What Does Planning Actually Cost For A Large HMO?
( 3 Min Read )
If you are converting a single family home into a Sui Generis HMO with 7 or 8 bedrooms, the council fee is just the beginning. Here is every cost you need to account for before you start.
One of the most common surprises for property investors venturing into large HMO development is the gap between the statutory planning fee and the true cost of getting a planning application over the line. By the time you have commissioned the right professionals and covered all the required reports, the bill looks very different.
This guide breaks down every line item so you can budget accurately from day one.
Measured Survey
Before any design work or planning application can begin, you need accurate existing drawings of the property. A measured survey is a non-negotiable first step — no architect can produce credible planning drawings without one, and any inaccuracies at this stage create problems throughout the entire process.
Budget between £750 – £1,500 depending on the size and complexity of the building (based on average house size that is capable of 7-8 hmo bedrooms).
Architect Fees
Once you have existing drawings, the architect will typically begin with a design feasibility study to explore how the layout can work for a large HMO. This is followed by the full set of planning drawings required for your application. Because every property is different — different layouts, different constraints, different council requirements — architect fees are quoted on a bespoke basis.
Get in touch with us directly if you would like a free bespoke quote for your project.
Planning Consultant Fees
For a Sui Generis HMO, it is advisable to also engage a planning consultant alongside your Architect. Their role covers the planning statement, thorough policy research, and active negotiation with the council during the application process. A well-crafted planning statement can be the difference between approval and refusal.
Expect to pay between £1,500 – £3,500 for this service.
Council Planning Application Fee
This is the statutory fee paid directly to your Local Planning Authority when you submit a full planning application with change of use through the Planning Portal.
For most Sui Generis HMO planning applications in 2026, the fee is normally £701. Unlike the professional fees above, this is a fixed government charge — it does not vary between councils. Fees do change over time so please check Planning Portal for latest LPA fees.
Parking Survey
Many councils will require a parking survey as part of a Sui Generis HMO application, particularly in areas where on-street parking pressure is already high. The survey assesses local parking demand and demonstrates that the proposed development will not have an unacceptable impact on the surrounding streets.
Budget between £500 – £1,500 for this, depending on the scope of assessment required.
Additional Surveys & Reports — depending on your site
The fees above cover most standard applications, but your specific property or site may trigger one or more additional requirements. Councils can request:
A bat survey if the building is older or has roof voids that could provide roost habitat.
An ecology survey may be required if there is any significant planting or natural features on the site.
A tree survey becomes relevant where mature trees are close to the building or within the application boundary.
If the site sits within a flood zone a flood risk assessment will be needed.
Properties near busy roads or commercial uses may require a noise impact assessment.
If your property is a listed building or within a conservation area, a heritage impact assessment is likely to be required.
Each of these carries its own cost, which varies by specialist and scope, so factor in a contingency if any of these scenarios could apply to your property.
An Important Change for 2026:
It is now more important than ever that all supporting documents — surveys, statements, drawings, and assessments — are submitted as part of your original application.
Previously, additional documents could be introduced at appeal stage. That option has been removed. If your application is refused and you appeal, you cannot supplement your case with new evidence.
Get it right the first time.
If you are planning a Sui Generis HMO conversion and want to understand what the full cost looks like for your specific property? Get in touch — we provide bespoke quotes and can walk you through the process from start to finish.