Developer finance for conversion projects in the UK is most commonly arranged through bridging loans for property conversion projects, which give developers and landlords fast access to capital to buy, refurbish or change the use of a building before refinancing onto a longer-term product or selling on completion. These loans are secured against the property itself, typically run for three to eighteen months, and are built around the project's exit rather than the borrower's income. For conversions, that flexibility is often the only route a mainstream lender simply won't offer.
Conversion projects sit in an awkward spot for traditional lenders. A barn that's about to become three cottages, or an office block heading for residential use under permitted development rights, doesn't fit neatly into a standard mortgage box. Banks want a finished, lettable or saleable asset before they'll lend sensibly against it. Developer finance exists precisely to bridge that gap between what a property is now and what it will become once the work is done.
In our experience at Boxx Finance, the brokers who deal with this type of lending day in, day out see the same pattern repeat itself across the country. A developer finds a tired, underused building, sees the potential, and then discovers that their existing bank account manager has no appetite whatsoever for lending against a half-finished conversion. That's not a reflection on the deal, it's simply that mainstream banks are built around standard residential and commercial products, not transitional assets. Specialist developer finance fills that gap deliberately.
It's also worth saying that conversion finance isn't a niche corner of the market anymore. With permitted development rights expanding in recent years to cover more commercial-to-residential changes of use, and with planning authorities increasingly supportive of bringing empty buildings back into use, demand for this type of lending has grown steadily. Lenders have responded by building dedicated conversion products, often with more flexible staged drawdown structures than were common even five years ago.
What this means in practice
In practice, developer finance for conversion work means borrowing against the current value of a property, sometimes with additional funds released in stages as the conversion progresses, so the project can be completed without the developer tying up all their own cash.
For a landlord converting a large Victorian house into flats, this might mean drawing an initial tranche to complete the purchase and the first phase of works, then calling down further funds as building control sign-offs are reached. For a developer taking on a disused commercial unit for office-to-residential conversion, it often means the lender assessing the gross development value on day one and lending a percentage of both the purchase price and the works cost.
The practical upshot is that the loan is structured around milestones, not a single lump sum. Lenders will usually appoint a monitoring surveyor who visits the site, confirms progress matches the drawdown schedule, and signs off each stage before money moves. This protects the lender, but it also protects the developer from overextending on a project that stalls.
One thing that catches first-time developers out is assuming the loan covers everything from day one. Most conversion bridging loans release the purchase funds and perhaps the first works tranche at completion, with the rest held back against progress. Cash flow planning around those drawdown gaps matters as much as the headline loan amount.
It's also worth being realistic about planning status. Lenders are far more comfortable funding a conversion where planning permission or permitted development rights are already confirmed, rather than speculative. If you're still waiting on consent, there are routes to fund that stage too, which is covered in more detail in a separate guide on funding projects while planning decisions are pending.
There's a practical rhythm to how staged drawdowns tend to work on a typical conversion. The first drawdown usually covers completion of the purchase and sometimes an initial works payment to get scaffolding up and strip-out started. Subsequent drawdowns, often three or four over the course of a nine to twelve month build, are released once the monitoring surveyor confirms specific stages, such as first fix completion, roof and envelope works finished, or second fix and internal finishes underway.
Each drawdown request typically takes the lender between three and ten working days to process once the surveyor's report is received, depending on how responsive the lender's underwriting team is and whether the report flags any concerns. Developers who build this lag into their cash flow planning rarely have problems. Those who assume money will land the same day they ask for it often find themselves paying contractors late, which damages relationships on site and can slow the whole build down.
Another practical point worth flagging is retention. Some lenders hold back a small retention from each drawdown, perhaps 5% to 10%, released only once the full facility is drawn and the final inspection confirms the works match what was costed. This is standard practice rather than a red flag, but it needs to be factored into the developer's own cash position so there are no surprises near the end of the project.
How it works
Developer finance for conversions works by the lender valuing the property on both its current basis and its projected end value, then lending against a blend of the two depending on the stage of the loan.
At the outset, a lender will typically assess the purchase price or current market value, the full schedule of works and costs, the gross development value once converted, and the experience of the developer. Loan to value on the day one purchase price commonly sits between 65% and 75%, with total loan to gross development value usually capped around 65% to 70% once works funding is included.
Rates for conversion bridging loans in the UK typically range from around 0.55% to 0.95% per month depending on the complexity of the scheme, the loan size, and the strength of the exit. Arrangement fees are usually 1.5% to 2% of the gross loan, and most lenders also charge an exit fee or require a minimum interest period, so it's worth checking the small print rather than assuming the headline rate is the full cost.
Beyond the headline rate and arrangement fee, there are a handful of other costs worth budgeting for properly. Valuation fees for a conversion project, particularly one requiring a projected gross development value assessment, often run from £600 up to £2,000 or more depending on the size and complexity of the scheme. Monitoring surveyor fees are usually charged per visit, typically £300 to £600 a time, and with four or five visits over the course of a build that adds up to a meaningful sum that developers sometimes forget to include in their overall cost projections.
Legal fees are another area where first-time developers underestimate the true cost. Expect to pay both your own solicitor's fees and a contribution towards the lender's legal costs, which together might run from £1,500 to £3,500 on a typical conversion deal, more if the title is complex or there are multiple units being created that need separate leasehold or freehold arrangements set up during the build.
The application process generally runs like this: initial terms are issued within a day or two of enquiry based on the figures provided, a valuation and monitoring surveyor are instructed, legal work runs in parallel, and funds are released once searches, title and the facility agreement are all in place. For a straightforward conversion with planning already granted, completion in three to five weeks is realistic. More complex schemes, or ones involving multiple units or leasehold title, often take six to eight weeks.
Developers who want staged drawdowns need to be clear with their lender from the outset about the build programme. Lenders rarely say this outright, but a messy or unrealistic build schedule submitted at application stage is one of the fastest ways to get a worse rate offered, or the facility declined entirely, because it signals the developer hasn't properly costed the job.
A well-prepared application tends to include a few specific documents that experienced developers learn to have ready from the outset. A detailed schedule of works broken down by trade and stage, a fixed-price or near fixed-price build contract where possible, evidence of planning consent or permitted development confirmation, and a clear statement of the proposed exit route all help speed the process along considerably. Applications missing these elements tend to sit in underwriting longer while the lender chases for more information.
If you're weighing up whether a bridging loan or a different structure suits your scheme, it helps to talk it through. You can compare bridging loan options for your conversion before committing to a particular lender or structure.
Typical scenarios
The scenario below is illustrative, a composite example reflecting the shape of deals of this kind, not a specific, identifiable transaction. Consider a landlord in Horsham who owns a redundant agricultural barn with planning consent already granted for conversion into two three-bedroom dwellings. The purchase price (she already owns the site, so this reflects current market value) is £310,000, and the build cost is estimated at £180,000 across a nine-month programme. The projected gross development value on completion is £650,000.
A lender agrees a facility of £360,000, made up of £220,000 released at completion against the existing value of the barn and £140,000 released in four staged drawdowns tied to monitoring surveyor sign-offs as the works progress. This represents roughly 71% loan to current value and around 55% loan to gross development value, comfortably within typical lender appetite. The rate agreed is 0.75% per month with a 2% arrangement fee, and the facility runs for twelve months with no early repayment charge after month six.
The exit is a straightforward one: once both units are complete and building control sign-off is obtained, the landlord refinances onto a buy-to-let mortgage against each unit, using the rental income from both to support the new lending, and repays the bridging facility in full. From initial enquiry to first drawdown, the whole process takes around five weeks, with the full build and staged drawdowns running over the following nine months.
This kind of deal is a good illustration of why developer finance suits conversions so well. A high street lender wouldn't touch the barn in its current state, and a standard commercial mortgage wouldn't fund works costs in stages. The bridging structure matches money to progress, and the refinance exit is realistic because two finished rental units generate a clear, assessable income.
It's worth looking at a second, slightly different scenario to illustrate how the numbers shift with a commercial-to-residential conversion. A developer in Reading identifies a vacant two-storey office building suitable for conversion into six one-bedroom flats under permitted development rights. The purchase price is £480,000, the works budget comes in at £390,000 once professional fees and contingency are included, and the projected gross development value across the six units is £1,320,000.
Here the lender structures a facility of £858,000 in total, with £336,000 released at completion representing 70% of the purchase price, and the remaining £522,000 released across six drawdown stages matched to the build programme. The blended loan to gross development value sits at 65%, at the upper end of what most specialist lenders would consider for a scheme of this size, reflecting the developer's track record of having completed two similar projects previously.
The rate on this larger, more complex facility comes in slightly higher at 0.85% per month given the scale and the multi-unit nature of the exit, with a 2% arrangement fee and an eighteen month term to allow margin for any delays in the build or the sales process. The exit here is a sale of all six units individually, with the developer having already instructed a local agent to produce comparable evidence supporting the projected values before the facility even completed.
What lenders look for
Lenders assess conversion developer finance primarily on the strength of the exit, the experience of the developer, and the quality of the security, in that order of importance for most specialist lenders.
On loan to value, expect a range of 65% to 75% against day one value for straightforward residential conversions, dropping to around 55% to 65% loan to gross development value where significant works funding is included. Conversions involving listed buildings, complex planning conditions, or unusual construction methods tend to sit at the lower end of these ranges, or require a specialist lender with specific experience in that asset class.
Security needs to be a legal charge over the property, usually first charge, though second charge facilities are available from some lenders where there's sufficient equity and the first charge lender consents. Lenders will want full title information, an up-to-date valuation from a RICS surveyor, and in most cases a monitoring surveyor appointed for the duration of the build.
On the exit, lenders want evidence it's genuinely achievable, not just asserted. For a sale exit, that means comparable evidence of demand and pricing in the local market. For a refinance exit, that means a realistic assessment of whether the finished asset will qualify for a mortgage, often supported by an agreement in principle from the refinance lender before the bridging facility even completes.
Developer experience is weighted more heavily than many first-time applicants expect. Lenders will typically ask for a CV-style summary of previous projects, including the type of work, the value, and how it was funded and exited. A developer with three completed conversions behind them will often access better rates and higher loan to value than someone attempting their first, even where the current project itself looks identical on paper.
Lenders also look closely at the professional team around the project. A named project manager, a contractor with a track record on similar schemes, and an architect or planning consultant who has already navigated the relevant consent process all add credibility. Where a developer is managing the build themselves without any of this support, lenders tend to either decline or require a lower loan to value to offset the perceived risk.
| Loan type | Typical LTV | Typical monthly rate |
|---|---|---|
| Purchase only, light refurbishment | 70-75% | 0.55-0.70% |
| Conversion with staged works funding | 60-70% of GDV | 0.65-0.85% |
| Heavy conversion, complex planning | 50-60% of GDV | 0.80-0.95% |
The most common reason applications like this get declined isn't the headline loan to value at all, it's an unrealistic build cost schedule or a developer with no demonstrable track record attempting a scheme that's bigger or more complex than anything they've completed before. Lenders will often still fund a first-time developer, but usually at a lower loan to value, with a stronger emphasis on a fixed-price build contract and an experienced project manager named on the application.
It's also worth noting that lenders differentiate between types of conversion in terms of perceived risk. A residential-to-residential conversion, such as splitting a large house into flats, is generally viewed as lower risk than a commercial-to-residential change of use, simply because the latter can involve more unknowns around structural condition, services, and compliance with residential building regulations that commercial buildings were never designed to meet.
Similarly, conversions of listed buildings or those in conservation areas attract extra scrutiny because planning conditions can be more restrictive and unexpected costs more likely once work begins. Lenders aren't averse to funding these schemes, but expect more detailed due diligence and potentially longer timescales to get to an offer. Developers based near Newark, Worthing or Blackpool will find the same principles apply regardless of location, though local market conditions can influence the lender's view of the exit.
Common mistakes
The most frequent mistake is underestimating build costs and contingency, which then causes a drawdown shortfall halfway through the project when the loan simply doesn't stretch far enough to finish the job.
A sensible contingency is 10% to 15% of build cost, built into the facility from the start rather than assumed to be available later. Lenders would much rather see a realistic budget with contingency included than an optimistic one that leaves no room for the unexpected, and conversions in particular throw up surprises once walls come down and original structures are exposed.
Another common error is assuming planning consent alone is enough to secure funding without having thought through building control and party wall matters, especially on conversions involving shared structures or multiple units. Lenders will ask about this, and a developer who can't answer confidently raises doubt about the whole application.
Developers also sometimes choose the cheapest headline rate without checking exit fees, minimum interest periods, or whether the lender will genuinely release staged drawdowns promptly once monitoring surveyor reports come in. A facility that's 0.1% cheaper per month but releases drawdowns two weeks late every time can cost far more in delayed build programmes than it saves in interest.
Finally, leaving refinance planning until the build is nearly finished is a mistake that causes real problems. Mortgage lenders for finished conversions sometimes have minimum ownership periods, valuation quirks around new-build warranties, or restrictions on recently converted properties. Speaking to a refinance lender early, ideally before the bridging facility even completes, avoids an awkward scramble at the end of the project.
A less obvious but equally damaging mistake is underestimating how long building control sign-off can take once works are physically complete. Developers sometimes assume that finishing the last fix and snagging means the project is done, only to find building control inspections and the final completion certificate take a further few weeks. This matters because many refinance lenders and buyers want to see that certificate before they'll proceed, which can leave a developer paying bridging interest for longer than planned.
Another pitfall worth mentioning is failing to notify the lender promptly when the build programme changes. If a contractor falls behind, or an unexpected structural issue is found once walls are opened up, most lenders would much rather hear about it early and discuss a revised drawdown schedule than discover it during a routine monitoring surveyor visit. Lenders generally respond well to proactive communication and poorly to surprises.
Alternatives or comparisons
Developer finance for conversions is the wrong choice if the project doesn't need speed or staged funding and a standard commercial mortgage or self-build mortgage would do the job more cheaply.
If you're converting a single property you intend to live in yourself, with a straightforward build timeline and no urgency on purchase, a self-build mortgage releasing funds in stages against an agreed valuation schedule will usually be cheaper over the life of the project, even if the application process is slower. Bridging loans earn their cost through speed and flexibility, and if you don't need either, you're paying for something you're not using.
Equally, if the conversion is small in scale, such as converting a single garage into habitable space, and the cost can realistically be covered by unsecured business finance or savings, taking out a secured loan against the whole property is disproportionate. Keep the funding structure proportionate to the project.
Where a conversion is genuinely speculative, with no planning permission at all and significant uncertainty over whether consent will be granted, a straight bridging loan against the undeveloped asset may still work, but expect a lower loan to value and a lender who's comfortable with that level of risk, which narrows the field considerably. The companion guide on short-term funding while awaiting planning decisions covers this specific situation in more depth.
For larger conversion schemes, some developers consider a joint venture or equity partnership rather than debt finance, bringing in a funding partner who takes a share of profit rather than charging interest. This can suit developers with limited capital of their own, though it means giving up a portion of the upside, and it's a different conversation entirely to arranging a bridging facility.
Commercial mortgages are worth considering where the conversion is complete and income-producing already, perhaps where a developer has bought a building with existing tenants in situ and the conversion work is minor compared to the overall value. In these cases, a term loan from day one, rather than a short-term bridge followed by a refinance, might avoid two sets of arrangement fees and legal costs.
For first-time developers wondering whether they're even ready to take on a conversion project with borrowed funds, it's worth reading a dedicated guide to bridging loans for first-time property developers before approaching lenders, since preparation at this stage materially affects the terms on offer. Those tackling an agricultural building specifically may also find it useful to read about barn conversion funding requirements before finalising their build budget.
How to get the best outcome
The best outcome comes from treating the application like a business case, with a realistic build budget, a credible exit, and a broker who places conversion deals with specialist lenders regularly, rather than approaching generalist lenders who dabble in bridging occasionally.
Get a proper build cost breakdown from a quantity surveyor or experienced contractor before approaching lenders, not a rough estimate. Lenders scrutinise this closely, and a professionally prepared schedule of works signals a developer who's serious and organised, which tends to translate into better terms.
Have your exit strategy agreed in principle before you apply for the bridging facility itself. If the exit is a refinance, speak to that lender first. If it's a sale, have an estate agent's assessment of likely sale price and timescale ready to show. Lenders fund the exit as much as the asset, and a vague answer to a direct question about how the loan will be repaid is one of the quickest ways to stall an otherwise strong application.
It also pays to shop the deal properly rather than accepting the first offer that comes in. Rates, fees and drawdown processes vary significantly between specialist lenders, and a broker with genuine access to the whole market can often find a facility that's meaningfully cheaper or more flexible than whatever a single lender initially quotes. This is particularly true for conversion deals, where appetite varies widely depending on the lender's current exposure to that type of project and location.
Finally, build a realistic buffer into your own planning, both financially and in terms of timescale. Conversions rarely run exactly to the original programme, and a developer who has allowed for a month or two of slippage, along with a sensible contingency fund, tends to navigate the inevitable bumps far more smoothly than one who has budgeted to the absolute minimum. Getting the structure right at the outset, with the right lender, the right facility size, and a clear-eyed view of the risks, makes the difference between a conversion that runs smoothly and one that becomes a constant source of stress. If you'd like to discuss your scheme, you can get a bridging loan quote, or explore our wider range of property development funding options.
