Expert lists five common DIY mistakes that can cost homeowners up to £50,000 to fix

Millions of homeowners will pick up their tools this summer to work on DIY projects to transform their houses on a budget. But while putting up a wonky shelf can be easily fixed, some will try their hand at much bigger projects.

Tackling your own home improvements without the necessary research, tools, or knowledge can quickly unravel into a nightmare, where the costs of a mistake can rack up to thousands of pounds.

Beth Boulton, marketing director at leading home improvement specialists Eurocell, lists some of the most common DIY mishaps that can leave Brits up to £50,000 out of pocket.

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Knocking through walls

"Open-plan living is a style many homeowners have fallen in love with," says Beth. "Open spaces with plenty of natural light have been proven to be beneficial to our mental and physical health, and it’s no surprise many of us are ogling our walls with thoughts of knocking them through to create a bigger room.

"Usually, knocking through a wall to create a wide open space costs around £2,500, or less if you’re adding in a smaller doorway. But it’s important to remember that not every wall can be knocked through, at least not without the proper structural considerations and support. Removing a load-bearing wall can result in dangerous ceiling collapses and make a home completely unlivable."

Repairing this damage can be extremely costly, with renovations running up a bill of £10,000 or more.

DIY extension

Beth says: "Extensions are ever-popular up and down the country. The allure of adding new rooms and driving up your house value is strong, and today’s trends include open-plan kitchen and dining rooms that aren’t often found in older properties, leading many to turn to extending their homes as a potential solution.

"Building your own extension might seem like a good way to save on builders’ fees, but in reality, you’d need to have an in-depth knowledge of construction, building regulations, electrical and plumbing systems in order to create a safe new space in your home - something that normally requires several different tradespeople with various specialisms."

Failure to create a safe, insulated space with sound structural integrity can be incredibly expensive. Homeowners face the prospect of tearing down their extension and drafting in the experts to rebuild it properly. Depending on the size of your extension, this could cost between £20,000 and £50,000 and make your home completely uninhabitable until work is completed.

Tackling your own groundwork

"DIY enthusiasts often underestimate the work necessary to complete proper groundwork, which can lead to expensive repairs down the road," says Beth.

"Laying foundations and ensuring proper drainage is incredibly important for ensuring the structural integrity and longevity of extension work or garden improvements.

"Failing to ensure proper levelling and drainage can cause foundations to fill with water and crack, costing thousands of pounds to fix. In the worst cases, it can cause your foundation to subside, which can cost over £20,000 to fix, as well as months of surveys and visits from structural engineers."

Ignoring planning rules

Beth says: "Turning a blind eye to planning regulations can put you in some very hot water. Not all projects require planning permission, but it’s always wise to check before you start your project, not after.

"If you go ahead without planning permission, and it turns out later that you did need it, you can apply for retrospective approval. The planning officer could require you to alter your plans, even if you’ve already completed construction. If retrospective planning permission is refused, you’ll be faced with knocking down the entire project.

"Obviously, this can be expensive. However, failure to comply with an enforcement notice is a criminal offence and you can face prosecution in the most extreme cases."

The expert adds: "Here, you can face prosecution in a Magistrates’ or Crown Court. The maximum fine in a magistrates court is £20,000, but there is no limit on the maximum fine a Crown Court could impose."

Removing health risks

"Homes built before the 1980s were sometimes built with hazardous materials - even though they were thought to be safe at the time," says Beth.

"The most notorious of these is asbestos, which when disturbed releases tiny fibres into the air. Inhaling these fibres can cause several severe health conditions, such as asbestosis, mesothelioma and lung cancer.

"If you need to remove asbestos, this always has to be done by a professional. Failure to do so leaves you at risk of developing the serious health conditions listed above."

She says that the first step is to bring in an asbestos surveyor, who can identify where asbestos is located in your home and also how much there is. Then, it’s a case of bringing in an asbestos removal expert to safely remove it from the home. This can cost anywhere between £1,500 and £5,000.