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Extensions & Structural Alterations: The Property Improvements to Add Most Value

It’s common knowledge that home improvements can perk up an otherwise mundane property and add more value when it comes time to sell.

But before you start planning a new kitchen, extension, or conservatory it is a good idea to consider the costs of each possible improvement and see if the value they actually add will make the time and effort you need to put in worth while.

We'll also look at the need for ensuring you have structural insurance in place for any alterations you make.

Most valuable property alterations

Last year the National Association of Estate Agents conducted a survey about home improvements that add the best value to a property. Half of the estate agents who responded said that adding a bedroom was the biggest value booster, while a third recommended kitchen improvements. Others suggested adding a conservatory or converting a garage.

Research based on actual sales show that the most valuable improvements are a new bedroom (extension), loft conversion, extra bathroom, new kitchen, or installing a new central heating system.

So how much do these leading improvements cost, and how much value do they actually add?


Conservatories add rooms to a home, but building one means giving up some garden space. If you plan to implement one that’s under a certain size, you can do it under permitted development and won’t need planning permission.

Conservatories are great ways of adding extra home space for less. They can bring in a more light and open feel to adjoining rooms and even support an open plan design although you may have to consider building regulations on closing of areas with doors for fire safety.

Building a conservatory can add around 5 percent to your home’s value, but will cost between £4,000 and £10,000.


Extensions vary in size scope, from adding a new bedroom to building two entirely new storeys. Wide variations make it difficult to determine how much they cost in general or how much value they add as a category.

Specialists in Construction Insurance

A well-built extension that adds more rooms and enhances the character of your home can be a major selling point, and you can enjoy it for many years prior to placing the home on the market.

New Kitchen

Kitchens are a home’s focal point and are often the first thing a homebuyer wants to improve, so if you present them with a modern and attractive space, they may be willing to pay more.

Open plan kitchens that blend into dining and living spaces are the current trend. According to research by consumer advisory magazine Which? a new kitchen costs an average of £8,000 but the improvement could add around 6 percent to your home’s value.

Loft Conversions

Adding an extra bedroom can raise the value of your home by 9 to 10 percent, especially if it’s a loft conversion. Don’t consume living space to accomplish the conversion as any increase in value will be limited, if possible expand into your loft or convert an unused integral garage, and the returns will be worth it.

Depending on your property’s size and location, a small loft conversion costs around £15,000 and a large one anywhere between £25,000 to £40,000.

Your home insurer will need to be informed of any changes and you should seriously consider taking out structural warranty to cover the building work, especially if any modifications to the roof structure support, timbers, RSJs etc. are involved.

Extra Bathroom

Thanks to a growing demand for en-suites, an extra bathroom can be a strong selling point. Adding a bathroom tacks up to 6 percent onto your property’s value. Depending on the fixtures, fittings, and tiles used, you could pay anywhere between £2,500 to more than £6,000 for the improvements for a professional to do the work, but of course if you go the self build route you can save a significant percentage of the costs mentioned here.

Structural Insurance

To fund these improvements, you’ll need to save up a lot, take out a personal loan, or borrow extra on your mortgage.

How ever you pay for the building work, you will be placing a reasonable amount of money into the investment in your home. It is important to protect that investment should something go wrong with the design, construction, building materials or workmanship of the alterations.

Without this insurance in place you could be forced to pay out even more money to put things right should a structural fault occur, and your home could even become unsafe to inhabit in the worst case scenario.

As a leading provider of building defects insurance for new developments, self builders, and homeowners carrying out extensions and renovations to their property, CRL can help to provide peace of mind.

For more information on how we could help on your home improvement project, get in touch with our team today.


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