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By: grace

Thinking of a Home Extension – Where do I Start?

Extending your home is one of the best ways to add space while also increasing the value of your house. If you don’t want the stress of moving house, not to mention the cost, extending your home to provide the additional space you require can be a great alternative, but you might be wondering where you start, which is why we’ve put together this neat guide to home extensions.

How to plan for your house extension

Wondering how to start planning an extension? Well, the first thing we need to say is that you do need to plan. It would be wonderful if you could just jump in and get started, but before you do that, there are a number of important things to consider, including:

Cost and value 

Unless you have money to burn, before you move ahead with a home extension, it’s important to consider how much it is likely to cost against the value it is likely to add to your home. If an extension is unlikely to add enough value, you may want to reconsider your plans or your budget.

Planning permission

In the UK, some extension projects can be undertaken under your permitted development rights, which means you will not need to seek planning permission before going ahead. This applies if you are:

  • Extending a rear wall by 8m single storey (or 6m if your home is terraced or semi-detached or 3m double storey 
  • Extending no higher 4, single storey or 7m double storey

However, if your development does not meet those regulations, or you are likely to extend across more than 50 per cent of your land, amongst other things, you will need to seek planning permission. So be sure to seek the proper advice before going ahead.

Also check: House Extension Ideas You Can Do Without Planning Permission

Building regs

You will need to comply with all building regs whether planning permission is required for your extension project or not. That means you need to check that all tradespeople conducting work on your property is either fully accredited or able to self-certify.


Your insurance is likely to go up because a bigger home will cost more to rebuild, so you should check with your insurance provider first.


Let your neighbours know your plans as soon as possible., If you can talk to them and discuss any issue they have before they’re hit with a letter from the local planning authority, chances are you’ll be less likely to get into a dispute. You can also iron out issues with party walls and things like that which could affect your project.


If you are a leaseholder, check that your lease entitles you to build a house extension. Normally, you’ll need to agree any work with the freeholder before plans can move ahead.

Does house extension add value to your home?

In most cases, a house extension is likely to add value to your home because space comes at a premium and the more space you have, the better when it comes to selling your property. However, it is always a good idea to consult with a good local estate agent or appraiser before you carry out any extension work because they will be able to give you a better idea of the value that could be added to your home or not.

How to apply for planning permission on house extension

How to apply for planning permission on house extension

If you need to apply for planning permission before your extension can go ahead, you should contact your local planning authority. This is something that you can normally do by getting in touch with your local council. Even if you don’t think you’ll need planning permission for your small house extension, it may be worth contacting them to check.

Basically, you’ll provide them with the entails of your proposed home extension and they’ll make a decision on whether it can go ahead, usually within 8 weeks.

Can you build an extension on a leasehold house?

Yes, in many cases it is possible to build an extension on a leasehold house. However, you will generally need to have permission from the freeholder before you can make any significant changes. As a starting point, you should check the information in your lease agreement to see if that can provide any clarity, but freeholders may agree to let your make structural changes even if they are not explicitly permitted in your agreement, so do contact them either way.

Types of property that can have extensions

Most types of property can be extended in some way including:

  • Bungalows
  • Rear house
  • Ground floor flat
  • Hotels and B&Bs
  • Kitchen extensions
  • Terraced house extensions
  • Cellar and basement extensions

House extension design

Often, the hardest part of a home extension is getting the design right. This is something you can make a bit easier by hiring the right professionals for the job.

Finding a great architect

Depending on the size and scope of your project, having an architect help you on the design front may be a good idea, although there is no legal requirement to do so, and if you can find a decent building firm that specialises in extension, they could be just as good.

Good architects know how to make the most out of available space and they’re great at ensuring home extensions, whether they be kitchen extensions, single storey extensions or wrap around home extensions, are sympathetic to the design of your existing home.

How do you find a good architect?

Ideally, you should ask for recommendations from people you know who have had their own extensions built. If that is not possible, do a local Google search, read reviews, get quotes and go with the most impressive architect you can afford – They usually charge around 15 percent but this may vary between architects and depending on your local area.

How to find a good builder?

Obviously, your builder is the most important part of the home extension equation. They will actually be building the thing, so you need to ensure that they are reliable, trustworthy and up to the job. Again, recommendations are great for this, as are online review sites. Just makes sure that, before you hire a builder, you are completely comfortable with them.

House extension ideas


Not sure what form your extension should take? Some of the most popular extension designs include:

  • Wraparound extensions. These are extensions that cover three or more walls of the property, giving you more space in a larger area of your home.
  • Double storey extensions. Create an extra bedroom or bathroom as well as an additional lounge or kitchen.
  • Kitchen extensions. Create the large kitchen of your dreams and add value to your property.
  • Side extensions. Great for adding space to your kitchen or lounge, as well as creating a sun room or conservatory space for relaxation.
  • Summer rooms.  Somewhere to sit and soak up the rays.
  • Loft or basement conversions. Make the most of the dead space in your home by transforming them into useable bedrooms, offices, bathrooms, or whatever your heart desires.
  • Garage conversion. Turn your garage space into something special and make more room for your family to live in.

Obviously, the number of layouts and extensions designs are almost endless, so it’s always a good idea to talk to your architect or builder about the possibilities if you aren’t sure what kind of home extension design would best fit your home and meet your needs. It may also be worth looking online to see what other people have done so you can take inspiration from their efforts.

How much does house extension cost?

As you might expect, this varies hugely depending on a number of factors, including:

  • Location
  • Scale of build
  • Choice of contractors
  • Type of property
  • Type of extension

However, the average cost of a single storey conservatory extension can start from as little as £1000 per m2, this goes up to £1200 m2 for fully integrated single storey projects and £2500 m2 for higher-end projects.

Of course, you should always seek several quotes before you sign any contracts so that you can get the best price. You should also be sure that you budget for extras like the cost of an architect, and ideally have a contingency fund of around 10 percent of the quoted build project to cover any unexpected expenses.

How long do house extensions take?

Again, this depends on the type of house extension you require, but a basic single storey rear extension measuring 3 metres should take 3-4 months max, and a simple double storey extension could be completed in around 6 months, whereas a loft conversion can be completed in as little as 6-8 weeks.

If you need help with advice on where to start with building your extension contact Create Room Today.

We can help you create the home extension of your dreams. Leaders in the field, and fully signed up members of The Federation of Master Builders, whether you want a garage conversion, loft extension or garden room, we’ve got you covered, so what not call us on  01277 363030 or 0800 622 6722, or drop us an email at