The 6 Home Extension Mistakes I Made the First Time Round — And How Architects Say I Should Put Them Right During Extension 2.0
As I get ready to extend and remodel my house (for the second time), here are the extension mistakes I won't be making this time around
I find it hard to fathom that it is now 10 years since we completed the renovation and extension of our Edwardian cottage — a project that saw us living in what was, essentially, a building site for more than three years, with two children under four years old, scrabbling together funds to get it finished as we went.
Since this time, those angelic little children have turned into teenagers that tower over me, both my husband and I now work from home, plus we have gained a few pets, not to mention more 'stuff'. The extension that once seemed to offer everything we needed from a home is no longer sufficing. Yes, this is, in part, due to the way life has evolved for us, but it is also due, in a very large way, to the renovation mistakes we made when extending the first time round.
Live in a house for a while, and there will always come a time when it becomes obvious that a few tweaks or upgrades are needed. Hopefully, these will be purely cosmetic and not bring about too much in the way of disruption — but in our case it has become clear that it is time to either move house or extend again.
Article continues belowGiven that we have twice sold this place and failed to find anything we liked more, it seems like a new addition, and some pretty extensive remodelling is the best option. Here are the top mistakes we made last time we extended and what we plan on doing differently this time, to help you find the pitfalls in your kitchen extension, before you make them.
1. Not Going Big Enough in the First Place
We could have gone much bigger with our extension without much of an impact on costs — a two-storey L-shaped design would have made better use of the space we have.
Of all the mistakes we made when extending this house, this is the one I regret the most — and the whole reason we are now preparing to don our hard hats once again. Quite simply, we just weren't ambitious enough when it came to the scale of the extension.
We looked at what we needed most at that time – a bigger kitchen, extra bedroom and an upstairs bathroom – rather than what we would need in the future. Ten years on, we need another bedroom and bathroom (or two), a utility room, home office and more storage. The really frustrating part is that to add the extra meterage and even another storey at the time really wouldn't have added to our extension costs that much given that the foundations and roof made up most of the expense anyway.
According to architect Benjamin Wilkes, we are not the only ones playing it too safe. "One of the most common things we see is clients slightly under-reaching — whether that’s in terms of footprint, ceiling height, or how the new space connects to the garden.
"Extensions are a big investment, and small increases in scale or better spatial planning can make a disproportionate difference to how the space feels and functions long-term," continues Benjamin. "It’s also a rare opportunity to completely tune a space to your way of living and your taste — so it’s worth making the most of it."
Ben and Joanna Wilkes, an architect and interior designer, are strong believers in the transformative power of good design. Before founding the company in 2020 Ben spent 12 years working for esteemed London practices like Panter Hudspith Architects and SODA, while Joanna has over a decade’s experience of working alongside renowned interior designers like Christopher Wray, Joanna Wood and Katharine Pooley.
2. Making Snap Decisions on Seemingly Small Details
Everything from lighting positioning to the number of switches and electrical outlets needed more consideration within our own kitchen extension.
We lived on site during the entire project, with our two children who were just 16 months and three years old when we moved in. I'll be honest, things were pretty stressful at times with water pouring in through the roof, bare earth floors, no heating or proper washing facilities. What this meant is that we were desperate to rush towards the finish line and, in our haste, often didn't give enough time or attention to choosing the finer details.
There are now lots of little niggles that are direct results of those rash decisions — electrical outlets in the wrong position, a lack of built-in storage, the badly-positioned bath all being good examples. Yes we can put them right, but it would have been far easier to have just got them spot on at the time.
James Butterworth, extension specialist at Studio J architects, is keen to warn others of making this mistake. "You don’t want to spend a lot of money on a new extension and then, when it is finished, find out some aspects do not work well for how you want to use the space.
"For example, think about where sockets will be needed. Do you have many electrical appliances that need plugging in? Where will the Christmas tree go? And do you want data points to plug a laptop or TV into?" asks James.
"Going into detail during the design phase allows you to really understand how the new spaces will work for you.
If you leave it until the builders have started, it is much more stressful, and often costly too."
James is a qualified architect and has been involved with all of Studio J’s 750+ projects. For that reason, he has a wealth of invaluable knowledge and experience. He says: “Understanding people and their use of buildings is just as important as knowing how to construct buildings.”
3. Failing to Prepare a Proper Schedule of Works
A proper schedule of works would have made it easier to carry out work methodically and reduced the chaos of living on site.
Given that this wasn't my first renovation project and that I spend most of my time writing about extensions and home upgrades, you might assume I have project scheduling down to a fine art. However, practising what you preach is notoriously hard.
Devising a clear, highly-detailed schedule of works, laying out each and every aspect of a project from start to finish, should be a non-negotiable part of any kind of project, be that a kitchen extension or a full remodel. Without one, things can quickly become disjointed and chaotic.
Thanks to our own poor project planning, there were delays on site and additional expenses that could easily have been avoided had we have been a little more organized. Having this kind of detailed to-do list and seeing tasks get ticked off also helps keep you motivated.
4. Forgetting That We Had Drains Running Beneath the Extension
The position of the drains (roughly beneath the base units under the window) meant we needed to unexpectedly apply for a build-over agreement.
There is a tendency to overlook the underground elements of a project – existing foundations, soil types, tree roots and so on – but, whether you are building a single storey extension or something that sits over multiple levels, this is a mistake, particularly when it comes to drains.
"This might not be the most glamorous side of architecture, but drainage is something that is often not thought about until it's too late in the process," picks up James Butterworth. "Building an extension can impact the existing below-ground drainage, which may result in it needing to be moved. This could add a lot of costs to the project.
"In addition, if the drainage is shared with your neighbours, you would likely require the approval of the local water company to make any changes to it," continues James. "This will add extra time and further costs to the project.
Care also needs to be taken with how any new drainage requirements will be connected into existing drains.
For example, do the ground-floor window positions impact where the drainage from the bathroom above goes?
If drainage is thought about early on in the design of an extension, it can reduce delays on site and avoid unexpected extra costs."
In our case, the wall of our kitchen extension fell directly above the existing drains meaning we ended up going out further than was originally planned and we also had to organise a build-over agreement with the local water authority.
5. Failing to Visualize What the New Windows Would Look Like in Position
The heavy glazing bars in the kitchen window look all wrong compared with the slim profile of those used elsewhere — something in complete contrast would have looked better than the mismatched end result.
Choosing the right glazing for an extension is so important if you want the new addition to do justice to the original building, as well as when it comes to ensuring that by adding extra space, you don't end up blocking natural light from existing rooms.
While overall I am happy with the glazing we chose – composite bifold doors for the side extension, conservation rooflights in the sloping section of ceiling for the kitchen extension and the glazed stable door that matches the existing timber casements – the window overlooking the garden from the kitchen was a bad choice. On paper – and even before it was installed – it looked fine, but once in place it became clear that the glazing bars were too chunky compared with the very slimline profiles of the originals. Not only do they look clumsy and make the window appear squat, but they also block light and obscure the view. Changing it was always on my to-do list and now we are extending again I can't wait to wave it farewell.
Benjamin Wilkes has some useful advice that would have come in handy for me when choosing windows. "It’s easy to focus on size alone, but proportion, positioning, and orientation are just as important. We often see glazing that doesn’t quite align with internal elements, or that misses opportunities to frame views or bring in light from the right direction. Just as importantly, large areas of floor-to-ceiling glazing can lead to overheating if not properly considered — so thinking about solar gain, shading, and how the space will perform across the seasons is key."
6. Missing the Chance to Build-in More Storage
Building in storage during the renovation process might not seem like a priority at the time but it makes all the difference later down the line.
We have seriously outgrown our home — in every single way. Not only do we not have enough bathrooms and bedrooms, but it is also in the smaller details that we have come to feel like the house is bursting at the seams.
Upstairs the ceilings are vaulted meaning no loft for storage, there is no garage, and what little built-in storage there is was something of an afterthought and is now stuffed to the brim. Yes we are due a declutter, but had we have had the foresight to get creative with our storage ideas, life would run so much smoother.
My one consolation is that, according to Benjamin Wilkes, this is a common oversight. "People tend to focus on the big visual moves – open-plan layouts and large expanses of glass – but forget about where things actually go. Items like coats, bins, utility space, and even somewhere to put a bag when you walk in often get squeezed out, which can make a finished space harder to live in day-to-day. We always challenge our clients to think through exactly where everything will go – particularly in the kitchen – to ensure the space works as well as it looks."
While we plan on extending to the side of the kitchen and also adding a storey above, the kitchen itself will remain the same size. However, I am keen to avoid making any kitchen remodel mistakes this time around. First to go will be the wooden countertops around the sink, followed swiftly by the stained composite sink and boring white walls.
