Our Guide to Home Extensions

With such extreme limits on space in some cities, it’s hardly surprising that so many homeowners choose to build extensions. Adding to existing floor space not only saves on moving costs and disruption, but gives people the flexibility and freedom to create whatever living environment that they want whether an indoor-outdoor area, a kitchen extension, or a place for family members.

Building a successful home extension is by no means a straightforward process. It requires planning and strategising to get it right. There’s a lot to consider, from your goals to your budget, to the practical steps of organising the build itself. Before jumping in, therefore, it’s worth reading up on some of the things you need to consider ahead of time.


Do You Need A Home Extension?

Moving home is expensive. But so too is building a home extension. You need to be 100 per cent sure, therefore, that you’re going to derive value from the project. Having more space might be a nice thing to have, but what is the return for you in terms of quality of life? Is it really worth parting with a five-figure sum that you could use for something else? Be honest with yourself.

Read about Home Extensions

What Practical Considerations Do You Need To Make?

Besides deciding whether an extension offers you and your family value, you also need to think about whether an extension is practical in your location.


Can You Get Insurance?

It’s vital that homeowners get insurance while carrying out building work. Insurance protects you against damage to your property, as well as that of others. When building an extension, it’s possible that construction vehicles could damage surrounding properties, utility connections or supporting walls. Dedicated extension insurance products protect you against these kinds of loss.


Can Your Existing Services Support the Extension?

For instance, do you need to upgrade your existing electrical supply or waterworks?


Can Builders Access the Site?

If you want a home extension, it has to be possible for builders to reach the site to conduct work. There may be no way to get heavy machinery to the rear of your home, for instance.


Do You Have Any Shared Walls?

Special rules apply when building within 3 metres of the boundary of another property, or digging foundations within 6 meters.


What Does the Average Extension Cost?

The actual cost of your extension will depend heavily on size, location, and whether you build one or two stories.

What Planning Permission Do You Need?

You may not need any planning permission for your extension, so long as it falls within the existing “permitted development” rules.

Rule #1: You can extend up to 8 metres from the rear of your property if the extension is single-story. You can extend up to 3 metres if two-story.

Rule #2: Two-story extensions are only classed as permitted developments if they are more than 7 metres from the rear boundary.

Rule #3: You can’t build a single-story extension higher than 4 meters. The height of the roof cannot be higher than that of surrounding properties.

Rule #4: You can’t build extensions forward of the existing building line

Rule #5: You cannot cover more than half of your garden space with an extension

Rule #6: You must make your extension out of the same materials as your current dwelling.


If you plan to deviate from any of these rules, then you’ll need to get planning permission, a process which can take from as little as a few months to as long as two years. If you want to do something radical, then it makes sense to see what other projects have already been granted permission in your local area to get an idea how your project will be received.

How To Get Planning Permission In London - Ebook

Does Your Project Comply With Building Regulations?

Before you start building, you’ll need to send either a Full Plan Submission or Building Notice to the local authority. The Full Plan Submission informs the local authority of your plans, which they then follow up with inspections during the build. The Building Notice proves that you’re complying with building regulations.


Who Will Design Your Extension?

You can, if you wish to, design your extension yourself. Most people, however, use a certified architect – somebody who can ensure that you get something that is not only thoughtfully designed but also fulfils all of the regulatory requirements.

Many of our clients use our services because we offer a different view of their extension. We look at how you live your life and what value this will bring to the quality of your life.  It isn’t just about additional space, but how this space will make a difference to everyday, and often this is not immediately obvious. That’s where an architect can help.

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