Taking on an extension can be nothing short of overwhelming with decisions flying at you from all directions and an enormous pressure for perfection whilst keeping a firm grip on your budget. (I feel stressed just writing it!)

In this article we share some of the top mistakes we've seen and have helped our clients fix. Some may not seem like important decisions to make early on when you're faced with countless others, but believe us, thinking them through early on can make or break your new space and will also avoid expensive mistakes that could frustrate you for years!

At My Bespoke Room, we bridge the gap between your architect’s drawings and an interior space that functions perfectly and makes you happy every time you enter it. Our consultancy service starts from just £195 - find out how it works or to book your free, no-obligation consultation:



1. Not knowing what you'll use the extension for

Black kitchen with brick extension

Image Credit: My Bespoke Room

You might be surprised to hear how common this mistake is! So often people undergo an extension because they feel they need more space in their home but they haven't fully thought through what they need the extra space for and how it will be used.

Trust us - the last thing you want is to have spent all that time and money only to find the same issues lingering. A huge part of an interior designers job is to uncover the true problem and find a creative solution.

If you're tackling it solo, the first step here is to sit down and have an honest conversation with yourself about what the problem is with your home as it is now. Is it that you're all falling over each other during mealtimes? Is it that you want more open space for entertaining? Try to objectively watch how you and your family use the space over a few days and see where the frustrations lie. 

Only once you know the problem can you begin planning the solution!


2. Missing opportunities for storage


White storageImage Credit: My Bespoke Room

Storage might not sound sexy - but neither is clutter!  

Sure, we all tell ourselves that when the new extension is built, we'll be better. We'll put things away after we use them and it will be a mess free zone...But in reality, that lasts just a few weeks and pretty quickly the clutter starts to creep back in.

Rather than fight daily life, prepare for it! As soon as you have your architect's plans hunt down every square inch of potential storage that could be built in.

Trace your steps and think about how you'll enter the room and what you'll do. Will you have your keys in one hand and post in the other? Then factor in a cupboard or shelf for those items to live so they don't end up hanging out on the dining table. 

Remember, there's no such thing as too much storage!


3. Neglecting how you want to feel in the space

Blue kitchen with bifold doors

Image Credit: My Bespoke Room

When you're faced with planning applications, sourcing contractors and costing up budgets it might seem trivial to think about how the finished room needs to 'feel'. But trust us, this is crucial to overall success of the project and there are decisions you need to make early on to achieve it.

Large open plan extensions aren't easy to make 'cosy', but there are clever ways that you can warm up a large space and turn it into the heart of the home you long for. 

If you'd like to dedicate some space to a cosy seating area, then look into whether there's an option to vary the ceiling heights and bring it down in that section. A lower ceiling will instantly make you feel more cocooned within the space.

Paint is a far more affordable yet, equally useful tool for warming up a larger space. Painting one or two walls in a deeper, warmer tone will clearly differentiate that section. Similarly, opting for a deep dark green or blue on your kitchen cabinets can be equally effective.

Wood textures also add instant warmth to a space, so consider incorporating a lovely wood floor throughout your extension to instantly make it feel more 'homely'.


4. Not having enough natural light

Monochrome kitchen

Image Credit: My Bespoke Room

You might have discovered by now that glazing is going to take up a huge chunk of your budget and so you might understandably be keen to ensure you get the most bang for your buck!

Before making any decisions, spend some time watching how the light travels throughout the day.

For example if you know that the light hits a certain wall throughout the day then that’s not going to be the perfect home for your TV. Instead, how about putting a window seat there and making it the perfect little reading/napping spot?

Another example? Rather than installing a piddly little window above the sink in your new kitchen, why not go for a wide window that can be opened fully upwards or fold to the side? Add some outdoor bar stools and you have yourself a summer bar!

bedroom to garden with french doors

Image Credit: My Bespoke Room


5. Having too much natural light!

Post image landscape - 2022-09-28T110949.486

Image credit: My Bespoke Room

'Is there such a thing?' I hear you ask! Well yes, going OTT with the glazing (particularly in south facing rooms) can leave you with a bit of a sauna vibe... not the most comfortable for daily living.

You also might be faced with the goldfish bowl problem in the evenings, when all your neighbours get front row seats to your comings and goings!

Window treatments like blinds or curtains will be a blessing for bifold and sliding doors but they are tricky to get right. This is why we wrote a whole guide on the matter which you can peruse at your leisure here

But if you want to keep your glazing looking contemporary and blind free then you may need to opt for solar control glazing or coating - not something to be factoring in last minute! 


6. Not creating a seamless connection with the existing house

Kitchen/Dining/Living area

Image credit: My Bespoke Room

That's not to say it shouldn't have its own personality or that you should try to hide or apologise for the fact it's not part of the original building... But flow is an important aspect of interior design and there are a number of tricks of the trade that you can implement to create cohesion across your whole home.

An easy option would be to use the same colour paint throughout the whole home - but easy doesn't mean best! In fact it can often look very flat and uninspiring.

Instead, think about a colour 'personality'. For example are you inspired by Miami pastels in different colours? Perhaps you're a lover of highly saturated jewel tones or earthy mid-century greens and oranges? So long as the colours you choose have a similar story or 'feel' to them, you can get creative! 

Flooring is also great for unifying multiple spaces. Use a similar (if not the same) flooring in your existing home to your extension to tie it all together.

Perhaps you love your existing period features like coving or skirting boards. These can also be used to great effect when carried through into the newest addition to your home.


7. Not planning where your furniture will go

designing an extension

Image credit: My Bespoke Room

Furniture is a problem for way down the line right? Wrong! In order for the new space to function exactly how you need it to, you'll need to make sure the furniture will work in it.

For example, if you have a large family you need to accommodate you'll be needing an equally large dining table. If your new kitchen/diner doesn't have the width to accommodate this then you might need to think about clever fitted bench seating along one wall. This way you can tuck your dining table to the side making sure you have enough space to move around during the day and enough seats for everyone in the evening. 

Another key piece of furniture is your sofa. If you don't plan to invest in underfloor heating then make sure you plan really early on where your radiators will be mounted. You'll be left with a headache if you can't find an empty wall to sit your sofa against!

Another tip is to think carefully about how wide you need your bifolding doors to be. It might seem like the dream to have them stretching across the entire wall but in doing so you lose a whole wall to place furniture against. The corner of the wall could be prime position for a comfy armchair looking over the garden so think it through fully before committing. (Not to mention the savings you'd make from having less glazing!)

Speaking of glazing, if you know where the light will fall at different times in the day, you can really take advantage of it with your layout. A particularly sunny patch will be less than ideal for your TV or desk due to the glare on the screen. 


8. Not creating a lighting plan early on

Post image landscape - 2022-09-28T111121.508

Image credit: My Bespoke Room

This is such a crucial point! Without taking the time early on in the planning stage to think about where lighting needs to be installed it will not only impact how it feels but importantly how usable it will be.

The last thing you want is to have to bring an electrician back in to punch holes in your beautifully painted ceiling or walls later on!

In your kitchen space make sure you have enough task lighting to enable you to see clearly when you cook. Similarly, plan where your dining table will be so you can install a pendant above it.

Another tip is to put your lights on different circuits and always make them dimmable. That way you can create a more ambient feel easily and draw attention away from certain aspects of the room. 

Also, don't forget about plug sockets! Make sure you have enough in the right places so you don't have unsightly wires trailing across your floor or across a wall. 


If you want an expert second opinion on your plans our consultancy package could be just what you need. The service starts from just £195 - find out how it works or to book your free, no-obligation consultation:



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