27 September 2021

A quick guide to extending your home

By Renovation Plan

The pandemic has had many unforeseen effects, including what we ask of our homes. Lockdown has made us re-evaluate the spaces we live in – and it’s no surprise that the property market has boomed since the stamp duty holiday. However, with that wound down and property prices remaining high, moving elsewhere isn’t always an option for those wanting to change their homes – so an extension is the answer. Let’s take a look at everything you need to know before you extend your home.

Planning matters

Getting up to speed on planning permission is a crucial first step. Some types of extensions need planning permission and others fall under permitted development rights, where you don’t have to get approval. As a rule, you will most likely need planning permission if:

  • Your extension will cover at least half the area of land surrounding your home
  • You’re planning to increase the overall height of the building
  • You want to extend to the side of a property, across more than half the width of your house
  • You want to use different building materials to the rest of your home
  • You’re extending towards a road, or building a balcony
  • Your home is listed or in an Conservation Area.

In these cases, you will need to submit detailed plans to your local authority for approval. And, if you want to make sure they’ve got the best chance of being approved, try getting your neighbours on side beforehand so they don’t raise any objections. This is especially true if you live in a semi-detached or terraced house, as your extension will have a bearing on somebody’s else’s house.

Permitted development rights

Under these rules, you can make certain changes without planning permission. They include:

  • Single storey extensions – rear walls can be extended by no more than 8m for a detached, or 6m for a semi or terraced house, and they must be no higher than 4m in height to the ridge and the eaves, with ridge heights no higher than the existing property
  • Double storey extensions – rear walls can be extended by no more than 3m and they mustn’t be closer than 7m to the rear boundary
  • Building materials must be similar to the existing property.

However, the overall size of the extension, its location with regard to your home and the type of windows you want can all affect whether you can extend under permitted development rights. So your best bet is to do your research and confirm your plans with your local authority. Don’t forget, in every scenario your extension will need to comply with building regulations.

Practical designs

Now you have an idea of what you can and cannot do, with and without permission, it’s time to decide on the kind of extension you would like. Consider the aesthetics – do you want an extension that blends in or purposefully stands out from your existing building? Are you after a single storey or a double storey extension? What style of windows are you after?

Once you have some initial ideas, it’s worthwhile to consult an architect or designer who can draw up your ideas professionally and advise you on your options. For example, desirable items like bi-fold doors can be expensive, so it makes sense to ensure your vision aligns with your budget. A good designer or architect will be able to help you find cost-effective alternatives if needs be – just remember an architect will also charge about 15% in fees, so you should budget for that too.

Looking for a local firm with a track record of similar projects is a good starting point, as they will be familiar with the building styles of your area and on hand for support throughout the project. You may also need a structural engineer to provide technical drawings and calculations so you can get your building regulation approval sorted.

Budgetary considerations

How much you want to invest in your extension and how you will fund the work are factors you will need to consider. Start by listing out everything you would like included and shop around for a range of quotes, remembering to check that VAT is included.

If your budget is on the tighter side, then sticking to simpler shapes and features, such as a square extension with standard windows, will keep the costs down – as will doing some of the work yourself to save money on contractors. And don’t forget two-storey extensions are not dramatically different in price to single storey extensions as a lot of the expense is in the foundations.

When finalising your budget, make sure you set aside some money to deal with any unexpected costs which might arise during the building work and don’t forget to factor in your insurance costs too. You will need to let your home insurer know about your plans but it’s highly likely you will need specialist extension insurance during the course of the works.

Building begins

One of the final pieces of the jigsaw is choosing your contractor. For this you’ll need to look into reviews, recommendations and small print. Firstly, check online reviews and don’t be afraid to get in touch with previous customers to go and see their previous work in person.

When you’re satisfied with the quality of their work, run through your contract with a fine-tooth comb – making sure they’ve quoted for exactly what you have specified and interrogating any items not included or any changes of specification before you sign. It’s a good idea to compare at least three written quotations to check where there might be added value or inconsistencies between suppliers. You will also need to set clear payment terms and sign a contract before you begin – taking care to look out for any warranties and insurances too.

If your quotes are consistent and you’re unsure which contractor to use, remember they will be working in close proximity to you potentially for months, so it’s important to feel comfortable around them. And, finally, give yourself the ultimate peace of mind and make sure you get extension insurance before the work begins.