How Much Do Architects Charge ?

Buying a house is an expensive investment. Further, an extension is the second biggest financial investment you will be undertaking after buying your home.

However, this should not discourage you from having an extension project since extensions not only add tremendous value to your home but also saves you from moving in an unstable and complex housing market.


When you got help from an architectural firm while you are building your extension, there are several stages the project involves, and these stages cost differently. This fact is crucial for your extension projects’ budget since many firms attract customers with low initial prices, however, these prices go up till the end of the project.

As Studio20 Architects, we care deeply about being transparent about the fees of our services, as well as helping you avoid getting scammed or tricked elsewhere. Therefore, the Studio20 Architects team prepared a guide regarding how much architects charge in projects.

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The cost of traditional architecture practices

In the traditional architecture practices, the forecast that the industry suggests is to calculate the cost of your architect based upon a percentage of your total budget. The traditional architecture practices costs on average between 5 to 10% of your budget.

To illustrate, if you are about to build a regular rear extension in London, your rear extension project will cost around £75,000 in total, and when you get traditional practices from your architect, it will cost 5 to 10% of your budget, which is between £3750 and £7500.

However, if you are about to build an extension project for the first time, it might be challenging to estimate these costs explicitly. For example, if you have not decided on your budget yet, how can you possibly predict 10% of it?

Therefore, as Studio20 Architects, we highly recommend you to get a consultation in this case. The Studio20 Architects team will help you review and revise the ideas you have, and to arrange project budgeting.


What’s included in this price?

For 5 to 10% of your budget, you may expect the services below:

A planning package

Existing drawings of your home

Technical drawings covering building regulations

Architectural drawings

Unlikely to be covered: 3D models, project management services

If you expect from your architect to manage the project too, usually, you might expect to be paying from 10% to 15% of the total contract sum as a price.

If you have decided to pay the price by the hour, you might expect the price to cost in the range of £50 - £90, depending on the scale of your project and your demands. Therefore, architectural costs may rapidly get piled.

What can affect prices?

The cost of architecture practices might be influenced by a variety of factors such as:

Size of the project

Location of the project (London is one of the costly ones)

The prestige that is connected with practice and/or demand

Your architect might have a prestigious award (not necessarily for the residential projects), therefore this situation might cause him/her to demand high-end fees.

Moreover, your architect might have a reputation in the field you want to work on with her/him, and if she/he is part of the RIBA (The Royal Institute of British Architects), also the prices might go up.

Our team at Studio20 Architects includes RIBA architects and architects who have a proven track record delivering excellent extension projects.

Building Garden

The complexity of the project

In the end, while choosing your architecture practice, you will get the best price when you put practical experience first, over fame.

Transforming your home with Studio 20 Architects

Studio 20 Architects only aims to provide the services that you actually need. Consequently, our team focuses on ensuring that you only pay what you need.

Therefore, we will assist you to find the best fit services for your extension project whether you need a light professional touch or you need expert guidance throughout.

Studio 20 Architects specializes not only in architectural work but also in everything that reveals your property’s potential. These services are measured surveys, creating a proposed design, planning, building regulations package, new builds, and connect.

Measured Surveys

In your home development journey, especially in extension projects, one of the most significant questions you may ask your architect is whether your extension project needs a measured survey.

In this service, Studio 20 Architects surveyors will visit your house to note the existing state and measurements of your house and photograph your house’s every aspect and dimension in order for our designers to visualize your house accurately.

After taking the measurements, our architects will turn these images and measurements into existing drawings. You can find such examples on our Instagram account highlighted as drawings, and these existing drawings might differ according to your project type.

It might include elevations, floor plans, roof plans, sections, and site plans, and all of these drawings must be done since they are requirements for both your local planning authority and our designers and architects involved in the project.

Studio 20 Architects provides a remote-option as well for the clients who would prefer to avoid home visits or cut the costs.


Proposed Design

The proposed design is also another important step in homebuilding projects. When creating a proposed design, the aim is for you and your designer to clarify how you want to see your project when done.

The proposed design includes the amount of glazing you may want to include in the project, envisioning your future layout and exteriors.

Proposed designs concentrate mostly on the aesthetics of your property, however, proposed designs are also used during getting the planning approval from your local authority since they are one of the requirements.


During the planning stage in your extension project, Studio 20 Architects will assist you to apply for one of the two permissions: planning permission or a lawful development certificate.

If your project is considered under the permitted development rights, then the lawful development certificate is suggested. The lawful development certificate is ensuring the local authority and future buyers that your build was legal at the point of construction.

On the other hand, if your project does not consider under permitted development rights, then you are legally obliged to acquire planning permission. In the planning permission process, your local authority will assess your proposed design.

The need for either of the planning permission or the lawful development certificate, Studio 20 Architects will assist your project with a full planning package that includes: proposed designs, your existing drawings, and the verifying information required by your planning authority.

Normally, planning applications take 8 weeks to reach a decision and during this time period, Studio 20 Architects’ planning agents will be in touch with your local council, and Studio 20 Architects’ planning agents will represent you in the local council.

Find out more about planning permission and lawful development right here!


Building Regulations

When the planning permission was granted, you should consider a building regulations package.

This stage will help you get approval from building control and will assist contractors to provide explicit and accurate quotes in order to create a better standard of the build for your extension project.

Studio 20 Architects may combine the drawings that are used for the planning applications with your building regulations package. Not only our team’s in-detail technical drawings will shape your extension project, but also the recommendations from the professionals and advisors in our team will assist you regarding the next steps you have to follow for the construction.

Our team will investigate the other professionals who will be involved in the construction phase such as party wall surveyors and structural engineers.

Find out about our Building Regulations guide here.

New Builds

When building a house from scratch, whether you are a seasoned developer or a first-timer looking to create their dream home, it requires a terrific work.

Studio 20 Architects unites the services that a new homeowner might need under one roof and the package will be customized according to your project.


Connect is one of our complimentary services in which the Studio20 Architects team will source the best builders and professionals in your area in order to be sure that your building journey is in safe and trustworthy hands.

Studio20 Architects will assist you to assess the quotes from professionals and will help with appointing your contractors.