Do You Need the Biggest Possible Extension?

Not always.
 

A larger extension may increase the build cost, reduce the garden and create a room that is harder to furnish.
 

Sometimes a smaller extension combined with better internal planning will create a more attractive and practical result.
 

Ask yourself:
 

• how much space do you actually need?

• how much garden do you want to retain?

• will the room still feel comfortable and balanced?

• will natural light reach the centre of the house?

• can the furniture be arranged properly?

• is the extension proportionate to the original property?

• will the additional cost deliver enough value?
   

Good design is about quality of space, not simply quantity.

 

Think About Natural Light

Natural light is one of the most important parts of extension design.
 

A new extension can create a brighter home, but it can also make the middle of the original house darker if the layout is not considered carefully.
 

Options may include:
 

• rooflights;

• roof lanterns;

• partly glazed roofs;

• sliding doors;

• bifold doors;

• fixed glazed panels;

• steel-look doors;

• internal glazed doors;

• clerestory windows; and

• picture windows.
   

The best solution depends on the property, orientation, garden and internal layout.

 

Think About the Garden

The relationship between the extension and the garden can affect the success of the design.
 

Consider:
 

• where the patio will sit;

• whether the internal and external floor levels should align;

• where the doors should open;

• where garden furniture will be positioned;

• whether privacy is important;

• whether trees affect the outlook;

• whether the garden is sunny or shaded;

• how much garden space you want to retain; and

• how the extension will look from outside.
   

A good extension should improve the garden relationship without overwhelming the outdoor space.

 

Think About Your Budget Early

Before you commit to a design, set a realistic overall budget.
 

Your budget may need to cover:
 

• design drawings;

• planning applications;

• Building Regulations drawings;

• structural calculations;

• Building Control charges;

• party-wall matters;

• construction;

• glazing;

• kitchens;

• bathrooms;

• flooring;

• decorating;

• landscaping;

• VAT;

• professional fees;

• and a contingency allowance.
   

A clear budget does not mean you need to choose the cheapest option.
 

It helps you understand where your money will make the biggest difference.

 

Planning Permission or Permitted Development?

Some extensions may fall within permitted-development rules, while others require a planning application.
 

The correct route depends on the property and the proposal.
 

Important factors can include:
 

• the depth of the extension;

• the height;

• whether it is single-storey or double-storey;

• the position of the extension;

• previous additions;

• the type of property;

• whether the property is listed;

• whether the property is within a conservation area;

• whether local restrictions apply; and

• the effect on neighbouring homes.
   

Do not assume that your extension will automatically be permitted because a neighbour has completed similar work.
 

Every property should be checked properly.

 

Planning Permission and Building Regulations Are Different

Planning permission considers whether the extension is acceptable in principle.
 

Building Regulations deal with how the extension is designed and constructed, including foundations, structure, insulation, drainage, ventilation and fire safety.
 

Most extensions need Building Regulations approval even where planning permission is not required.
 

You may also need structural calculations, particularly where walls are being removed or large openings are proposed.

 

Speak to Professionals Before You Make Expensive Decisions

At the early stage, the most useful advice may come from:
 

• architectural designers;

• planning consultants;

• structural engineers;

• builders;

• kitchen designers;

• glazing specialists;

• Building Control professionals;

• party-wall surveyors; and

• project managers.
   

You do not necessarily need to appoint every professional immediately.
 

The first step is to understand the likely route, the design options and the order in which decisions should be made.

 

Create a Simple Wish List

Before speaking to a designer or builder, write down:
 

What you definitely need

​

For example:

​

• a larger kitchen;

• a dining area;

• a utility room;

• a downstairs WC;

• better garden access;

• an extra bedroom;

• a home office; or

• more storage.

​

What would be nice to have

​

For example:

​

• a kitchen island;

• a roof lantern;

• sliding doors;

• a pantry;

• a shower room;

• underfloor heating;

• built-in storage;

• a separate snug; or

• a garden-facing seating area.

​

What you want to avoid

​

For example:

​

• losing too much garden;

• an overly dark internal room;

• a complicated planning application;

• an unrealistic build cost;

• too much disruption;

• or a layout that feels too open.

​

This will help you focus on the design decisions that matter most.

​

​

Take Time Before You Commit

The early stage of an extension project is your opportunity to explore ideas and make better decisions.

​

Once building work begins, changes become more difficult and more expensive.

​

Before moving forward, make sure you understand:

​

• the type of extension that suits your home;

• the space you actually need;

• the likely planning route;

• the professional services required;

• the broad budget;

• the effect on the garden;

• the importance of natural light; and

• the next practical steps.

​

A well-considered design can help you create an extension that feels like a natural and valuable part of your home.

​

​

Still exploring your options?

Tell us about your property, the space you need and the ideas you are considering.

​

Where appropriate, APN Extensions may introduce you to relevant independent professionals, consultants and service providers who can help you understand the possibilities and plan the next steps.

​

You are under no obligation to appoint any provider introduced through APN.