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Red-brick Victorian mansion houses on a Kensington street in London, blue sky, white sash windows and a stone balcony

House to Flats Conversion Planning, design and build under one contract, and a free check of how many flats your house can take

Our track record

100% of projects delivered ahead
of programme and on budget

Our team's record

  • 10,000+homes through planning, Development Director's record
  • 4,000+homes delivered by our Development Director
  • 4 weeksto test a vacant St John's Wood building as flat schemes, drawn and costed
  • 0snags at handover, the completion file ready for your buyers

How many flats, and will the council agree?

Every house conversion turns on two answers: how many flats the house can hold to the space standards, and whether your borough allows the split at all. Many London boroughs protect smaller family houses, often those under 130 m² as first built. We answer both before you pay for drawings. For a vacant corner building on Allitsen Road, St John's Wood, we drew and costed four schemes, from four to seven flats, in four weeks.

Then one contract carries it to the keys: the planning application, new structure, fire and sound separation between flats, separate services, kitchens and bathrooms, and every certificate your solicitor and buyers ask for.

Craftex design options summary for Allitsen Road: four schemes stacked floor by floor, from four to seven flats with their sizes

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Everything a house to flats conversion needs, under one contract

Victorian red-brick and white gabled houses with bay windows along a St John's Wood street

The planning route

Splitting a house always needs full planning. We read your borough's rules on family homes and minimum house sizes first.

Craftex ground floor plan for Allitsen Road: two flats in colour around a shared stair and lift

Layouts to the space standards

Every flat drawn to the national space standard and London's 2.5 m ceilings, so the count you plan is the count you build.

Craftex section drawing for Allitsen Road showing the ground, first and second floors stacked with their heights

Structure, fire and sound

New steels where walls move, fire-resisting floors between flats, a protected stair and sound insulation tested before completion.

Services cupboard with meters, distribution boards and cable runs, fitted during the works

Services split for each flat

Separate meters and supplies, new soil stacks and drainage, and heating and ventilation sized for each home.

Period staircase with a white balustrade, carpet runner and herringbone landing, seen from above

Ready for leases and titles

Common parts, front doors and floor plans set out so your solicitor can grant a lease and register each flat.

Finished bedroom in a London period home with tall sash windows, an upholstered headboard and a glass ceiling light

One contract to the keys

Kitchens, bathrooms and finishes built by our own teams and handed over with zero snags.

How it works

How a house to flats conversion runs with Craftex

01

Free layout check

Send us the address, rough floor areas and a few photos. We say how many flats the house could take and what your borough's policy says.

02

Survey and options

We measure the house, draw layout options to the space standards and price each one, so you choose the scheme on numbers.

03

Planning application

We prepare and submit the full application: drawings, design statement, heritage notes where needed, bins and cycles. One scheme goes in.

04

Technical design, figure

Structure, fire strategy, acoustics, services and the Building Regulations application, then the figure we sign, shared with your lender.

05

Build and handover

About 60% of the labour is our own. Sound tests, the completion certificate and every service certificate come with the keys.

Cover of the free Craftex Guide to Planning and Prior Approval

The Craftex Guide to Planning and Prior Approval

Converting a house into flats is a full planning application. The guide sets out the routes side by side, the time limits set by law, a document checklist for your application and the refusal reasons we see most.

Our promises

Six promises, written into your contract

Not marketing lines. These are the terms of every contract we sign.

  1. One team from survey to keys

    Planning, design, structure, services and fit-out under one contract, so no gap opens between consultants.

    Allitsen Road: four flat schemes, one owner of every answer

  2. The signed figure is the figure paid

    Changes priced and agreed in writing before the work.

    Google review, shop into two rental flats in Chelsea: the quote held

  3. Ready for your sale or letting date

    One programme, with design and procurement run in parallel.

    Office into 8 apartments: the client exited 2 months ahead of competing timelines

  4. Built with our own labour

    Around 60% of the people on site are ours, so no trade holds up the programme.

    Google review, warehouse near Tower Bridge into 4 flats: on plan and on time

  5. Cover your lender accepts

    £10M public and employers' liability, professional indemnity on request, ISO 9001, 14001 and 45001, CHAS, SafeContractor.

    Collateral warranties from our consultants and design team

  6. Zero snags, every certificate

    Handed over with the file your solicitor, lender and buyers ask for.

    12-month defects liability, extendable; warranty up to 10 years available

Example house to flats conversion quotation from another contractor with the total circled, and the note: send it to us, we will beat it

Already have a quote? Send it to us. We'll beat it.

Got a price from another builder for your conversion? Send it over. After a survey we put our figure and programme against it for the same scope. Or talk it through with our team first.

Compare your quotes

Where house to flats conversions usually go wrong, and what we do instead

Hold any quote up against this. The risks are the same on every conversion; who carries them is not.

AreaThe usual riskWith Craftex
Who is responsibleAn architect, a planning consultant, an engineer and a builder, each pointing at the other.One contract and the same directors from the first visit to the last certificate.
The flat countFive flats on the sketch that only pass the space standards as four.Each layout checked room by room against the standards before you pay for planning drawings.
The planning routeAn application that ignores the borough's family-housing policy and is refused months later.Policy, size thresholds and recent decisions on your street read before anything is submitted.
The final billA rate per square metre given before anyone has lifted a floorboard.A figure built from the survey and drawings, signed before the first day on site.
Compliance and sign-offFailed sound tests at the end, and fire separation found wanting by building control.Fire and acoustic separation designed in from day one; we run every approval and certificate your buyers' solicitors need.
HandoverA snag list, missing certificates and a sale that waits on paperwork.Zero snags, certificates and warranties in the folder on handover day.

House to flats conversion cost in London, 2026

Our 2026 rates per m² of gross internal area, construction only, ex VAT and fees. The last column applies the same rate to a 65 m² flat, for scale. We build from £100,000 to £10M and above; your fixed figure comes after a survey.

TierWhat it covers£/m²Per 65 m² flat
LightA sound house split along its existing floors: new partitions, fire and sound upgrades, kitchens and bathrooms, standard finishes1,150£74,750
StandardNew steels and openings, a protected common stair, new soil stacks and supplies, mid-range specification1,550£100,750
High-endBack to the brick: structural rework throughout, upgraded windows where consented, high-specification kitchens and bathrooms2,100£136,500
Extra: new floor areaA rear, side or loft extension that adds a flat, per m² built2,200On survey
Council planning feePer new flat where there are fewer than ten, in force since 1 April 2026; CIL and utility connections are separaten/a£610

Free cost calculator

What will your house to flats conversion cost?

Enter the house's gross internal floor area and pick a tier. You get a range at once, based on our 2026 London rates.

Your estimateEnter your spaceex VAT and fees Get a fixed figure

Indicative, ex VAT and fees, for the build alone. New floor area from an extension adds about £2,200 per m² built. A survey comes before your fixed figure.

Our team

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House to flats conversion: your questions

Do I need planning permission to convert a house into flats?

Yes, always. Using one house as two or more separate homes is a material change of use in planning law, and no permitted development right covers it, so it needs a full planning application. A listed house also needs listed building consent. The council fee is £610 for each new flat in a scheme of under ten. Read the planning rules for converting a house and the 2026 fee schedule.

How many flats can my house take?

As many as meet the space standards with daylight, storage and a safe escape route. In London a one-bedroom, two-person flat needs 50 m² and a two-bedroom, four-person flat 70 m², with a 2.5 m ceiling over at least 75% of the floor. The stair, a lobby and fire separation take space too, so the count is set room by room, not by dividing the floor area.

How long does a house to flats conversion take?

By law a council has 8 weeks to decide a minor application, which covers fewer than ten flats, and many London decisions run longer on an agreed extension. Party wall notices and technical design run alongside. On site, the date is fixed in your contract rather than quoted as generic weeks. See how long planning permission takes.

Is VAT charged at 5% on a house to flats conversion?

Building work on a conversion that changes the number of homes, such as one house into three flats, can qualify for the reduced 5% rate. The contractor has to apply it correctly, so we confirm the rate in writing before the contract.

Do I need a party wall agreement?

If the work cuts into a shared wall, sets steel into it or digs foundations near a neighbour, the Party Wall Act applies and notices go out before work starts. We serve them early so the award does not hold up the start. Read our party wall guide for developers.

What size of project do you take on?

Construction from £100,000 to £10M and above; design commissions start at £15,000. Still looking for a house or building to convert? Our development land and site sourcing service finds one and tests it before you buy.

Will my borough allow the house to be split?

It depends on the local plan. Many boroughs protect smaller family houses: Lambeth protects homes under 130 m² as originally built, and Brent looks for 130 m², or a house that can reasonably be extended to it, plus a three-bedroom flat. Some want a family flat with garden access on the ground floor. We read the policy and recent decisions on your street in the free check.

How much does it cost to convert a house into flats?

Our 2026 rates run from £1,150 to £2,100 per m² of gross internal area for the build, ex VAT and fees: about £75,000 to £137,000 for a 65 m² flat. Structure, the common stair, drainage and the specification move a house between the tiers. Planning fees, CIL and utility connections come on top, and the figure we sign follows a survey.

Which Building Regulations apply when a house becomes flats?

The conversion is a material change of use under the Building Regulations too. The main items are fire-resisting separation between flats and a protected escape route, sound insulation proven by testing before completion, structure checked by an engineer, ventilation, energy upgrades, drainage and separate services. Old timber floors are where fire and sound upgrades cost most.

Is Community Infrastructure Levy charged on a house conversion?

New homes are potentially liable for the Mayor's and the borough's CIL. Floorspace in lawful use for six continuous months in the three years before permission can be deducted, which often brings an occupied house down to little or nothing. A house left empty for years can lose that deduction.

Can I sell the flats separately?

Yes, once each flat has its own lease and the freehold or a management company holds the common parts. Your solicitor drafts the leases and registers the titles; we set out the plans, front doors and common parts to suit, and hand over the certificates buyers' solicitors look for. Check your lender's criteria for converted flats early.

What our clients say

See all reviews on Google
  • Hired Craftex for our conversion project. We had to convert a 600m2 office into 8 apartments. Guys did an excellent job in terms of program efficiency and quality of the finishes which gave us a big upside to exit the project 2 months faster than other competitors’ timelines.

    Misha Levit

  • Great experience from start to finish. Communication was clear, the workmanship was excellent, and the whole project was managed professionally.

    Rhea Langford

  • I’d like to thank the team at Сraftex for the work they did on our office.
    It was really important for us to get the work done quickly, but without compromising on quality, as we regularly have clients and guests visiting and needed to move into the new office within a month.
    We spent around two weeks discussing and agreeing all the details before the work started. What I really appreciated was that everything we agreed beforehand was actually followed through during the job. The work was also completed on time.
    Thanks to the whole Сraftex team for a great job. I’d definitely use them again if we need any work done in the future.

    IURII PYLYPETS

  • We recently worked with Craftex and honestly couldn’t be happier with the results. From start to finish, the team was professional, reliable, and highly skilled. The quality of workmanship exceeded our expectations, and everything was completed on time and to a very high standard.
    Communication throughout the project was excellent, and they always went above and beyond to make sure we were satisfied. It’s rare to find a construction company that combines professionalism, attention to detail, and great customer service so well.
    Without a doubt, Craftex is one of the best construction companies we have ever worked with. Highly recommended to anyone looking for quality and trustworthy builders.

    Adam Miah

  • Craftex has completed a range of both small and large-scale projects on our commercial property with exceptional precision and quality. Dmitriy consistently delivers courteous, prompt service and has shown great flexibility in accommodating last-minute changes to plans and timelines. I highly recommend Craftex for their professionalism and outstanding workmanship.

    Pascal Hunt

  • Great company to work with as always. Super flexible at dealing with evolving requirements and fast deployment and execution.

    Akshay Khanna

  • Hired Craftex to do the full design and fit out of my gym in Chelsea. Super efficient and fast team. They gave the best price and a proper fast track program. We managed to open in less than 6 weeks with no headaches or surprises during construction. Quality was great, we had zero snags on completion. I’ve worked with a few companies before but these guys really impressed me from project management to how they treat the client. Top GGs.

    Александр Хоменко

  • I worked perfectly with Sviat and Joe, with their architect they came up with a very smart design for our office to fit more desks and optimise the space to its maximum capacity. They also did excellent value engineering on the MEP design proposed by others, allowing us to save around £50K. The quality and speed were outstanding we finished two weeks ahead of schedule. Highly recommend these guys.

    John Smith

  • Happy with the end result. Tight timeline but they pulled it off. The team worked late shifts and even weekends to help us open the doors on schedule. Site was always left tidy at the end of the day and no surprise charges either. Good communication throughout. Would definitely use Craftex again.

    Pawel Kamionka

  • Highly recommended!
    Craftex are the kind of fit-out contractors in London you can truly trust. From the very first meeting, they understood our vision and gave practical ideas to make the most of our space. They turned our old storage area into a clean, efficient, and well-organized warehouse. The team was professional, easy to work with, and clearly took pride in their work.

    Monika Kamionka

  • We brought in Craftex to refurb our London office and honestly, they made the whole thing way easier than we expected. They listened, suggested ideas we wouldn’t have thought of, and explained everything clearly. Not the cheapest quote we got, but the end result shows why, the place looks modern, clean, and our team actually enjoys being here now. Communication was spot-on too. No chasing and confusion, deadlines were hit. If you want people who genuinely care and don’t treat your project like “another job,” I’d recommend them.

    A Google User

  • Sviat and his team at Craftex were brilliant to work with on our office redesign. From the first meeting, they took the time to understand how we actually use the space rather than just pitching generic solutions. They came back with clever, practical ideas to maximise use of the space and get more employees and desks inside . Every step was handled professionally, and the process felt surprisingly smooth for a project of this size. They finished one week ahead of schedule, and the transformation is clear — our office feels brighter, more functional, and much more welcoming. I’d happily recommend Craftex to anyone who wants a reliable design team that also makes the journey enjoyable.

    Cucu Iulian

  • We recently worked with Sviat and the Craftex team on a complete warehouse refurbishment, and the results have been outstanding. From the very beginning, their team was professional, organized, and attentive to every detail. The project was completed on time and within budget, without disrupting our day-to-day operations.

    Simone Racaku

  • My experience with Craftex was excellent from beginning to end. They took the time to really listen to what I wanted and then offered practical suggestions that made the design even better. I always felt like they cared about creating a space that worked for me, not just one that looked nice on paper. The end result is an office that feels stylish, welcoming, and very functional for day-to-day work. The process itself was straightforward, well-managed, and never stressful. I’d definitely recommend Craftex if you’re looking for office design and build services in London — they made the whole journey a positive one.

    Ion Bounegru

  • I’m really pleased with my experience working with Craftex. As a commercial construction firm, they handled everything from start to finish without any unnecessary stress on my side. What impressed me was how they suggested practical ideas that improved the design while also keeping things realistic. The communication was always clear, so I never felt out of the loop. The project ran smoothly, deadlines were met, and the end result is exactly what I was hoping for — a space that feels both functional and modern. It’s not easy finding contractors who are this reliable, but Craftex definitely proved they can be trusted.

    Taron Papoyan

  • I had an amazing experience working with Sviat and the Craftex team on our office fit-out in London. They were always professional, responsive, and quick to offer the best advice whenever decisions needed to be made. I really appreciated how they balanced style with practicality — the office doesn’t just look fantastic, it works perfectly for our team. Everything was done with care and attention to detail, and the project never felt overwhelming because they managed it so well. Communication was clear from start to finish, and I always felt involved in the process. I would happily recommend Craftex to anyone looking for a trustworthy contractor.

    Artur Dvorak

  • Craftex carried out a warehouse fit-out for us, and I couldn’t be happier with the outcome. The space has been completely transformed into a highly organized and efficient environment that makes our daily operations much smoother.
    The team was professional but also very approachable — I always felt comfortable asking questions or giving feedback. They came up with smart, practical solutions that worked perfectly for our setup, and everything was explained clearly along the way.
    The best part was how they stuck to the agreed timeline, finishing on schedule without cutting corners. It’s rare to get both quality and reliability, but Craftex delivered both.

    Roma Shchukin

  • We’re extremely happy with Sviat and the Craftex team’s work. They suggested clever ideas, managed the project efficiently, and delivered a functional, modern space. The team was easy to communicate with and very professional throughout the process!

    Polina Lysenko

  • I can honestly say our office has been completely transformed thanks to Craftex. From the very first meeting, the team was approachable, professional, and full of creative ideas that really made sense for our business. They didn’t just focus on how the space would look but also how it would work for the team day-to-day. The new layout is efficient, modern, and welcoming, and you can tell they really thought about the details. The whole process was smooth and surprisingly stress-free. They kept me updated at every stage, which gave me confidence. I’m really happy with the results and wouldn’t hesitate to recommend them to anyone.

    Mykyta Khadzhynov

  • The results from Craftex’s commercial refurbishment in London are fantastic. The team was friendly, clear in communication, and made sure the project stayed on track. The workspace now feels efficient, welcoming, and modern. Definitely a team you can trust!

    Alaa Betar

  • We hired Craftex for a commercial ground floor fit-out with 2 flats above. There were some minor co-ordination hiccups with third-party suppliers but the team kept it moving. Finish quality was strong. Kitchens and doors look great. I have already asked them for a quote on the next project.

    Ben Edell

  • These guys actually deliver. They handled our first industrial to residential conversion near Tower Bridge, turned an old warehouse into 4 modern flats. They stuck to the plan, kept the site clean and the timing was on point. No hidden extras, no drama, just a professional construction company in London that gets the job done.

    Богдан Главацкий

  • We recently hired Craftex for a commercial office fit-out project in Central London, and overall, we’re really happy with the result. There was a delay on our side with a custom glass partition supplier, but the Craftex team managed the construction schedule very professionally and kept everything on track. Their guys worked clean, respected our workspace and IT setup, and kept the site tidy throughout. If you're looking for a reliable office refurbishment company in London, I’d definitely recommend Craftex. Would use them again without hesitation.

    Ardian Beleshi

  • This was a full high-end renovation of my Victorian rental apartment in Westminster, just off Sloane Square and Belgravia. The scope included full fit-out: electrics, plumbing, a new bespoke kitchen, and a luxury bathroom refurbishment. Craftex took care of everything and made the process easy. They weren’t the cheapest, but you can tell they really know what they’re doing when it comes to prime London property renovations.
    The team was professional, organised, and genuinely seemed to care about getting everything right. I was especially impressed with the quality of the finish – the attention to detail really shows in every corner.
    I’m very happy with the results and would definitely recommend Craftex to anyone looking for reliable, high-quality renovation work in Central London.

    Наталия Цимбалюк

  • I was stressed about timing since we had bookings lined up, but they smashed it. Even worked Saturday to finish the floor. My clients love the look — the beauty salon fit-out turned out exactly how I wanted. Couldn’t have pulled it off without their help. Genuinely appreciate the way they communicated throughout the refurbishment. If you need reliable help with beauty salon design or fit-out, especially in a place like Chelsea — these are the guys.

    Rami Jusupova

  • We used Craftex for a shop-to-flat conversion in Chelsea — turning an old retail space into two rental units. Access wasn’t the easiest, but the guys handled it well, no drama. Quote was clear, no hidden extras, and they actually stuck to it, which is rare. Finish came out solid, exactly what we needed for rentals. Joe (PM) kept things ticking and communication was always on point. All in all, smooth job — would use them again for sure.👍

    Apartify Estates

  • Fuse Energy hired Craftex on the fit-out and installation of our engineering and research centre, which included electrical, heating, lighting, plumbing, and ventilation upgrades. They delivered everything to a high standard and were proactive throughout — even working weekends to help speed up the programme, despite not being contracted to. They managed last-minute changes very well, communication was clear and consistent, and the team was professional from start to finish. We’d happily recommend Craftex to anyone needing a reliable construction partner.

    Hainro Eybers

  • Holistic therapy space fit-out
    Super impressed. I had a very specific vision for the studio. calm tones, soft lighting, hidden storage etc. the craftex team just got it. build was done quicker than I expected and the guys were polite, tidy and actually listened. we had 2 snags on day one but they fixed it before the week was out. worth it for the peace of mind.

    Dariia Shvyryda

  • Made a full refurbishment and redesign of our Central London office. Fantastic work, quality service and reliable people. Can recommend it to everybody

    Nikita Nigai

  • Amazing experience with these guys. I trusted them my apartment in London and Business. They are always accurate, very professional, responsive and neat. They would always advice me right things for my best interest. I had luxury experience with them and I would definitely recommend Craftex to everyone.

    Motush Motushev

  • Could not be HAPPIER with Sviat and the Craftex team, they certainly showed me that they’re the number one office design company in London that we’ve had the pleasure of working with. They gave us a unique design just like we wanted, and we loved the first initial draft of the concept. Also have to give them props for Construction, I gave them a tight timeline as we needed to move our team in ASAP, so they pulled double shifts and I didn’t see a drop in quality. Will be to talking to the team when we move up to our next bigger office. Highly recommended A+++

    Mikhail Burdoev

  • Very professional company. Craftex did brilliant minimalistic design and completely refurbished my apartment to the highest quality.

    Vlad

  • I and my husband are very satisfied with Craftex's service and customer support. We bought a house in Hampstead and wanted to redesign and renovate it. On our initial free consultation with Sviat, we found out that we actually can do loft conversion and rear extension and add value to the property straight away.
    We worked with the Craftex design team to bring our vision to life and deliver planning approvals. At that time guys started stripping out to save time on the construction programme as we wanted to move in ASAP.
    We worked with very experienced project director Konstantin who was responsible for all aspects of project delivery from design to construction with a very good eye on details and customer care.
    We saved a lot of money by having professional advice from the start. Project management and quality at Craftex are at the highest level. Many thanks to Craftex Team.

    Lia Lavryk

  • ISO 9001
  • ISO 14001
  • ISO 45001
  • CHAS
  • Constructionline Gold
  • SafeContractor
  • TrustMark
  • FMB
  • NICEIC
  • NAPIT
  • MCS
  • CSCS
  • Considerate Constructors
  • RICS, Royal Institution of Chartered Surveyors
  • RIBA, Royal Institute of British Architects
  • ARB, Architects Registration Board
  • Public & Employers' Liability £10M
  • Professional Indemnity £10M
  • ISO 9001, 14001 and 45001 certified

Send us your house for a free layout check

Tell us the address and roughly how big the house is. We will tell you how many flats it could hold, where your council stands on the split, and the next steps.

Unit 5, 160 Buckingham Palace Road, London SW1W 9TR

info@craftex.co.uk

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