Do I Need An Architect For An Extension?

Building extensions come in many shapes and sizes, and costs vary enormously. Still, when the project is well designed and managed, an extension can make a big difference to your living space and save the need for costly relocations.

You may know people who have designed and built their home extension or got their builder to do the design work, saving the cost of an architect. The straightforward answer to the question ‘Do I need an architect for a simple building extension’ is no – there are alternatives that might work for you. But when making this decision, you must consider cost and weigh up the value an architect will bring in terms of skill, experience and know-how.

Many a DIY project has spiralled way over budget for a sound plan and strong project management. So let’s evaluate the benefits of hiring an architect to get your dream extension off the ground.

The Role Of The Architect

An architect is instrumental in designing and drawing the plans for your extension. They will work collaboratively with you and help to ensure that your dream extension is logistically viable. What’s more, they will draw up plans which will be essential in allowing builders to give you a fair and accurate quote for the extension. Without this, builders will likely work from estimations based on similar jobs they have carried out in the past but may wind up overcharging through no fault of their own.

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An architect can work to your budget. They can build opportunities to make savings into your design plans. They can also help you to realise where it’s best to concentrate your budget and where concessions can be made. Many will also have good relationships with reputable builders. They can help you make an informed decision about who has the skills necessary to carry out the work to a high standard within your allotted budget.

The more comprehensive an architect’s designs, the more sure you can bet that you’ll be free of unpleasant surprises, disputes and unexpected costs throughout the build. It also helps to ensure that you know exactly what you’ll be getting even before work begins. Home Builders has the best range of dual occupancy builder services to help you create your dream house.

The Architect And Planning Permission

Some types of the extension will require planning permission from your local council. An architect will have the knowledge and experience to determine whether your project will require planning permission. In cases where planning permission is necessary, an architect can help to ensure that your plan stands every chance of having planning permission granted.

They know precisely how complicated the process of making a planning permission application can be and will endeavour to make it as easy as possible for you. Even nascent architects will be highly conversant with the application procedure and ensure that your project’s plans match your local council’s exact policies.

The Advantages Of Using An Architect

An architect is a qualified professional whose job is to help you plan, design, and manage a project. It is important to remember you do not need to hire an architect for the entire project; they could be as involved as you want them to be. As we mention, they are not legally required but can be very helpful in the following situations: 

  • If you don’t have a clear idea of what you want, an architect could push the design of your extension into unknown territory as well as optimise the space you already have. They are trained to think outside the box and could design something you couldn’t think of yourself.
  • Architects are experts at enhancing interesting design features without doing a pastiche if your house is listed or somewhat historically interesting. They will know the best ways to get sensitive projects through planning, especially if they are already familiar with your local council.
  • If your project requires several different professionals for technical reasons – for example, if you’re planning to dig a basement – then architects are excellent at putting together all the information and managing building teams. Hiring an architect can save you the trouble of trying to put together two different engineers’ drawings.
  • If you’re hoping to build using sustainable methods, architects who specialise in green architecture will know how to push your project further and use the best materials for your extension. 

Do I Need An Architect For A Simple Building Extension?

The magic

Good design is hard to define – you know it when you see it. And while you might want nothing more than a simple box added to the back of your house, an architect will have the skill to design that box, both internally and externally, for genuine aesthetic and functional satisfaction.

They will consider how you intend to use the space, what it needs in terms of utilities, heating and light, how it blends in with the rest of the house and garden, access and any other features that need to work within the overall design.

In addition to the inspiration they bring to the design, an architect will bring the plans to life with 3D CAD renderings, making it much easier for you to visualise the finished extension and make any changes before any ground is broken. And a proper architect’s plan will enable you to obtain precise, like-for-like quotes from builders and make sure they stick to the plan throughout the project. This can save costly delays and disputes.

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An architect who regularly works on extensions will have a wealth of experience of the potential pitfalls and key considerations involved. They will be able to give you accurate estimates of how long the project is likely to take, including the preliminaries like obtaining planning permission and building regulations; they will advise you where you can save money and where it’s worth spending a bit more.

Their knowledge of the latest building materials will enable them to specify items you or your builder might not know about, e.g. items that add interest or functionality or save money. And they will be attuned to spotting potential snags well in advance, such as acoustic and fire regulations and party wall issues, which could otherwise force an expensive change of direction during the build if not identified in time.


Hold-ups to extension projects are often due to process disputes, such as planning permission, building regs, party wall agreements and building contracts. Architects are well versed in all these processes and will be able to advise you of your responsibilities. They can help you speed up the process, too, for example, by drawing up plans that they know will comply with local planning requirements.

The local knowledge of a local architect can be invaluable. They will be aware of the issues that tend to arise with similar projects in your area, and their familiarity with local contractors will help select the best builder for the job at the best price.

If you feel uneasy about leaving the project management to your builder or managing it yourself, your architect will be able to handle the project on-site too. This third party buffer between you and your builder can help to allay misunderstandings and disputes and keep the project running on time and budget.

On its face, hiring an architect for a simple extension can look like an unnecessary additional cost. However, when you weigh up the benefits an architect brings to any construction project – and count the cost of all the things that can go wrong if you go ahead without one – the argument for involving an architect goes way beyond the build’s scale. In addition to the peace of mind, punctuality and cost-efficiency benefits, you will end up with an extension that looks fantastic and gives you joy every time you look at it, inside or out.


The education and background of an architect versus a draftsman are different.

Architects have a degree and are required to have a minimum of 2 years of industry experience. However, before they can legally call themselves an architect, they must be registered with their local state Architects’ Registration Board. The training covers a broad range of building design from homes and commercial projects to infrastructures such as bridges and tunnels.

A draftsman may be tertiary-educated, typically with a 2-year advanced diploma and call themselves a building designer. The drawings produced by a building designer are used to obtain planning and building permits and enable builders to tender for construction. If a draftsman is not tertiary qualified, then they cannot be included on a building permit.

In Victoria, building designers are required by the Victorian Building Act (1993) to be registered with the Victorian Building Authority under the category of Draftsperson, Class of Building Design (Architectural). Provided a building designer is registered, they can have their name listed on the building permit. Naturally, they should have professional indemnity insurance also. If a draftsman is not tertiary qualified, then they cannot be included on a building permit.Finding the right duplex build is an important decision. Check out our range of the best home design constructions at Home Builders. 

Top Alternatives

Architectural Technologist

These professionals apply the science of architecture, specialising in buildings’ technological aspects, including design and construction methods. They work alongside architects and therefore have an understanding of space, materials and aesthetics. Add these aspects together, and they’re well qualified to design individual homes.

As they’re not full-blown architects, they tend to charge less and offer tremendous value for money. This can be especially true when it comes to contemporary, energy-efficient buildings, as many architectural technologists are qualified to design to Passivhaus standards.

Architectural technicians possess similar qualifications to technologists, although they cannot work as sole practitioner. Check out the Charted Institute of Architectural Technologists’ website to find members working in your area.

Package Company

If you were looking to build an entire house, then a packaging company may have been an option you were thinking about. The many package house suppliers in the market rely on great design to sell their products. The basic idea is they come up with a scheme at little or no cost, using their in-house architects and designers. You then fall in love with the concept and commission them to take the project through planning, Building Regulations, and some construction works.

The catch is that they own the design, so if you want to use it, you will be obliged to sign up for their timber frame or materials package, and that’s where they make their money. The plans, therefore, become the sprat to catch the mackerel, so these companies need to have exceptional architects and designers on board.

Using a packaging company is a popular and sensible route into self-build homes, especially for first-timers, as you’ll have access to their support through the project.


Anyone who is not formally qualified falls into this generic category. In effect, anybody can call themselves a designer, so it becomes all the more important to do your homework. The key things to look for are examples of previous work, which must be followed up with client references to prove competency. You should also ensure you see proof of professional indemnity insurance.

These designers have a role to play. Many concentrates on small-scale projects such as simple extensions and cosmetic remodelling, where the costs associated with a fully qualified architect are sometimes not justified. This category would fall into the design and build companies that offer stock plans and the resources to build them. Costs are relatively easy to control, but don’t expect state-of-the-art architecture.

DIY Design

Lastly, you could have a go yourself. Core versions of 3D design software packages such as Sketchup are free to download and, with the help of web tutorials, give everyone the chance to draw up their scheme. 

Getting a self-drawn design through the planning process is uncommon. Still, the critical question is whether the scheme has considered if it can be built economically to meet the Building Regulations. 

At this stage, DIY designs can come unstuck where space has been designed, but no thought given to the structural support or the aesthetics of the rooms. It’s what you don’t know that you don’t know that gets you into trouble and can potentially end up costing you more in construction costs than paying for someone to design it economically in the first place. Many architects and designers will be familiar with the clients who call up having obtained planning permission for their drawings but no idea how to build them.

If you think this is a step too far for you, another approach would be to use the software to mock up ideas that can inform your brief to an architect or house designer. The more information you can supply will help ensure you are both on the same page from the outset.

When Won’t I Need An Architect?

It’s important to note that it’s never a legal requirement to have an architect. The decision is up to you. Some people successfully carry out major works and renovations, including extensions, without an architect’s aid. In contrast, others employ an architect even for something as relatively straightforward as renovating a bathroom or kitchen.

If you have an obvious and specific idea of what you want and are in touch with a trusted builder who knows exactly what it takes to bring your project to life, an architect is somewhat less necessary. However, if you only have a rough idea of what you want and aren’t sure if it’s practically viable, an architect becomes much more necessary.

Remember that just because you don’t legally need one doesn’t necessarily mean that it’s not a good idea to have one. Even if you don’t require planning

But Aren’t Architects Expensive?

If you’ve decided that your extension requires an architect, but your resources are limited, don’t panic. The consensus is that hiring an architect is an inherently expensive endeavour, but this is not always the case. It’s worth noting that, like many service providers, you’ll find that there’s a great deal of variation in architects’ fees. You can save a great deal by opting for an architect who is just starting in their career. They may have the skill and know-how you need for a beautiful extension… They may charge a lot less. At Home Builders, we have the best dual occupancy selection to make your house a dream come true.

Ultimately, it’s your call. For complex, cutting-edge designs, highly energy-efficient homes or where you want to extract the maximum from a complex plot, hiring an architect will be money well spent. But if you are building a generic four-sided box extension with a flat roof, it may be a waste of your budget, as there are designers who can do just as good a job for a fraction of the cost at that level.

The trick, as always, is to shop around to find somebody who is on the same wavelength as you, who has a portfolio of work that inspires you and who understands your budgetary constraints. Letters after someone’s name mean nothing without ticking those three boxes!

An architect is an invaluable part of the planning process and can save you time, effort and money in the long term, despite the upfront cost that they represent. If your project requires planning and planning permission, their plans can be invaluable in helping the project run smoothly without opposition. Even in situations where planning is not legally required, an architect can still help the build go more smoothly and cost-effectively.

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