Permitted development conversions are a growing entry route for SME developers in 2026, and they can be funded with development finance. Changes to permitted development rights in March 2024 — removing Class MA's vacancy rule and floorspace limit — have widened the commercial-to-residential route without full planning consent, and have created a substantial pipeline of office blocks and retail units being brought into residential use. Many developers entering the market for the first time are doing so through permitted development rather than greenfield ground-up schemes.
But PD finance is not the same product as ground-up development finance. The absence of full planning consent risk is a genuine advantage; the risks it substitutes — structural unknowns, building regulations compliance costs, and thinner GDV evidence — are just as real to a lender, and they price and structure the loan accordingly. This guide explains how lenders view PD conversion projects, what finance is available at each planning stage, and how the numbers compare to a conventional full-planning scheme.
What is permitted development and why does it matter for finance?
Permitted development rights allow certain changes of use and conversions to proceed without full planning permission, subject to a Prior Approval process with the local planning authority. Prior Approval is not automatic: the LPA can refuse on specific grounds — flood risk, transport impact, noise, contamination, design in some cases — but the scope of refusal is narrower than under full planning, and the consent timeline is substantially shorter: six to eight weeks for Prior Approval versus thirteen to twenty-six weeks (or more) for a full planning application.
The PD classes most relevant to development finance are:
- Class MA — Use Class E (commercial, retail, light industrial) to residential. A widely used route for office and retail conversions, widened in March 2024, when the vacancy rule and floorspace limit were removed.
- Class O — office to residential. The predecessor to Class MA; largely superseded but some lenders and valuers still reference it for pre-2021 Prior Approvals.
- Class Q — agricultural buildings to residential. Covers barn conversions and rural agricultural structures; a growing niche following Labour's 2025 relaxations, but one where lender caution is notably higher.
- Class G — commercial to mixed-use; less commonly used for development finance purposes but relevant for schemes incorporating a retained commercial element.
For finance purposes, the critical distinction is between pre-Prior Approval and post-Prior Approval. Lenders treat these as materially different risk profiles — and they structure and price accordingly.
How lenders assess PD conversion projects
The underwriting logic for PD conversions follows the same framework as ground-up development finance — planning status, GDV evidence, cost plan, exit, and borrower track record — but the specific risks within each category are different.
Planning risk. Ground-up development finance starts from a position of confirmed planning consent. PD loans frequently do not. Pre-PA lenders are willing to advance funds before Prior Approval is confirmed, but they price that risk: typically a higher arrangement fee, a lower LTC, and a condition that the loan reverts to a bridging rate or falls away entirely if PA is refused. Post-PA lenders — the majority of mainstream development finance providers — will not credit-approve until Prior Approval is in hand. The practical implication: securing PA before approaching the bulk of the lender market unlocks materially better terms.
Structural and building regulations risk. An office block or retail unit bought under PD rights comes with structural unknowns that a cleared greenfield site does not. Asbestos in older commercial buildings, the cost of achieving fire separation between converted units, acoustic compliance under Part E of the Building Regulations, and Part L energy efficiency requirements can all add material cost to a conversion programme. Lenders require a building survey — typically a full structural survey, not just a homebuyer's report — before credit approval, and they want a cost plan that addresses the building regulations compliance programme explicitly. A cost plan built on schedule rates without a clear compliance route will not survive a monitoring surveyor's pre-loan review.
GDV evidence. Converted ex-commercial flats and purpose-built new-build flats do not always achieve the same price per square foot. In town centres with thin supply of quality residential accommodation, the gap can be small; in secondary locations, it can be significant. Lenders commission an independent RICS Red Book valuation; the valuer applies their own view of comparable evidence for converted units specifically, not new-build comparables. Bring your own comparable sales evidence for converted stock — not new-build — when you present to a lender, and address the conversion premium or discount directly.
Exit. The exit structure for PD conversions is the same as ground-up: sale of completed residential units, or refinance onto a buy-to-let or investment mortgage at completion. PD-converted stock refinances on the same criteria as any other residential property; the conversion origin does not affect the refinance lender's assessment, provided the building regulations compliance has been signed off correctly.
What LTC and LTGDV are available on PD conversions?
Post-Prior Approval, clean scheme with a confirmed cost plan and a structural survey with no material unknowns: LTC and LTGDV are broadly comparable to full-planning ground-up. Senior debt typically covers 65–70% LTC and 60–65% LTGDV, with a modest pricing premium over an equivalent ground-up scheme reflecting the conversion risk premium.
Pre-Prior Approval, or schemes where structural risk is not yet quantified: lenders reduce LTC to 55–65% and LTGDV to 55–60%, and the available panel narrows significantly. A small number of specialist lenders actively finance PD schemes at this stage; the majority will wait.
Class Q agricultural conversions attract the most caution: LTC typically 55–65%, LTGDV often 55–60%, and some lenders decline the product entirely. The structural variability of agricultural buildings — some are steel-frame portal structures with no masonry, which are close to unworkable for residential conversion without a rebuild — and the thin comparable evidence base in rural locations make underwriting harder.
Where senior debt alone leaves a gap between the available loan and the total project cost, a mezzanine finance layer can sit above senior debt to take total leverage to 85–90% of cost — the same senior-plus-mezz stack available on ground-up schemes, at a similar pricing structure. For developers with limited equity, the mezz route is available on the right PD scheme; the underwriting for the mezz layer is at least as rigorous as for ground-up, and structural unknowns make it harder to achieve on pre-PA or Class Q conversions.
Class MA in 2026 — what lenders look for
Class MA is the route most lenders are now familiar with for PD conversion finance. The March 2024 widening — removing the vacancy rule and the floorspace limit — has made it a main mechanism for town-centre office and retail conversions. Lender familiarity has improved, though not uniformly.
The specific underwriting considerations for Class MA that go beyond the standard PD checklist:
- Floor-plate efficiency. The ratio of usable residential net internal area (NIA) to total gross internal area (GIA) determines how much GDV the scheme generates per square foot of building. A deep-plan office floor plate with a central core and limited natural light perimeter may yield a poor conversion ratio — functional as office space, but inefficient as residential. Lenders look at this before the valuer commissions the Red Book; a scheme where only 60% of GIA converts to saleable NIA is a materially different proposition from one where the ratio is 80%.
- Amenity standards. PD Prior Approval does not guarantee that the scheme is financeable, only that it is legal. Minimum space standards (the nationally described space standards apply to PD conversions in many local authority areas), daylight and sunlight requirements, and the absence of any requirement for external amenity space can all affect what the completed units will achieve in the market — and therefore what GDV the valuer will support.
- Comparable sales evidence. Ex-office converted flats in a secondary town centre may sit meaningfully below comparable new-build in the same postcode. Assemble the evidence before you present to a lender; the gap between your GDV estimate and the valuer's certified figure has a direct and immediate impact on the maximum loan.
- PBSA is a different route. Class MA converts commercial space to ordinary homes (Use Class C3) only; purpose-built student accommodation normally needs full planning permission, so it does not sit within Class MA. Where a commercial building is being converted to student accommodation, the underwriting framework adds an operational layer (per-bed rental assumptions, sustainable occupancy, university covenant strength) on top of the standard PD conversion checklist. For a PBSA-specific treatment of the conversion economics and institutional forward-funding options, see our PBSA development finance page.
Costs — how PD finance is priced
As indicative ranges for 2026: post-Prior Approval senior development finance for a PD conversion scheme is typically priced at a modest premium to the typical senior rate of around 7.5% a year. Pre-Prior Approval schemes carry a further premium. These are indicative ranges only; specific pricing depends on the scheme, the LTC, the structural risk profile, and the lender relationship, and will sit outside these ranges in either direction on schemes at the edges of the credit spectrum.
Lender arrangement fees are typically 1–2% of the facility. The lender appoints an independent monitoring surveyor, paid for by you. The fee is generally £500 to £2,000, depending on the size of the scheme. Exit fees vary by lender and product; some lenders charge none.
Total finance cost over an eighteen-month conversion — rolled interest, arrangement fee, monitoring surveyor, structural surveys — should be modelled against your GDV before you fix a purchase price for the commercial property. The conversion cost risk and the finance cost together will determine whether the scheme's margin survives to profit.
PD versus full-planning ground-up — which is better?
The answer is scheme-specific. PD is not inherently better or worse for financing purposes; it is different, with a different risk profile and a different lender response.
PD advantages for finance: faster consent timeline (no planning risk if PA is granted); lower pre-commencement cost (planning consultants, EIA, public consultation); faster start on site once PA is confirmed.
PD disadvantages for finance: building regulations compliance costs can exceed those of a new-build scheme; GDV per square foot for converted stock is often lower than new-build in the same postcode; the lender panel is narrower; and PA can still be refused, creating an unrecovered cost if the project stalls at that stage.
Refurbishment finance — for light-to-medium conversion works on a property that retains its existing use — sits adjacent to PD finance but is a distinct product. The lines blur at change-of-use: a PD conversion that involves significant building works is treated as development finance, not refurbishment finance, once works exceed a lender's threshold for structural intervention.
For first-time developers, PD can be an accessible entry route — a smaller site, a shorter programme, and a simpler planning position than a full greenfield consented scheme. But the structural unknowns and the narrower lender panel mean that a first-time developer approaching a PD scheme needs even more rigorous preparation than for a standard ground-up project: building survey before you exchange, cost plan in place before you approach a lender, and Prior Approval confirmed before you expect competitive terms.
The right sequence — due diligence before finance
The most common error on PD conversion finance is approaching lenders before the building due diligence is complete. The sequence that works:
- Building survey. Commission a full structural survey before exchange. Identify asbestos, structural condition, and the scope of building regulations compliance works required. Without this, neither your cost plan nor your lender approach is credible.
- Cost plan. Build an itemised schedule of conversion works against the building survey findings, with contractor input and 10–15% contingency. The cost plan drives the LTC calculation and the monitoring surveyor's pre-loan review.
- Prior Approval confirmation. Confirm PA before approaching the main lender market. Pre-PA finance is available but expensive and from a narrow panel; post-PA opens up a materially wider market at better pricing.
- Lender approach. Present building survey, cost plan, PA confirmation, and comparable GDV evidence together. A well-prepared PD conversion — with known structural position, a confirmed consent, and evidenced GDV — is a fundable scheme.
What to do next
PD finance is available, and for the right scheme it is increasingly mainstream. The lender panel is narrower than for full-planning ground-up, the structural due diligence is more demanding, and the GDV evidence burden is higher — but a well-prepared Class MA or Class Q conversion with Prior Approval confirmed and a clean structural position will access competitive development finance.
For a worked example, see our Manchester permitted development conversion case study.
The capital structure decision — senior only, or senior plus mezzanine, or a JV equity arrangement — applies to PD conversions exactly as it does to ground-up. The leverage available is comparable on strong post-PA schemes; the structural risk profile determines how hard you can push it.
We arrange development finance for PD conversions as well as full-planning ground-up, and we produce the development appraisal and cashflow as part of the funding process. Tell us about your scheme and we'll tell you what structure it can support and at what price.