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How to get your extension right!

17 July 19 Author:Michelle Gaffaney

So you have decided you want to extend your home and where exactly you want the extension, but how do you now get the perfect design for the space you are about to get? Here is a short guide to help:

Any sort of home improvement can be stressful. However, I am sure we can all agree there are fun bits too, such as getting to design  just how your new space is going to be. By having a good design process in place it is very likely you will get the finish you dreamed of. However, this doesn’t mean it’s always the smoothest of processes, sometimes the experience can leave you feeling fraught, out of pocket, and disappointed with the results. Here are some ways to help you avoid feeling like this:

Do you need a designer?

There is no doubt that at some point in the project you are going to need some help with your design, but this doesn’t necessarily need to be the whole way through the project, and there are alternative options to using an architect that could save you some money. As with all extensions there will be limitations to what you can do due issues such as space, your houses original design, and money. It is a good idea to have a structural engineer go over your plans with you so they can advise as to whether your sizing’s etc work, and whether you need to make any adaptations to your design. It would also be a benefit to get an experienced house designer in at this point, they can help solve particular problems that builders may not be able to, and give your design that wow factor you may desire.

House designers have a knack of being able to make even the most ordinary shaped extensions look and feel amazing. From window placement, to interior design, to the materials used on the exterior, a house designer will be able to show you some amazing ways to create a beautiful space. They generally also have some great tips and experience of how you can save yourself some money at the same time if budget is a concern.

What are your options?

If you decide you want to go to with an architect pop along online and search for the Royal Institute of British Architects (RIBA), they have a list of many architects in the country to help get you started with your search. Just remember that even though they are qualified to do architectural work there is more needed for your project, such as having the ability resolve difficult design issues, and being able to engage with the project, the other tradespeople on the team, and yourself.

However, you could also just use an experienced house designer that is not an architect. Make sure that the one you choose is recommended by others and not just the cheapest. You can use a structural engineer alongside the house designer if needs be. There are various options available to you so think carefully what way will work best for your design and your budget.

The best ways to find a designer:

Pop along to, there you can find a database you can search for architects. They also have a bespoke service for matching referrals for homeowners. For designers that aren’t on the RIBA website but still offer many of the same services as an architect, such as architectural technologists, try

Obviously, for designers that are unaffiliated it can be harder so do your research! Recommendations are key!

Talking to local builders is also an option they will have worked with and know who would be worth getting in touch with.

Finally, you could look at the designers that have submitted plans in for planning permission and see if you like any of their designs.

What does a designer do?

A designer will look at the initial idea and tell you if its feasible, they will co-ordinate structural drawings, do a cost analysis, and give construction advice to get the design through planning and building control.

You can generally expect the following from a designer working on an extension:

  • Producing initial drawings to ensure they are getting your ideas right
  • Submission of plans to correct authorities
  • Production of final plans, not only for building control but also to get some quotes off builders

For some designers this is where their involvement will end. however, some designers, such as ourselves, will also project manage the build as well. Just make sure when you pick your designer that if you want one that will project manage the build, that they have the right experience and knowledge to do so. Remember, your house designer may not be able to do everything you need for your extension! For instance, if you have certain planning issues a specialist planning consultant would be better purpose. Use your designers strengths alongside a team of experts in other areas, this way you will have more chance of achieving exactly what you want.

Decisions, Decisions!

Now you need to shortlist a designer from the list of names you have researched and put together. Arrange to meet your chosen designer to discuss your project with them (some may offer a free consultation, some do not). While your with them see how at ease you feel with them, do you feel they understand what you want to achieve? That they have the sufficient skills needed? Also look at previous projects they have done, do you like their work? Do they listen to you, but also offer advice if they feel they have an idea that could work better? Find out what they do well and what they can bring to the project that others couldn’t. Another important factor to consider is how long they expect the process to take, and what do they charge?


Generally designers now tend to work on a fixed-fee basis, this helps makes costs more transparent. For a larger extension design an average fee would be £7000-£15,000, obviously this could go up for a bigger or more luxurious project. Anything below £5000 would mean the designer wouldn’t be able to afford to put the design hours in to ensure the design is at its best. However, it may be that you don’t need much design work, if this is the case you would be looking more around the £2000-£5000 mark.

What does the designer need from you?

The more information you give your designer the better the outcome of the project. Initially at the briefing stage, you should give them;

  • Basic requirement in terms of rooms needed
  • What you intend to use the room for
  • Some examples of spaces and designs you like and don’t like
  • Your budget
  • Other key information such as whether you want lots of natural light, or the space to be energy efficient etc
  • Also give them a list of experiences you hope to enjoy in the new space, for example, having a coffee in the morning sun overlooking the garden/fields

You can then use your experience list once your initial plans are drawn up, to see if the space designed would work with those experiences you pictured.

Revising the design

Do not expect the first draw up to be perfect, it is a hard task for someone to put exactly what is in your head onto paper. Also you should always take a few days to look over the plans each time anyway, because you can’t change it once it is built! So make sure you take your time and get it right on paper first. Be open and clear with your designer on what exactly isn’t right and how you would like it to be, and offer any possible solutions too.

End of the relationship!

The relationship between yourself and a designer can end in various ways, sometimes it may come to an end before the project has even begun, if satisfactory plans cannot be agreed by all. Sometimes it can get to the point a fresh set of eyes and ideas are needed to get past certain project problems. This may mean getting a new designer, or maybe getting more then one designer on board. If you have agreed to pay a fee at each stage this will help, as it means a less of a hit if you do decide to let a designer go. Hopefully though because you spent time researching and getting to know the designer first there should be no issues and they will be by your side working through the design with you, until a point you don’t need them anymore.


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Look out for our next blog coming soon on planning permission!

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Michelle Gaffaney
Michelle Gaffaney - Architectural Director
With a wealth of experience working on a range of projects, Michelle Gaffaney has a passion for design and strong relationships with her clients. Connect with Michelle on LinkedIn