Garden extension with bifold doors

Most people would love to have the opportunity to create more room in their home. An extension creates a space between the garden and the house which both adds value to your house and your life.

Whilst the idea of an extension may be appealing, the prospect of how it will actually be implemented may be daunting.

So, we’ve made this ultimate guide to help you through the process of planning and designing your extension with bi-folds, from costing through to choosing the materials.

Starting your plan

Before any action is taken, there are a few important points that you need to consider:

Your budget

You should not only think about the cost of materials, size and labour, but also factor in any finishing touches.

Generally speaking once you have established how much you can spend, you can try to get the biggest extension your budget and house allows – this will add most value to your home.

Amount of outside space

The next step is to assess how big your garden is. If the extension is too large, and looks out if place, it may not look too good and actually devalue your home. You want to get the balance just right.

Amount of internal space

Would you be willing to rework your kitchen or living room? If you are, you could create an even larger amount of open space.


Consider how many bi-fold doors you need. If you’re extension is larger you are going to need to invest in more to maximise the amount of light that enters your home. More doors means increased light, which will benefit your home considerably. Check out our guide on how to measure the opening for your bi-fold doors.

How much will it cost?

Don’t forget that there are more costs than just the extensions itself. You’ll need to account for the contractors, architects, flooring, doors and windows, so remember to work these in to the budget.

For a rough guide, the average cost for an extension which is built on the rear of a building is between £150 – £250 per square foot (for the materials and builders only).

Your extension can add 12% value to your home, so it’s definitely worth getting if you do have the budget.

Top tip: Allow a 10% contingency fund for any unforeseen circumstances. In an ideal world you won’t need this, but it’s always best to be prepared.

Hiring an architect

Sometimes it’s best to leave things to the professionals.

An architect will help you with the crucial design stage. They will know if certain materials will work, the perfect size for the extension, and will help with the planning process so that it’s more likely to be accepted. An architect will also already have relationships with builders, plasterers and electricians, so you won’t have to deal with the hassle yourself.

So, take a browse through your local directories to see if you can find a local one which would suit you. You can search for qualified architects on the Royal Institute of Architects website. Ask for a quote from a few and assess who you would most like to work with.

Planning permission

You need to make sure your extension matches the permitted development rights. All extensions need to be checked for planning permission, but not all of them are going to need it. You can apply for a certificate of lawful development from your authority.

They are a few limits and conditions to your extension, including regulations like ‘no extension should be higher than the highest part of the roof of your home’. To see the government’s full list of criteria, visit Government’s Planning Portal Website.

It only costs £150 to apply for planning permission, which isn’t too much in the great scheme of things. However, this can be a lengthy and long process. It’s best to apply as soon as possible if you want to get your development going.

If you are building near, or on, your neighbour’s boundary then you will also need to comply with the Party Wall Act (England and Wales) 1996. So it’s worth also talking through your plans with your neighbours first – maybe take them some goodies around when you do!

Your chosen material(s)

You need to decide what vibe you are going with for your extension. You may choose different materials depending on whether you want it to look modern or more classic.

If you want the extension to match your house, then it’s worth getting the same type of material. But if you’re looking to style up your house a little more, then feel free to explore other ideas!

You could choose brick, steel, timber, stone, or even bamboo for the main structure. This is where the help and opinion of an architect may be useful.

One of the most popular materials used for extensions is glass. This material is implemented through the use of bi fold doors.

Bi-folds for your extension

An extension using bi-fold doors will maximise the value of your home to another level.

  • They make your extension a link between the indoors and outdoors
  • Can be opened to make the space even larger
  • They bring more light into your home
  • Save money on utility bills – even in Winter
  • Thermally efficient so keep your house warm/cool

If you’re planning an extension with bi-folds then feel free to get in contact with us – we’re more than happy to help.