Permitted development finance for extensions and conversions

Vortex Finance is a whole-of-market property finance broker, not a lender. We do not fund the works ourselves; we compare a panel of 100+ lenders, find the one whose criteria fit your scheme, and package the case so it completes. There is no fee to get indicative terms. One thing we are clear about from the start: we arrange the money, but we do not confirm planning. Your permitted development rights should always be checked with a planning consultant or the local authority before you commit to a purchase or a works budget.

What permitted development actually means

Permitted development rights come from the General Permitted Development Order, usually shortened to the GPDO. They are a national grant of planning permission for certain works, which means you can carry them out without submitting a full planning application — provided you stay inside the limits and conditions the order sets.

That last part matters. Permitted development is not a free pass. Each right has its own size limits, height restrictions and conditions, and many require you to apply to the council for prior approval before you begin. Going beyond the limits, or skipping a required prior approval, turns lawful works into a planning breach. So the rights are useful, but they are conditional, and the detail is where projects succeed or stall.

Common permitted development projects

Most permitted development work falls into a handful of familiar categories, each of which can be funded:

The first four add value to a property you already own or are buying. The fifth, Class MA, is where some of the most interesting numbers sit, so it is worth its own section.

Class MA: turning commercial into residential

Class MA permits the change of use from commercial premises in Use Class E — which covers shops, offices, cafes and many other uses — into residential dwellings, without a full planning application. For investors, it can unlock cheap commercial floorspace and convert it into homes worth considerably more.

It is conditional, though. Since 5 March 2024 Class MA no longer imposes a floorspace cap on the area that can be converted, nor a minimum period during which the building must have been vacant beforehand — but it still requires prior approval covering matters such as flooding risk, noise, contamination and adequate natural light. A planning consultant will confirm whether your building qualifies; our job is to arrange the finance for the purchase and the conversion works once it does.

Why prior approval and a Lawful Development Certificate still matter

Two pieces of paper come up again and again on permitted development schemes, and both affect how cleanly your finance and your exit run.

Prior approval is the council’s sign-off on specific matters before you start. Many permitted development rights, including Class MA, are conditional on it. Skip a required prior approval and the works are not lawful, however straightforward the conversion looks.

A Lawful Development Certificate is not compulsory, but a lot of owners obtain one. It is a formal confirmation from the council that your works are lawful permitted development. That certainty is valuable: it removes the risk of an enforcement question later, it reassures a lender weighing the case, and it makes the finished property easier to sell or remortgage. One more area can remove your rights entirely — an Article 4 direction, which a council can use to withdraw specific permitted development rights in a defined area such as a conservation zone. Always check whether one applies before you bank on PD rights.

How to finance permitted development works

A standard mortgage will not help here, because it pays out a single lump sum against a finished home, not staged funds for a building site. Permitted development projects are funded one of three ways, and we match the structure to the scheme.

Refurbishment bridging suits lighter extensions and conversions that do not change the building’s footprint dramatically. Development finance suits heavier schemes, including Class MA conversions, releasing money in staged drawdowns as the works hit agreed milestones. A further advance or second charge can release equity from a property you already own to fund the works without disturbing a low-rate existing mortgage. In each case the facility is normally interest-only, with interest rolled up so there is nothing to service month to month, and it is repaid when you sell the finished property or refinance onto a longer-term mortgage.

Here is a worked example. You buy a vacant Class E office for £280,000 and plan a Class MA conversion into three flats, with works budgeted at £150,000, taking the all-in cost to around £430,000 before fees. The finished block has an expected end value of roughly £600,000. A development facility could fund a large share of the purchase plus the build cost in staged drawdowns — indicative gearing typically runs up to around 70% of cost — with interest rolled up and the whole facility cleared either by selling the flats or refinancing them onto buy-to-let mortgages. We map that structure before you commit, so you know the cash you need to put in and how the exit clears the loan.

Common questions

Related reading: our refurbishment finance hub explains light and heavy refurb funding in full, development finance covers staged-drawdown facilities for larger conversions, bridging loans set out short-term options, and commercial mortgages can take out a finished Class MA scheme that you keep rather than sell.

All rates, loan-to-values, gearing and timescales above are indicative as at June 2026 and confirmed by the lender on application. Vortex Finance arranges the finance and is a broker, not a lender. We do not provide planning advice — confirm your permitted development rights, prior approval and any Article 4 direction with a qualified planning consultant or your local authority.