HMO Conversions Hillingdon

HMO conversion in Hillingdon now starts with planning permission everywhere in the borough. The council's borough-wide HMO Article 4 direction means a family house let to 3 or more unrelated sharers needs consent, and a boroughwide additional HMO licensing scheme now covers smaller shared houses as well as the mandatory licence for larger ones. We build shared houses and upgrade existing HMOs to the council's standards for room sizes, kitchens, bathrooms and fire safety, working to the consent and the licence conditions the landlord obtains.

One exception matters here: a flat in a purpose-built block of three or more self-contained flats falls outside mandatory licensing, although a council's additional scheme can still cover it.

In Hillingdon, a light HMO conversion for four to six tenants typically costs £40,000 to £75,000 in construction, or £90,000 to £150,000 with an en-suite to every bedroom (indicative London ranges, Mayfair Studio and LetCompliance, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Hillingdon: we build the fire doors, detection, bathrooms and kitchens to the council's HMO standards, the landlord applies for the licence, and a registered electrician certifies the electrics.

Planning permission for a Hillingdon HMO after the Article 4 direction

Across every part of Hillingdon, letting a house to 3 or more unrelated sharers now needs planning permission. The council decided at its Full Council Meeting on 27 November 2025 to implement the borough-wide HMO Article 4 direction. Nationally, Class L lets a house change from C3 to a small C4 HMO as permitted development, and it never allowed one house to become two separate HMOs. In Hillingdon the direction takes away even the single change, so the landlord applies before any room is let.

Bigger houses in multiple occupation face a separate test. The London Plan glossary puts HMOs for three to six people in Use Class C4 and HMOs for more than six in the sui generis class, which always needs planning permission in its own right. Hillingdon Policy DMH 5 asks a large HMO to show good access to local amenities and public transport and satisfactory living conditions. A shared house near Uxbridge or a station answers that test more easily than one on an outlying estate.

Housing in Hillingdon

For Hillingdon the Council Tax list gives about 118,240 homes; by type 34% flats and 66% houses, by age 59% post-war, 37% interwar and 4% older than 1919.

Mandatory and additional HMO licensing in Hillingdon

Licensing runs alongside planning, and a house can need both a consent and a licence. In Hillingdon, mandatory licensing applies to large HMOs with 5 or more unrelated people living in them. The boroughwide additional HMO licensing scheme picks up shared properties with fewer than five residents from two or more households. Cabinet agreed to adopt it on Thursday 19 February 2026, after a 10-week public consultation, and the council says it works alongside the borough-wide HMO Article 4 Direction.

The deadline to apply for a Hillingdon additional HMO licence was Sunday 23 August 2026, with enforcement possible from Monday 24 August 2026. GOV.UK says renting out an unlicensed HMO can lead to an unlimited fine, so an existing shared house without a licence needs attention now. The licence application is the landlord's to make. Our part is the building work the licence conditions call for, finished before the council's inspection rather than after it.

Hillingdon HMO room sizes, kitchens and bathrooms

Hillingdon's HMO standards set the layout before a wall is built. Where a shared lounge is provided it should be 10m2 or more, and any floor under 1.53m of headroom, in a room under the roof slope for instance, is left out when a room is measured. A kitchen set inside another room adds 3.7m2 to the floor area that room must have. The national licence minimums apply on top: 6.51 square metres for one adult, 10.22 for two, and no room under 4.64 square metres used for sleeping, so the room schedule is measured, not estimated.

The services follow the head count. Hillingdon wants a fixed impervious worktop of 1500 x 600 mm or more per five sharers of one kitchen, and a bathroom with a fixed bath or shower per five occupiers. Extract has to be humidistat controlled, with 60 l/s from a kitchen and 15 l/s from a bathroom as the minimum rates. We set out the kitchen runs, bathroom positions and duct routes from those numbers at first fix, so nothing has to move after an inspection.

Fire safety, sound and energy in a Hillingdon shared house

Fire safety is the core of any Hillingdon HMO conversion. The LACORS housing fire safety guidance is the recognised guide, and the council's own fire standards and the licence conditions set the detail. In a two storey shared house that usually means fire doors with self-closers to every bedroom and the kitchen, an interlinked mains-powered detection system, and a protected escape route down the stair to the front door. We build to the layout the landlord's designer or fire risk assessor fixes.

Sound and energy come next. Bedrooms either side of a stud wall need sound insulation in the wall and the floors between lettings, because sharers keep different hours and noise travels through light partitions. Since 1 April 2020 a Hillingdon HMO covered by the MEES Regulations cannot be let, or go on being let, below an EPC rating of E without a valid exemption. Loft insulation, heating controls and a modern boiler usually go in while the rooms are empty.

• Hard-wearing floors, finishes and decoration for a let house
• Thumb-turn bedroom locks that open from inside without a key
• Electrics extended to every bedroom, certified by a registered electrician

VOA Council Tax stock of properties, March 2025, for all 32 statistical areas in Hillingdon. Counts rounded by the VOA.

For the wider picture around hmo conversions in Hillingdon, see bathroom renovation in Hillingdon, our Hillingdon area guide, bathroom fitting in London, what a snagging list covers, our London hmo conversions page and Small Bathroom Ideas.

The GS Renovation Difference in Hillingdon

Landlords in Hillingdon use GS Renovation for an HMO conversion when they want the building work matched to the licence conditions from the start. We read the planning consent, the fire strategy and any licence conditions before we price, then give you a written quote after a site visit and a written programme. The founder, Abdelaaziz Saaid, oversees the fire doors, detection and room layouts on site. A registered electrician certifies the alarm and electrics, and a gas engineer on the Gas Safe Register does the gas work.

• EPC upgrades done while the walls and floors are still open
• Neighbours given notice before the noisy stages
• Article 4 and licence position checked before a room is priced

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254).