declines the Switch?

If your current lender declines your request, you may:

  • Apply for a buy-to-let remortgage with another lender
  • Use a specialist lender if criteria differ
  • Stay on Consent to Let (if available)
  • Wait until criteria can be met (e.g., LTV reduction or market rent increase)

Lender policies vary widely, so a decline from one does not close all options.

Summary

You can generally convert your residential mortgage into a buy to let, but lenders must assess:

  • Rental income
  • Property condition
  • Borrower circumstances
  • Loan-to-value ratio
  • Whether plans are short-term (Consent to Let) or long-term (full buy-to-let remortgage)

Many homeowners successfully switch each year, whether temporarily or permanently.

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.