Millions of Brits could be in for a shock if they need to claim on their homes insurance – as companies are refusing to pay out for damage caused – both directly and indirectly – by DIY jobs done in the home.

Now MyBuilder.com, the reliable way to hire tradespeople, is advising people of the jobs they must never tackle themselves, or face being out of pocket should a claim be raised.

Not only does this loophole appear for botched DIY jobs, but it can also be relevant for standard maintenance jobs around the home that have been neglected, or badly done. While some of these tasks are actually illegal to do yourself, others are perfectly legal but will leave you uninsured should any related problems arise.

One example from MyBuilder.com is servicing your boiler. Doing this yourself is actually illegal – but should you decide to save the cost and skip your service, this could also lead to expensive problems. Should your boiler break and cause damage to your home that requires an insurance claim, lack of an annual service can be enough for your insurance company to refuse a payout.

Badly done DIY – or lack of general maintenance of homes – are reported to cost millions of pounds every year in denied insurance payouts. Many home insurance companies have it written into the small print that any claims relating to damage caused by improperly maintained properties will not result in a payout. This includes failing to carry out general maintenance (such as clearing out your gutters) but also includes any damage directly – or indirectly – caused by DIY jobs.

Andy Simms, a home maintenance expert from MyBuilder.com, said that policyholders should check carefully to see if they are taking a risk by using DIY or even neglecting regular jobs around the home.

“It’s easy to fall behind on home jobs, or think you can manage it yourself. But the reality is that many household jobs require a professional, and in choosing to ignore that you could cost yourself a small fortune.

“And many “easy” DIY jobs are anything but – particularly with fixes or maintenance on boilers, heating systems, or electrics. These should always be carried out by certified experts, or you will face a big bill should it all go wrong.”

MyBuilder has put together a list of issues that may lead to your home insurance policy becoming invalid, and provided some tips to make sure you don’t fall into the insurance trap.

Blocked gutters

It may sound like no big deal – but actually blocked gutters can lead to significant damage to your property. They are a common cause of damp in your home, as water overflow trickles down the exterior of your building, causing leaks which can quickly become an expensive problem. If your insurer has reason to believe that your gutters have not been cleared, they are unlikely to pay out for any related damp issues in your home.

Installing your own solar panels

Solar panels are becoming very popular – but they are also expensive. Some people are turning to buying and installing their own, which is not only potentially dangerous, but is likely to render your insurance useless in the event of a problem. There is no harm in shopping around for second hand or discounted panels, but always get an expert to install them.

Installing animal flap

Cat and dog flaps might make your life easier in some ways, but if you install them yourself you could compromise the safety of your home. Most insurance policies will ask to know if an animal flap is a feature in your home, and if you install one without telling them, your insurance could be void.

Not mending damage promptly

Roof tiles coming off, cracks in walls or broken windows are all good examples of damage that needs to be repaired – and quickly. Should an issue occur in your home that can be attributed to problems that should have been fixed, you could face no payout.

Not having secure windows and doors

Insecure windows and doors are a big problem when it comes to payouts after burglaries. Any cracks in windows, weaknesses in frames or dodgy locks should be replaced with urgency. In the unfortunate event of a break in, if an insurance provider suspects a weakness in security, you will struggle to get a payout.

Servicing your own boiler

If you’re not a gas professional or a Gas Safe Engineer, then servicing your own boiler is illegal under the Gas Safety (Installation and Use) Regulations 1998.  Doing a DIY job on any of these systems is not only illegal but a very bad idea – and is not only risking your payout, but your life. Worryingly, in a recent survey from MyBuilder.com of people affected by the cost of living crisis, 23% of respondents had not serviced their boiler in the past 12 months.