Loft conversions in London

How to gain space and value with a loft conversion in London

Adding a loft conversion to your property in London is a fantastic option to get more space. Having extra room for bedrooms and an extra bathroom, for example, can increase the market value of your property substantially.

As for all extensions of houses or flats in London, there will be different types of loft conversions, according to the area, the type of building, the neighbourhood and the council rules.

With houseUP, we work in London in all the councils inside the M25 belt and have experience liaising with the planning and building regulation authorities across the whole Greater London area.

Why do a loft conversion in London with houseUP

With a loft conversion it is important to understand the technical constraints and transform them into opportunities to maximise your results.

When doing an attic conversion, for example, head height is one crucial factor to take into account in a loft conversion. Planning regulations have requirements for the minimum head height. In general, rooms with higher ceilings are more pleasant to live in and have a higher value on the property market. In houseUP we regularly use our technical expertise to target head height maximisation.

In some cases, the structural design of a loft conversion can be optimised for head height, installing floor joists that are flatter and placed at a closer distance from each other. This way you can achieve the same structural performance, with a benefit that is perceivable in the actual usage of the space.

In other cases we have designed an alternative timber structure, with no steel, to adapt to the characteristics of the existing building, reducing the cost and the duration of the works.

Other examples are optimised structural solutions that minimise the cost of party wall agreements. Our clients saved huge costs because we designed and implemented structural alterations that did not impact the party walls.

Even if a loft conversion can be a straight forward construction project, small adjustments can make a big difference in the quality and value of the final results.


Here’s what to expect when working with houseUP


  • Make the most of your property’s potential with loft conversion specialists for planning and designing
  • Get the planning for your loft conversion sorted in a smooth hassle-free process
  • Have all the building regs for your loft conversion approved to start the work timely
  • (in-house) Use our in-house team of loft conversion professionals for the most relevant technical competence and experience
  • (in-house) Prepare all the documentation for your loft conversion project, including H&S and planning conditions


  • Get the best specialised building contractor team for loft conversions
  • Have a structural expert on-site to direct the structural works and make sure safety and compliance are in check
  • Use the best tradespeople on site at the right time, from electricians and plumbers to carpenters, decorators and more
  • Access exclusive finishes directly from Italy at discounted prices, including porcelain tiles and staircases
  • Achieve the maximum from your loft conversion, including light, head room, insulation and finishes down to the smallest detail

Project management

  • Have a specialised project manager with experience of loft conversions in your area
  • Ensure Health and Safety, party wall procedure, planning authorities, neighbours are managed promptly and professionally
  • Optimise orders, personnel on site, building regs visits and other arrangements for effective time management
  • Make sure the disruptions to your normal life are minimal, so that you can keep living or move in as soon as possible
  • Follow a clear decision making process to be on top of what’s happening on site

Digital platform

  • Take control of your loft conversion project through houseUP dashboard, to monitor progress and costs, see real time photos and videos, post comments and direct questions
  • Get involved in the process, the schedule, the choice of materials and finishes with a single source of truth for the decision making
  • Have access to a dedicated channel on houseUP chat platform, for real time issue management and direct conversations with the project manager
  • Keep a written record of all the conversations, questions, issues, decisions, with easy search and documentation sharing, avoiding long email threads with too many participants

Requirements for loft conversions in London

Planning permission

houseUP has experience in all councils in London, to help you understand the rules and make the best decision for your loft conversion.
We can advise on when your attic conversion can be done within permitted development scheme and create all the documentation. We can assist in the process to obtain the planning permission, in case it is needed.

Building regulations

Our design and construction teams make sure your loft conversion meets all the regulation regarding health and safety, structural soundness, energy performance and sustainability.
All loft conversions by houseUP are released with a building regulation compliance certificate, together with all the other relevant certificates and warranties for works, materials and appliances.

Party wall agreement

Party wall agreements are required very often for loft conversions in London, in the case of adjacent buildings. The party wall agreement process can be time consuming and expensive, especially when multiple parties are involved, like free holders, lease holders and tenants.
houseUP has extensive experience in handling party wall agreement process in a smooth and cost effective way. We use our technical competence to find the solution that work best, also keeping the party wall requirements into account.

Headroom requirements

The minimum headroom requirement for finished loft conversions in London is 1.90 m. Although compliant with regulations, a head height of 1.90 m is not optimal and houseUP never delivered a loft conversion with head height lower than 2.20 m. To achieve this, we apply specific technical solutions to maximise the space and work around the physical constraints.

Conservation areas

It can be challenging to get planning permission for loft conversions in conservation areas. Thanks to our experience, we can help you with sourcing the right materials and submitting the optimal designs to meet the stricter planning requirements in conservation areas in London.

Listed buildings

When converting loft in a listed building, even small features and elements can fall under the protection rules.
houseUP has vast experience in liaising with heritage planning officers for listed buildings, and our building teams are competent and knowledgeable on how to operate on listed building loft conversions in London.

Our loft conversion process

1. Free site visit

One of our construction specialists comes to meet you in person and view the property

  • Meeting in person: understand what you want to achieve from your loft conversion
  • Seeing the place: view the loft to identify the challenges and the technical approach
  • Explore the neighbourhood: check other loft conversions in the area to understand the impact
  • Discussing your taste and needs: identify the priorities and the objectives of the loft conversion
  • Capturing the unsaid: collect details, expressions, moods to design uniquely for you

For a loft conversion in London, a site visit is crucial. Visiting in person allows us to gather visual information on the condition of the place. This is essential to identify issues, technical and regulatory constraints, and to become familiar with the neighbourhood, For example, it is easier to get permission for a loft conversion, following the type of conversion of other properties in your area.

Capturing the said and unsaid: how to achieve what you really want from your loft conversion


2. Vision brief and budgeting

One of our partner architects with extensive loft conversion experience in your area will take on your project, to understand your expectations, explain the cost options and translate your ideas in drawings

 (design and build package only)

  • Translating the vision: transfer on paper the ideas you shared
  • Defining the constraints: create a design proposal that is compliant with the council requirements
  • Understanding the options: help you identify the best ways to use your budget to achieve the best results
  • Connecting budget and design: create a planning permission package that aligns with your budget

The most important aspect of the It is important to touch base and keep everything aligned, your vision and our understanding, to make sure that your priorities are taken care of. Sometimes a small inexpensive solution can save a lot of money and make you happier than a complex and expensive detail. Creativity and design need to be all focused on light, head-height, family space, life style, taste, comfort.


Translating the vision: create drawings that express your ideas to paper


3. Design and planning

One of our partner architects produces all the documentation and drawings for the planning authority and manages the process to get your planning permission for your loft conversion

 (design and build package only)

  • Liaising with the planning authority: manage meetings, requirements and feedback
  • Preparing drawings and plans: submit complete docs to planning
  • Filing the application to approval: submit all the package for the planning decision
  • Producing pre-build package: include building regs plus specifications, party wall, leasehold management and more

Managing a planning permission application is a careful balance between realising your desires, maximising the potential of your property and managing the planning authority requirements. It’s very often a matter of details, studying the history of past decisions, appointing the right consultants and communicating effectively with the planning authorities. We always want to get approval as soon as possible, avoiding to file a proposal that is too conservative and won’t give you the home that you want.

Optimising the planning application: exploit your property’s potential within the planning constraints


4. Free construction estimation

One of our estimation specialists produces an accurate quotation for your project, including a break down of all the details and their cost

  • Defining the construction costs: evaluate the basic construction work
  • Estimating the options: optimise the choice of finishes and suppliers for the best result
  • Explaining the quote: communicate clearly what is included or not and what might be the impact
  • Communicating effectively: explain the process and the project program, define the communication channels, agree on the decision flow

Investing your money in a loft conversion can be a big decision, and we want to make sure you are in control of all the costs.
Most important of all, the price must be reasonable. Rogue companies often quote a very low price to get appointed for the project, already planning to charge extras to make up for the difference; if not done on purpose, a contractor might choose to abandon the project when they realise it’s not profitable.
Check our infographic on 8 interesting facts that a good construction estimation should take into account.

Putting your priorities first: using the money for what is important to you

Construction Victorian building conversion panelled round window in unit1

5. Build

The construction manager assigned to your project assigns a construction team to your loft conversion, produces the project time plan and manages the activities on site for the execution of the work

  • Creating the program: define a clear program to control the progress and prevent issues
  • Planning the work and executing on site: choose the most experienced teams in loft conversions, according to the building, the area, the type of conversion
  • Reporting and sharing info: give regular feedback and respond promptly to questions and requests
  • Setting up communication channels: dashboard, live chat, photo and video sharing using the latest tech solutions
  • Making timely decisions: follow a clear process for requests, approvals, last minute changes and all decisions

A loft conversion can cause disruption in your daily routine and sometimes require moving out from your property for the duration of the project. Working to high professional standards and delivering high quality is essential for us. But information sharing and effective communication can make the process less unpleasant and keep you in control.
We always have English speaking construction managers and dedicated communication channels for each loft conversion project.

Delivering up to the expectations: produce top quality results through a hassle- and stress-free process.

Construction Victorian building conversion The Old Foundry Exterior Rear Facade

6. Completion and handover

Your construction project manager defines the snagging list, ensures all the tiny details are taken care of and reviews everything with you to get to a successful handover of your loft conversion.

  • Completing the work: finalise all the construction works for you to move in
  • Checking all the details: compile a snagging list to sort out all the small details
  • Wrapping up all the final bits: complete the snagging and sign off the project

The very last few days at the end of your project can feel the hardest sometimes. You can’t wait to complete the works and start your new life and there are always the final details to smooth out. After all the waiting and the disruption during the works, and then all the small details to be finalised!
That is why we make sure to be there on your side, for any last minute request, question, fixing. Because seeing you happy is what motivates us everyday.


Taking care of all the final details: complete the snagging, provide all the certifications, warranties and documentation and sign off the project.


Types of loft conversions

Dormer loft conversion

The dormer loft conversion is the most popular type of loft conversion in London. It is a box-shaped structure that replaces one of the slopes of a pitched roof.
A dormer conversion creates a flat-roofed space that allows the installation of full-sized windows and the use of full-height furniture and other appliances.
Dormer loft conversions are often allowed under permitted development.
Councils in London have different rules on the size of dormer loft conversions.

Hip-to-gable loft conversion

A hip-to-gable loft conversion is often used for end-of-terrace or detached properties. The roof slope at the end of the terrace or of the detached house is replaced with a vertical brick wall. It is combined with a dormer conversion to maximise the space.
Hip-to-gable loft conversions in London almost always require planning permission and are more expensive than simple dormer conversions. They are a very good option to increase the space gain, when possible.

Mansard loft conversion

A mansard loft conversion creates a flat roof space, but all four or two of the external walls are gently sloped, instead of being vertical, creating an additional storey.
A mansard loft conversion is more aesthetically pleasant, because of the sloped walls and minimises the visual impact from the street, which is important in densely built areas.
For example, all the buildings on Regent Street in London have mansard loft conversions, so that their street appearance is not impacted.

Other types of loft conversions

L-shaped loft conversions are specifically designed for L-shaped buildings. The shape essentially requires the construction of two dormers that need to be connected in a suitable way.

Roof light loft conversions allow natural light to enter, by installing roof lights in the sloped roof, on both sides.

Boarding and insulating lofts create a habitable space in a loft to be used as storage or simple guest rooms, at a minimum cost

Loft conversions – Planning and permitted development requirements

Under permitted development, you have the right to convert your loft space without the need of planning permission.

For a loft conversion, there are some basic constraints for permitted development:

  1. Volume: the added volume should be less than 40 cubic metres for terraced houses, less than 50 cubic metres for semi-detached and detached
  2. Appearance: the exterior appearance must blend in with the existing house and the neighbourhood
  3. Height: the height of the loft conversion should not exceed the height of the existing ridge
  4. Front dormer: you cannot build front dormers within permitted development
  5. Windows: side facing windows must be fixed and obscured
  6. Balconies and terraces: they are not allowed under permitted development

Rules are stricter in designated areas, where the above conditions might not be sufficient to have the right to permitted development.

Planning permission overview

Planning permission rules vary a lot depending on the council. As general rules, conservation, green belt, archeological and other designated areas have stricter requirements on alterations and building works that are allowed. It is important that you choose professionals who have experience in your council to support your planning permission application.

Average cost

The most frequent question we are asked about loft conversions is: how much does a loft conversion cost? The answer is not one for all. A standard loft conversion in London can have a different cost, depending on the context, the technical and the legal constraints.

Excluding finishes like windows, flooring, sanitaryware, the average cost of a standard loft conversion in London is between £2,000 and £3,000 per sqm.
At this price, the added value to your property is at least double per square metre. For instance, in 2017 in the cheapest London borough the average property value was calculated as £4,000 per sqm.

Our loft conversion projects

Loft conversion with terrace in a Victorian mansion in Chiswick, London

This loft conversion in Chiswick is a mansard and dormer conversion from an existing double pitched roof.
The challenge was to dynamically optimise the structure while the work was in progress. We maximised the headroom installing the new joists in between the existing ceiling joists, instead of placing them on top of the existing.

Loft conversion with terrace in a Victorian mansion in Chiswick, London

One of the challenges in this loft conversion project was that it is located on the border of a conservation area.
In the photo, a view of the terrace before the completion of the loft conversion, when the scaffoldings were still in place.

Loft conversion in a 5-bedroom house in Gants Hill, London

This loft conversion was part of a bigger project that included rear and side two-storey extensions.
In this hip-to-gable plus dormer loft conversion we created one bedroom and one bathroom, optimising the usage of the space by converting a lower section of the roof without any external alteration.

Loft conversion in Forrest Gate, London

In this conversion from pitched roof to dormer we had little head room due to the limited height of the ridge.
We solved the issue lowering the ceiling of the existing top floor by the minimum size to achieve building reg headroom in the loft, minimising the impact on the bedroom underneath.



Chiswick, London

Vincenzo and the team brought the project in on budget and I’m happy to recommend them

Model project


We enjoy working with houseUP as the projects are realised with ease, on time and on budget.


Shoreditch, London

houseUP are real construction professionals and manage their subcontractors well to ensure a good quality of finish.


Waterloo, London

Vincenzo and Mike were always on top of everything, taking care of all the last minute changes and unexpected events that occurred on site.

Get in touch with us for a chat, a free site visit and a free quotation for your loft conversion in London. We can help with dormer, hip-to-gable and mansard loft conversions, including planning and building regs, party wall agreements and more.