An HMO mortgage is a specialist buy-to-let mortgage for a House in Multiple Occupation — broadly, a property let to three or more tenants from two or more households who share facilities such as a kitchen or bathroom. Two things make HMO investment in London more involved than a standard buy-to-let. Lenders apply tighter criteria, often expecting larger deposits, landlord experience, and rental income that comfortably covers the loan. And the regulatory framework is among the most demanding in the country, combining Article 4 planning controls with mandatory HMO licensing and, in many boroughs, additional or selective licensing. Getting lender selection, planning, and licensing right from the outset is what keeps an HMO purchase on track.
This guide explains how lenders approach HMO mortgages in London, what the London regulatory framework means in practice, and what to prepare before you apply. It is written for prospective and existing HMO landlords, including those buying through limited companies, expanding portfolios, or converting a single dwelling to HMO use. For an overview of our London mortgage services, visit our London team.
HMO Mortgages at a Glance
An HMO is a House in Multiple Occupation. The basic definition is a property rented to three or more people forming two or more households who share facilities, although licensing categories apply different thresholds. HMO mortgages often require larger deposits than standard buy-to-let and a tighter affordability assessment. The exact figures vary by lender, property type, HMO size, landlord experience, and borrower structure, so any range should be treated as indicative rather than fixed. Some lenders will only consider HMO applications from landlords with prior buy-to-let experience. Many HMO investors hold properties through limited companies, but the right structure depends on tax, ownership plans, lender criteria, and long-term strategy, and should be discussed with a qualified tax adviser. In London, the regulatory position — Article 4 planning controls and HMO licensing — should always be checked with the relevant borough before you commit to a purchase.
Who This Guide Is For
Existing HMO landlords. Refinancing or expanding portfolios across London, or moving capital between boroughs.
First-time HMO investors. Moving from standard buy-to-let into multi-let property, where lender criteria and licensing are more demanding.
Conversion buyers. Buying a single dwelling to convert to HMO use, where Article 4 planning is usually the first hurdle.
Limited company investors. Holding HMOs through a special purpose vehicle for tax or portfolio reasons.
How Lenders Assess HMO Mortgages
Lenders treat HMOs as a more specialist proposition than single-let buy-to-let, and the criteria reflect that. The main factors are as follows.
Deposit and Loan-to-Value
HMO mortgages often require a larger deposit than standard buy-to-let. The amount depends on the lender, the size and type of HMO, your experience, and whether you are borrowing personally or through a company. At London property values, a higher percentage deposit also means a larger absolute sum, which is worth factoring into your budget early. These requirements vary between lenders and can change over time, so a current view of the market matters.
Rental Income and Stress Testing
Lenders assess affordability primarily on the property’s rental income rather than your personal income, stress-testing the expected rent against the mortgage using an interest coverage ratio. HMOs can generate higher gross rent than a single let, which can help, but the required coverage and the stress rate vary by lender and by how the property is let. Lenders will usually want evidence of the achievable rent, and some assess HMO income more cautiously than single-let income.
Landlord Experience
Many HMO lenders prefer, and some require, prior buy-to-let or HMO experience. A first-time landlord moving straight into an HMO will usually have fewer lender options, though not none. A broker can identify lenders whose criteria suit your level of experience.
Property Type and Specification
Lenders also consider the property itself: the number of lettable rooms, room sizes, whether it meets HMO standards, and whether works are needed to bring it up to standard. A property that already operates as a licensed HMO is generally more straightforward than one that needs converting. Where significant works are required, short-term finance is sometimes used before refinancing onto an HMO mortgage once the property is licensed and let. For more on this, see our London bridging guide.
Limited Company and SPV Lending
Many HMO investors hold property through a limited company, often a special purpose vehicle. Lender criteria differ for company applications, and the choice between personal and company ownership has tax and long-term implications. This is a decision to take with a qualified tax adviser rather than on lender criteria alone. For landlords holding four or more mortgaged properties, portfolio landlord rules also apply — see our portfolio landlord guide.
The London Licensing Reality
London is unlike most of the country when it comes to HMOs, because three separate systems can apply to the same property: planning, licensing, and building regulations. They are administered by different parts of the council and are easy to confuse. Understanding all three before you buy is the single most important step for a London HMO.
Article 4 and planning. Nationally, changing a property from a single dwelling (use class C3) to a small HMO (C4) can be permitted development. Many London boroughs have adopted Article 4 Directions that remove this right, which means full planning permission is usually needed to create a new small HMO. Larger HMOs generally require planning permission regardless. Where a property is already in lawful HMO use, that established use is normally protected, but a new conversion is not. Article 4 coverage differs by borough and can change, so the position should be confirmed with the borough’s planning team before you commit.
Mandatory licensing. A mandatory HMO licence is required across all London boroughs for properties let to five or more people forming two or more households who share facilities. This is a national threshold and applies regardless of where in London the property is.
Additional licensing. Many London boroughs operate additional licensing schemes that extend licensing to smaller HMOs, often those let to three or four people. Some apply borough-wide and others to specific areas. These schemes are designated for a fixed period and vary considerably between boroughs, so each property should be checked individually.
Selective licensing. Some boroughs also operate selective licensing, which applies to most privately rented properties in designated areas, not only HMOs. If a property falls within both a licensing category and a selective licensing area, more than one licence can be required. The London-wide picture changes as schemes are introduced or renewed.
In practice, a single London HMO purchase can require planning permission, an HMO licence, a selective licence, and building regulations approval for fire safety works — separate applications across more than one council department. The relevant borough’s housing and planning teams can confirm the current position, and the London-wide licensing picture can be checked through the Greater London Authority’s property licence checker. Operating an HMO without a required licence is a criminal offence and can lead to significant financial penalties and rent repayment orders, so the licensing position should be settled before completion, not after.
Upfront Costs to Budget For
The cost of setting up or maintaining an HMO in London is often higher than for a single let. The main items to plan for are as follows.
Fire safety and conversion works. HMOs must meet specific fire safety standards, which can include interlinked alarms, fire doors, and adequate escape routes, alongside minimum room sizes and kitchen and bathroom provision. The exact standards are set by the borough and the property’s licence conditions.
Licence fees. Licence fees vary by borough and by the number of occupants or rooms, and are payable to the council rather than the lender. Some boroughs offer reduced fees for accredited landlords. Fees change over time, so current figures should be confirmed with the borough.
Professional and survey costs. Conversions and larger HMOs can involve architect, planning, and survey costs, and lenders may require a more detailed valuation. A fire risk assessment is also commonly needed, and some lenders ask to see one before releasing funds.
The Renters’ Rights Act and HMOs
The Renters’ Rights Act 2025 received Royal Assent on 27 October 2025, with implementation phased through 2026. As a substantial reform of the private rented sector in England, it changes how tenancies are managed, including for HMOs, with measures affecting how tenancies end and how rents are increased. The detail and timing of later phases remain subject to government implementation, so landlords should take current legal advice on how the Act affects their specific lettings. These changes do not directly affect your mortgage, but they do affect the management and risk profile of an HMO.
Practical Steps Before You Apply
Check the planning and licensing position first. Confirm with the borough whether Article 4 applies, what licence the property needs, and whether it sits in a selective licensing area. This shapes everything that follows.
Decide on ownership structure with advice. Whether you buy personally or through a limited company has tax and lending implications, and is best decided with a qualified tax adviser before you approach lenders.
Have your documentation ready. Evidence of rental income or projected rent, details of any existing portfolio, and company accounts if buying through an SPV all help the application move more quickly.
Factor in the works and the timeline. If the property needs converting or upgrading, plan for the cost and the time involved, including any short-term finance and the point at which you refinance onto an HMO mortgage.
Why We Wrote This Guide
Fitch & Fitch is an independent, whole-of-market mortgage broker with offices in Canary Wharf, Cambridge, and Colchester. We are an appointed representative of JLM Mortgage Network, authorised and regulated by the Financial Conduct Authority (FCA Registration Numbers 955014 and 300629). You can verify this on the FCA Register at register.fca.org.uk.
Fitch & Fitch has received recognition from independent industry bodies including the Mortgage Strategy Awards, Mortgage Introducer Awards, and Legal & General Mortgage Club Awards. These awards are judged independently and can be verified on the respective awards websites.
We wrote this guide because we believe an informed landlord makes better decisions. HMO investment in London sits at the intersection of mortgage lending, planning, and licensing, and many landlords also take advice from a qualified tax adviser and, for conversions, a planning specialist. For further information about our London mortgage services, visit our London hub page.
Frequently Asked Questions
What is an HMO mortgage?
An HMO mortgage is a specialist buy-to-let mortgage for a House in Multiple Occupation — a property let to multiple tenants from more than one household who share facilities. Lenders assess HMOs differently from single-let buy-to-let, usually with tighter criteria, and the property must meet HMO standards and any licensing requirements.
Can a first-time landlord get an HMO mortgage in London?
In some cases, yes, but the options are usually more limited. Many HMO lenders prefer applicants with prior buy-to-let experience, and some require it. A first-time landlord moving straight into an HMO will generally have fewer lenders to choose from. A broker can identify which lenders consider applicants at your level of experience.
Do I need planning permission for an HMO in London?
Often, yes. Many London boroughs have Article 4 Directions that remove permitted development rights for converting a single dwelling to a small HMO, which means full planning permission is usually required to create one. Larger HMOs generally need planning permission regardless. Article 4 coverage varies by borough and can change, so confirm the position with the borough’s planning team before committing.
Do I need an HMO licence in London?
Usually. A mandatory licence is required across all London boroughs for HMOs let to five or more people from two or more households. Many boroughs also operate additional licensing for smaller HMOs, and some operate selective licensing covering most private lets in designated areas. Schemes vary by borough and change over time, so the position should be checked with the relevant borough. The Greater London Authority’s property licence checker can help identify which schemes apply.
How much deposit do I need for an HMO mortgage?
HMO mortgages generally require a larger deposit than standard buy-to-let, but the amount depends on the lender, the size and type of HMO, your experience, and whether you borrow personally or through a company. At London property values, the deposit is a larger absolute sum than in lower-priced markets. A broker can give a realistic figure for your circumstances based on current lender criteria.
Should I buy an HMO through a limited company?
It depends. Many HMO investors use a limited company, often a special purpose vehicle, but the right structure depends on your tax position, ownership plans, and long-term strategy. Lender criteria also differ for company applications. This is a decision to take with a qualified tax adviser rather than on lending considerations alone.
What is the difference between a buy-to-let and an HMO mortgage?
A standard buy-to-let mortgage is for a property let to a single household. An HMO mortgage is for a property let to multiple households who share facilities. HMO lending usually involves tighter criteria, larger deposits, and additional requirements around licensing and property standards, and the pool of lenders is smaller. See our general buy-to-let guide.
Which London boroughs require an HMO licence?
Mandatory licensing applies in every London borough for larger HMOs. Beyond that, additional and selective licensing differ borough by borough — some apply schemes borough-wide and others to specific areas — and they change as schemes are introduced or renewed. Rather than relying on a general list, the position for a specific property should be confirmed with the relevant borough or through the Greater London Authority’s property licence checker.
Next Steps
If you are planning to buy or refinance an HMO in London, a useful first step can be confirming the planning and licensing position with the relevant borough and reviewing how the numbers work against current lender criteria. A broker who understands HMO lending can help you identify lenders whose criteria suit the property and your experience, and present the case clearly.
For further information about our London mortgage services, visit our London hub page.
Related Guides
Buy-to-Let Mortgages in London
Portfolio Landlord Mortgages in London
Complex Income Mortgages in London
Your property may be repossessed if you do not keep up repayments on a mortgage or any other debt secured on it.
The information above is for general guidance only and does not take account of your personal circumstances. Property values can go down as well as up, and rental income is not guaranteed. Tax and legal decisions regarding property ownership structure should be made with the advice of a qualified accountant and solicitor.