Planning a kitchen extension? What to sort out before the builders arrive

Most problems on a kitchen extension don’t start on site. They start months earlier, with a decision that wasn’t made or a form that wasn’t sent. Here is what we’d want any homeowner to have sorted before work begins.

1. Know which permissions you need

There are two separate things here, and people often mix them up:

• Planning permission is about whether you’re allowed to build it at all: size, height and how it looks. Many single-storey rear extensions don’t need a full application because they fall under permitted development.
• Building regulations are about whether it’s built safely and properly: foundations, insulation, drainage, fire safety. An extension always needs building regulations approval.

We’ve written a separate guide on the difference between planning permission and building regulations, including the size limits for permitted development.

2. Talk to your neighbours early

If you’re digging foundations close to a neighbour’s house, or building on or up to a shared wall, the Party Wall Act probably applies. That means serving written notice before work starts: at least one month ahead for digging near their foundations, and two months for work to a shared wall itself.

Most neighbours simply agree. But if you leave it until the week before you start, a one-month notice period becomes a one-month delay. A friendly conversation before the formal notice usually makes the whole thing easier.

3. Decide what the room is for

“A bigger kitchen” is not a brief. Think about how you’ll actually use the space:

• Will you eat in there every day, or is it mainly for cooking?
• Do you want to see the garden from the sink or the table?
• Where will the sofa go, if there is one?
• Do you need a utility area, or space for a second fridge?

These answers decide where the doors, windows, drainage and sockets go. Changing your mind once the walls are up costs time and money.

4. Order the kitchen in good time

The build itself isn’t usually what holds a kitchen extension up. Kitchen units, worktops and bi-fold doors can all have lead times of several weeks. Worktops especially can only be measured once the units are fitted, and templating can add a week or two.

Choose and order the kitchen while the shell is going up, not once it’s finished.

5. Be realistic about timings

For a single-storey extension, the build on site typically takes around eight to twelve weeks once planning and building regulations are sorted. Adding a full new kitchen at the same time can take it closer to sixteen. The weather plays a part early on, when foundations and brickwork are being done.

The design and permissions stage before that can take several months, so if you want it finished by a particular date, start the planning early.

6. Plan how you’ll live through it

The good news is that most of an extension is built outside, so you can usually stay at home. The disruptive part is when the new space is opened up into the house and the kitchen is swapped over. A temporary kitchen in another room, even just a microwave, kettle and fridge, makes those weeks much easier.

What a finished one looks like

If you want to see how this comes together, our kitchen extension project shows the build from the bare shell to the finished room.

If you’re planning something similar in or around Bridgwater, Taunton or Weston-super-Mare, we’re happy to come and look at your space and give you a straight answer on what’s possible.