Converting a house into an HMO: a finance guide

A good HMO conversion starts with the right building, and the best candidates share a few features. You are usually looking for a house with enough rooms, or enough space to create them, in a location with genuine demand for shared housing, such as near a university, a hospital, a large employer or a town centre with good transport. Layout matters as much as size: a property that converts to several sensible double bedrooms with room for shared kitchen and bathroom facilities works far better than one where the space fights you.

Demand is the anchor. An HMO only performs if the rooms let and stay let, so understanding the local tenant market, the typical room rent, and who you would be letting to is central before you offer. A property that looks cheap per square foot is no bargain if the rooms sit empty.

At the sourcing stage you should already be thinking about the two hurdles the next section covers, planning and licensing, because they can rule a property in or out. It is far cheaper to walk away from an unsuitable building than to buy it and discover the constraints afterwards. Line up your finance in principle at this stage too, so you can move quickly and buy with confidence when the right property appears.

Before you commit, you need to understand the planning position, because it determines whether you can lawfully create the HMO you are pricing for. Two things drive this: the use class and any Article 4 direction.

A normal family home sits in use class C3. A small HMO of roughly three to six unrelated occupants sits in class C4. In much of the country you can change from C3 to C4 under permitted development without a full planning application. But where a council has made an Article 4 direction, that permitted development right is removed, and the same conversion needs full planning permission, which the council can refuse. A larger HMO, generally seven or more occupants, falls outside C4 into a category the planners treat as sui generis, and that always needs planning permission regardless of Article 4.

So the checks are: confirm the current use class, check whether the property sits inside an Article 4 area, read the council's HMO policy for any density or spacing thresholds, and work out the size of HMO you actually intend to create. If planning permission is needed, treat it as a condition of the deal, not an afterthought. Where the position is unclear, take advice from a local planning consultant and confirm the detail with the local authority. Getting this wrong is the most expensive mistake in the whole process.

Once planning is understood, the physical conversion is where most of the budget goes. The aim is a property that meets the HMO licensing standards and is genuinely lettable to the tenants you are targeting, not just a house with extra beds squeezed in.

• Layout and room sizes: creating bedrooms that meet the minimum floor areas, and reconfiguring space to add rooms where the layout allows, without dropping below the standards.
• Fire safety: often the biggest single element, covering alarms and detection, fire doors, and protected escape routes, which is a core licensing requirement and not somewhere to cut corners.
• Amenities: enough kitchens, bathrooms and toilets for the number of occupants, since undersupplied facilities fail the standards and frustrate tenants.
• Finish and durability: a specification that stands up to shared use, because HMOs take more wear than a single-family let and cheap finishes cost more over time.

Build a realistic works budget with a contingency, and a realistic timeline, because both feed directly into your finance. Bridging is priced monthly, so an overrun costs real money, and the refinance cannot happen until the works are complete and the property is lettable. Get proper quotes, and take professional advice on fire safety and building compliance, before you fix your numbers or draw down funding.

An HMO lives or dies on its numbers, and the maths is different from a single let. Your gross income is driven by rooms multiplied by room rent, so a five-bedroom HMO at a given room rent produces far more than the same house let to one family. That is the whole appeal, and it is why HMO landlords can pay above ordinary residential value for the right building.

But look past the gross figure to the net. HMOs carry higher running costs than a family let: bills are often included, there is more management, higher wear, more frequent voids on individual rooms, and licensing and compliance costs. A sensible appraisal starts from gross room income, then deducts a realistic allowance for voids and bad debt, bills, management, maintenance and compliance, to reach a net figure. Judge the deal on net yield, not the headline gross, because the gross flatters every HMO and the net is what you actually keep.

The numbers also have to satisfy a lender. A term HMO mortgage is stress tested on rental cover, with interest cover ratios typically in the region of 125% to 145% depending on your tax position, and leverage up to roughly 70% to 75% of value, all subject to status and valuation. If the net income does not comfortably clear those tests, the property will not support the borrowing you are assuming, so it is far better to model this honestly at appraisal than to discover it at refinance. Nothing here is financial or tax advice, and you should take your own advice on the figures.

The reason conversions are usually funded in two stages is that no single product fits the whole journey. A property mid-conversion is not yet a lawful, licensed, income-producing HMO, so a term HMO mortgage is premature. A finished, licensed, let HMO no longer needs expensive short-term money. So the sensible structure moves through both.

Stage one, the bridge. A short-term bridging facility buys the property and funds the works. Bridging is comfortable with a property in transition and with a refurbishment plan, which a term lender is not. Indicative HMO bridging runs around 0.75% to 1.1% per month, with interest often rolled up so you are not servicing it monthly while the property produces no income. The bridge is sized around the purchase and the works, and it runs for the months you need to finish, license and let.

Stage two, the refinance. Once the HMO is complete, licensed and tenanted, you refinance onto a term HMO mortgage. Indicative HMO mortgage rates are around 5.5% to 6.5%, with leverage up to roughly 70% to 75% of the finished value and the rental stress tests noted above. If the conversion has genuinely added value, the refinance can release much of your original equity to recycle into the next project, which is how landlords build an HMO portfolio. All figures are indicative, subject to status and valuation. Structuring the bridge and the exit together from the outset, rather than bolting the mortgage on later, is what keeps a conversion on track.

Most conversions that go wrong go wrong in predictable ways, and knowing the pattern is the best protection.

• Assuming permitted development: buying at HMO value on the assumption you can convert under permitted development, then finding an Article 4 direction requires full planning you may not get. Check before you offer.
• Underbudgeting the works: especially fire safety, which is frequently the largest and most underestimated cost. An overrun on a monthly bridge is expensive.
• Trusting the gross yield: letting the headline room income hide the real running costs of an HMO, so the net return disappoints and the mortgage stress tests are missed.
• Leaving licensing late: not confirming mandatory, additional or selective licensing early, then facing delays or works that push back the refinance.
• Mismatched finance: using the wrong product for the stage, or failing to plan the bridge-to-mortgage exit, so the short-term money runs on longer and costs more than it should.

The thread through all of these is planning the deal properly before you commit: confirm planning and licensing, budget the works honestly with a contingency, appraise on net not gross, and line up finance that matches each stage with a clear exit. Do that and a conversion is a well-understood, repeatable project. As brokers we help structure the funding around the real position, though we do not give planning, legal or tax advice, and we would always encourage proper professional advice. HMO and commercial lending to companies and portfolio investors sits outside the FCA's consumer perimeter, while any regulated borrowing is referred to an authorised firm.