Flat & Apartment Architects in London

A flat project is two projects at once: a design project and a consent project. The design usually aims to win light, storage and a better sense of flow from a fixed footprint. The consent challenge is the lease — most significant alterations need the freeholder’s permission through a Licence to Alter, supported by drawings, and managing agents and their surveyors take a close interest in anything structural. Where the project is a full leasehold renovation, our flat refurbishment architects page covers that project type in detail.

Between flats, the details that matter most are the ones you cannot see: fire separation, acoustic performance and floor build-ups, structural openings, and the routing of services and risers. We address these explicitly in the drawings and coordinate structural engineers and other specialists so the package satisfies both the freeholder and building control.

Working within a fixed footprint is a design discipline, not a dead end. A great deal can be achieved by reconfiguring how a flat is organised — borrowing light, rethinking circulation, and replacing dead corridor with usable space — even where the structure and external walls cannot be freely altered because they are not yours to change. At the more ambitious end, two adjacent or stacked flats can sometimes be combined into a single lateral or duplex home, which is one of the most rewarding flat projects but also one of the most demanding on lease, structure and consent. We test what your demise and the building genuinely allow before designing.

Much of prime London’s flat stock sits in mansion blocks and managed buildings, which bring their own rules. Communal heating, water, ventilation and risers have to be respected; the managing agent and the freeholder’s surveyor set conditions and approve contractors; and access, deliveries, hours of work and protection of common parts are all controlled. These constraints shape what is feasible and how a project is delivered, so we design and plan the works with the building’s management in mind from the start rather than running into its rules halfway through.

A flat project moves on two tracks: the design, and the consents that allow it. Most significant alterations need the freeholder’s permission through a Licence to Alter, and external changes generally need planning permission as well, since flats have no permitted development rights. We develop the design and the consent strategy together — preparing the drawings the freeholder’s surveyor and the council each need — so the scheme you commit to is one you are actually able to build. For the consent process itself, this works hand in hand with our Licence to Alter and estate and freeholder consent services.

Most London flats cannot grow sideways. Value comes from reworking plan, light and storage: moving kitchens and bathrooms where services allow, reclaiming corridors, opening or closing rooms for how you live now. We test options against structure, stacks, windows and daylight so the preferred plan is buildable, not just attractive on paper.

Combining two flats or linking floors raises extra lease, fire and freeholder issues. Those projects need early route advice before design freezes.

The lease often dictates what may change. Structural openings, wet-room moves and floor build-ups commonly need a Licence to Alter. We design with that process in mind and prepare the pack freeholder surveyors expect — structure, acoustics, fire and waterproofing notes included. Purely cosmetic redecoration rarely needs consent; anything that touches fabric usually does.

Building regulations drawings sit alongside freeholder consent. One measured survey should feed both so you do not pay for conflicting redraws.

Purpose-built mansion blocks and house-to-flat conversions behave differently. Blocks often have strict managing-agent rules and shared services; conversions may hide odd levels, thin floors and improvised structure. We survey carefully and design interventions that respect how the building actually works, not a generic open-plan template.

Where external change is proposed, planning may join the lease track. Internal-only schemes more often run on freeholder plus building control. We confirm the map at the first review.

Freeholder consent is not the only permission a structural flat project can need. The walls and floors that separate you from neighbouring flats are shared structures, so cutting into them to form an opening, inserting beams that bear on them or changing a floor build-up can bring the Party Wall etc. Act into play alongside the Licence to Alter. The two run in parallel and neither substitutes for the other: the freeholder consents as your landlord, while the Act protects the owners on the other side of the structure you are working on, and in a block those adjoining owners can include several leaseholders as well as the freeholder itself.

Notices run statutory periods of one or two months depending on the type of notice, and if a neighbour dissents, surveyors are appointed and an award is settled before that element of the work starts. We flag notifiable work early in the design so the notices can run while the freeholder's surveyor reviews the pack, rather than being discovered a fortnight before the builder is due to start.

When a Licence to Alter application goes in, the freeholder's surveyor is not judging your taste. They are checking that the structure of the building is protected, usually by asking for an engineer's calculations for any opening; that a relocated bathroom or kitchen will not leak or drain into trouble, so waterproofing details and drainage routes are examined; that floor build-ups keep acoustic separation to the flat below; and that services connect into the building's systems without overloading risers everyone shares. Around the technical pack sits the licence itself, which typically sets conditions on working hours, protection of common parts, contractor insurance and reinstatement, and the lease usually makes the leaseholder responsible for the freeholder's reasonable professional costs in reviewing it all.

Most stalled licences stall for the same reason: a thin pack submitted early, followed by months of piecemeal queries. We prefer to submit once, complete, with structure, acoustics and waterproofing already coordinated, and our estate and freeholder consents service handles the process where a landed estate or institutional freeholder is involved.