Converting a bedroom could reduce your market value by 20% (nearly £50,000 off the average house). With the UK property market starting to pick up, many Brits will be sprucing up their homes ahead of potential sales. But property experts are warning that some DIY jobs can actually decrease the value of your home by tens of thousands of pounds. Sofa and carpet specialist, ScS, has partnered with estate agents from across the country to reveal the five DIY projects that can reduce your market value the most.

1) Converting a bedroom - £46,000 off (up to 20% of the property value)

Most buyers search for properties based on the number of bedrooms, so converting or removing one can make your home far less saleable.

Alex Willocks, owner of Burbeck Interiors, says: “The value of a home comes from the number of rooms, so merging two small bedrooms, or swapping a bedroom for a bathroom, can actually decrease its worth. Bedrooms are valuable commodities and private space is a lot more desirable than open space.”

Holly Herbert, Head of Content at webuyanyhouse.co.uk, agrees and says that it could knock up to 20% off the property’s value. With the average UK house costing £232,000, this means you could lose £46,000.

2) Adding certain plants to your garden - £35,000 off (up to 15% of the property value)

Many Brits have spent their time in lockdown fixing up their gardens, but adding the wrong plants to your property can harm its value.

Paul Keighley, Residential Partner at Bramleys Estate Agents, says: “Always take advice about tree planting. While certain species have a small root base, others can stretch further than the height of the tree. These roots can crack drains, break driveways and ultimately affect the foundations of the house and become a costly fix.”

Holly adds that the biggest nuisance is Japanese Knotweed, which can be “catastrophic to homeowners”. Depending on the severity, it can reduce a house’s value by up to 15%.

3) Building an extension without the correct planning permission - £35,000 off (up to 15% of the property value)

The right extension can do wonders for your property, but if you don’t get full approval from your council, you’ll cause nightmares for prospective buyers.

Holly says: “Any extensions built without proper planning permission might have to be torn down, putting you at a huge loss, and decreasing your house value. Any new homeowner would have to apply for the appropriate permission and this extra hassle can be very off-putting. This could affect market value by between 5 and 15%.”

4) Converting a garage - £16,000 off (up to 7% of the property value)

While it can be tempting to transform your garage into an extra room, doing so can be detrimental to your sale.

Paul says: “Converting a garage feels like it should add value as you are increasing the size and use of your property, but in reality you are removing parking and storage space, which we have found is always high on a buyer’s checklist.”

Holly says that garage conversions, particularly those which are poorly executed or unnecessary, can decrease a property’s value by up to 7%.

5) Installing lavish garden features, like swimming pools - £16,000 off (up to 7% of the property value)

Fancy garden features like ponds and swimming pools seem luxurious, but they can be expensive to maintain and might be dangerous for children, which isn’t attractive for buyers.

Holly says: “You will likely narrow down your potential viewers with features like a pool or a hot tub, as most people are unlikely to use them often and they can require a lot of maintenance work. They can really put buyers off and lead to a 7% drop in house value.”

Dale Gillespie, Head of Acquisition at ScS, said: “Many Brits love doing DIY, but it’s so important to consider how projects could affect your property’s value. While some will definitely make your home more attractive to buyers, others can have the reverse effect, so make sure you do your homework before you start. Remember that people like to put their own stamp on their homes, so a new owner may just change what you have done anyway.”

To see more DIY jobs that you really shouldn’t do before selling your home, visit: https://www.scs.co.uk/lifestyle/diy-disasters