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The five home improvements most likely to blow your budget

Follow our top tips to avoid overspending next time you update your home

Extension being built

Planning home improvements but worried about your budget? We’ve asked Which? members to tell us whether they’ve ever gone over their allocated budget on a project, and on which aspects, to find out how to reduce the risk. 

In May 2018, we asked 1,493 Which? members* who are homeowners about the renovation work they had done on their homes. 22.4% of them had spent more than they planned on their projects. Double-height extensions most commonly broke the bank of the people who had built one, 19.4% had gone over their budget.

The next most likely project to overspend on is creating open-plan spaces, with 19% spending more than planned here. In third place is building a single-storey extension, to create either a living space or kitchen, for which 17.9% went over their budget.

The graphic below shows the top five renovations that end up costing more, with the percentages of people doing those projects that overspent. Keep reading for more details on how much people went over by, and how you can save on your next project.

If you’re looking to start a home renovation soon, visit our home improvements section for in-depth advice on a range of projects, and use Which? Trusted Traders to find recommended traders vetted by our experts.

By how much do people overspend?

We also asked people to tell us how much extra they had spent on top of their initial planned budget. Answers varied – while some had overspent by less than 10%, others had paid more than double their original allocation. For the top five, most people went over by:

  • between 11% and 25% on their double-height extension
  • between 11% and 25% on creating an open-plan space
  • up to 10% on their single-storey extension for a kitchen
  • between 11% and 25% on their single-storey extension for living space
  • up to 10% on their loft conversion
  • between 11% and 25% on their garage conversion.

We’d recommend that you always start any home improvements with at least a 10% extra buffer in the bank, to help soften the blow of costly additions that may arise once work starts. If you don’t end up spending your contingency, you can put it towards higher-quality fixtures and finishes, or start saving for your next project.

Conservatory being built

Five ways to cut the cost of your build

We asked 213 of our Which? Trusted Traders (in May 2018) for their top tips on how people can keep on track with their budget. Here are the most popular suggestions:

  1. Get quotes from a few traders
    Knowing how much a job should cost will help ensure you’re not overcharged – but you’ll only know this if you get a few quotes and opinions. The extra time could end up saving you hundreds, or even thousands, in the long-run.
  2. Make decisions early on, and don’t change you mind during the job
    With a clear idea of what you want early on, you’ll have time to look for the right – and possibly cheapest – products. Changing your mind on the materials, layout or style you’ve chosen once work has started will soon rack up steep extra labour costs as well as the costs of the new items themselves.
  3. Check that everything you need is included in the original quote
    Take time to read the details of your quote – and request a full breakdown if you don’t have one. You’ll have the chance to spot any products or materials that could be substituted for cheaper ones, and to make sure nothing’s missing.
  4. Be readily available to make decisions
    If you’re not on site, make sure that the traders working on your home have your contact details to help things run smoothly and to time.
  5. Get planning permission/approval early and have plans finalised
    For renovations involving planning permission, architectural drawings or building regulations, get these sorted as early as you can, to save time and money. Make sure you only submit plans you are 100% happy with, as each new application could cost anything from around £200.

Our free home improvement checklist runs through these and the other vital steps to ensure your project comes in on time and budget.
Preview image of home improvements PDF

Saving on your kitchen and bathroom renovation

We regularly speak to people about their experiences with buying their kitchen and bathroom, including how to keep costs down.

When we asked 3,443 kitchen owners (in October/November 2017) how they cut down the costs of their fitted kitchen last year, the top three tips were:

  • Re-used large appliances (27%)
  • Negotiated on costs (26%)
  • Used a fitter they found themselves (22%)

These are just some of the things you can do – visit our page on kitchen costs to see the full list, as well as insider tips from our kitchen pricing investigation last year, which revealed some surprising shortcuts to a cheaper kitchen.

Kitchen being installed

The 3,982 bathrooms owners we asked (in February 2018) employed similar tactics to keep down the cost of their bathroom:

  • Using a fitter they found themselves (36%)
  • Sourcing components themselves in store (27%) or online (27%)
  • Getting different components from a range of stores (26%)
  • Negotiating on the cost (26%)

Our page on bathroom suites includes the full list, as well as durability ratings for big-name bathroom brands, including B&Q, Bathstore and Victoria Plumb.

*Survey of 1,493 Which? members in May 2018 who have had renovation work in their home. The projects were: renovating a kitchen (841); renovating a bathroom (811); building a conservatory/orangery (256); single-storey extension (330); creating an open-plan space (153); loft conversion (126); double-height extension (124); adding a garage (122); converting a garage (78); adding a garden room (73).

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