London House Extension Specialists

Getting Started With House Extensions

Our no-nonsense guide will help you understand the planning process to get you started on adding an extension to your home.

To move or to improve?

A home extension can be a very effective way to make an existing house a better place to live in. What’s more, it can add significant value to a property – a loft conversion has been shown to add as much as 10 percent to the value of a house.

Homeowners must weigh these benefits against the mounting costs involved in selling a home and moving elsewhere – things like stamp duty and conveyancing. There has been a sharp increase in homeowners choosing to add to their existing home – it reached 15 percent in 2018, having been just 3 percent only 5 years earlier.

house extensions

Securing a planning application for an extension

For new buildings and major alterations to a building’s structure or purpose, you will almost certainly need planning permission. There are many stories of the challenges that you face when seeking planning permission, but the reality is that around 9 in 10 applications are approved by local authorities.

The decisions about whether to approve or refuse planning projects are made by local planning authorities. In some cases, people must apply by getting in touch with a private Building Control Body (BCB). This involves submitting an application via a private approved inspector.

Once you’ve managed to secure the appropriate approval for your plans, you should check with your building company and architect to ensure they are in agreement with the formal arrangement you have agreed. If adjustments need to be made after construction work has already begun, you could find that things get messy quite quickly.

How to design your extension

When designing an extension for your property, you must decide whether to hire an architect or do it yourself. You could also opt to work with a build and design company. Unless you have plenty of experience in renovating properties, it’s advisable to get the help of the professionals to ensure this stage is done right.

Finding a good architect and builders

The foundation of a quality extension design is to find a great architect to draw up the plans. This requires a good amount of research, looking at customer reviews and recommendations to sort the wheat from the chaff. It’s important to do your homework, even if you are designing the extension yourself, as you will probably still need a designer or draftsperson to professionally draw up your plans for the purposes of getting planning approval.

Further down the line, it is equally important to find builders you can rely on to get the work done well. One important skill they should have is problem-solving, since this could save you money on labour if something goes wrong at any point in the process. A good place to start is a website like, but word-of-mouth reviews from people with first-hand experience of a contractor’s work can be invaluable.

How extension affect home insurance

Your existing buildings and contents insurance policies could be affected by having works done at your home. They could even be invalidated by it.

  • Buildings insurance: This covers the fittings and fixtures in your home. Check with your policy provider before undergoing any structural changes to the property to make sure you will still be covered after adding an extension. They may require you to amend your policy, depending on the nature of the work being undertaken.
  • Contents insurance: While building work is being carried out on your property, the risk of theft or damage to your possessions may increase. Doors will be left open or removed, and there will be many more people coming in and out of the property whilst builders are working. Have a look at your policy to check if your valuable possessions will still be covered by the existing contents insurance.

If you find that your existing home insurance will not cover you during or after an extension, it may be wise to shop around for some new cover. If early exit fees apply on your current policy, you may want to wait until it expires before you start the project. In some cases, it may be necessary to get specialist renovation insurance.

Even if you are confident your existing policy will still cover you during and after the extension, it is still wise to take some precautions to avoid your home being damaged. Make a plan to prevent dust or damage from affecting existing fixtures and fittings – tarpauling sheets can be excellent at protecting valuable furniture.

Funding the project

Whether your sights are set on a bigger kitchen, a garage or any other type of extension, you may need to explore the finance options to pay for it. One option is to remortgage for home improvements, or to increase your existing mortgage in order to borrow more money up-front. That second option could be a good choice if your current mortgage has competitive rates and you like your provider.

Another option to look into is a second mortgage or secured loan. It’s worth considering, but bear in mind that there are likely to be fees involved with changing your mortgage, and you should pay close attention to the long-term repayment plans.

If you would prefer not to go down the route of mortgages, a specialist home improvement loan may be a better fit for your needs. Low-rate personal loans like this can often be a smart way to fund a house extension.

The stages of a house extension project

Generally speaking, you can break down the construction of a new extension into the following steps:

  • Foundations and groundwork
  • Low-level work
  • Erecting internal and external walls and roofing
  • Putting in windows and doors
  • Guttering, wiring and plumbing
  • Knock-through and plastering
  • Installing light fittings, switches and wall sockets
  • Adding taps and connections

It is good practice the learn the granular detail of every stage of the extension so that you know what questions to ask long before the work begins. This could help to avoid some of the delays that happen so often but are not always planned for in a house extension project.

With good planning, it won’t be long before you get to the fun part – painting and decorating your new addition and breathing new life into your home.