Doing it yourself could cost you dear
Spring is here – in name at least – and many people might be thinking about things they need to do around the house. But beware – there are some oversights that can mean your property isn’t covered if something goes wrong and if your insurer refuses to pay, it can be very expensive.
Home insurance expert Matthew Harwood at Confused.com has outlined five DIY jobs that he said could invalidate your insurance and cost you thousands.
Water escape
Matthew said escape of water was the most common home insurance claim in the UK; between 2021 and 2024, there were 24,102 escape of water claims, with an average claim cost of £6,786 and total payouts reaching £163.6 million.
It’s often caused by damaged pipework or worn sealant and if the sealant isn’t reapplied correctly, it can let water seep into walls, floors, and ceilings, leading to leaks and hidden structural damage.
Possible costs you could face if your insurer won’t pay:
- Replacing damaged flooring: £150 to as much as £5,000 if subfloor, joists, or more than one room is affected
- Replastering ceilings and walls: average £300 to £1,200, depending on room size
- Repairing joists or timber structures: £1,500 to £2,000, depending on scale of the problem
Checking appliances for leaks, keeping sealant around baths and showers in good condition and insulating exposed pipes before colder months can all help prevent problems before they start.
Gutters
If your gutters are blocked or have been repaired poorly after damage, it can cause rainwater to overflow. The water running down exterior walls can lead to penetrating damp, damaged insulation and mould growth inside the house.
Most insurers say looking after guttering is the homeowner’s responsibility, so claims linked to poorly maintained gutters can often be rejected – but if damp penetrates deep into the building structure, costs could collectively be as much as £10,000.
Possible costs you could face if your insurer won’t pay:
- Damp proof treatment: £500 to £2,000+
- Replacing damaged insulation: £500 to £1,500
- Replastering damp walls: £300 to £1,200 per room
- Brickwork repairs and repointing: £1,500 to £4,000 for whole house
Simple steps like clearing gutters when bad weather is forecast can help protect homes from costly damage.
Decking
If you have dreams of new decking for a springtime garden refresh, it’s best to consult an expert. When installed incorrectly, decking can trap water against the house or stop it from draining away and it can cause long-term damage.
You can also cause problems by pressure washing existing decking; it can add to water damage, and even damage brickwork and masonry with the force of the water.
Possible costs you could face if your insurer won’t pay:
- Removing unsafe decking: £500 – £2,000
- Fixing damp caused by trapped moisture: £2,000 – £8,000 depending on the scale of the problem
- Severe damp penetration leading to foundation issues: as much as £10,000 – £15,000
- Repairing damaged brickwork after pressure washing problems: £1,500 – £4,000
Electrical
Electrical problems can be some of the most expensive DIY mistakes a homeowner can make. If you don’t know what you’re doing, improper wiring – whether that’s fixing a plug socket or installing lights in the garden – could cause electrical faults and this can lead to overheating and even fires.
Confused.com said its data showed that fire was one of the most expensive home insurance claims, with an average payout of £22,046, so it can cost a lot if your insurer rejects your claim because of faulty DIY wiring.
Possible costs you could face if your insurer won’t pay:
- Replacing electrical system: £2,000 – £6,000
- Replacing damaged belongings and furniture: £5,000+
- Fire and smoke damage repair: could exceed £40,000, depending on the extent of the damage and how many rooms are affected
Roofing
Winter weather can affect your roof, with storms dislodging roof tiles that were already a little loose, so many might think about making repairs themselves when spring arrives. However, these repairs can cause bigger issues if they’re not done correctly.
From causing damage to surrounding tiles when accessing the roof, to damaging the waterproof membrane, or accidentally blocking ventilation, mistakes that seem minor can let water in and cause leaks and damp.
Possible costs you could face if your insurer won’t pay:
- Repairing roof structure: £2,000 – £6,000
- Replacing ceiling plasterboard and insulation: £1,500 – £4,000
- Damp and mould treatment: £1,000 – £3,500
- Repairing water-damaged electrics: £1,000 – £3,000
Matthew said: “Confused.com’s data shows that the average cost of home insurance claims has risen significantly over the past three years. Rising UK inflation, along with more frequent severe weather linked to climate change, has driven the rise in claim payouts.”
Because of these rising claims, insurers are paying closer attention to the claims and claims for damage caused by bad DIY, poor maintenance, or warning signs of issues being ignored are often rejected, he said.
Matthew added: “We know many residents are hesitant to make a claim due to concerns about rising costs, which is why prevention and preparation are so important. It’s also vital to make sure you’re covered for the right amount, so you’re not left out of pocket if you do need to claim.
“Our contents insurance calculator can quickly estimate how much cover you need based on your belongings, so you can make sure you’re properly protected and not overpaying. And if you ever do need to claim, our guide on how to make a home insurance claim explains each step, helping you feel confident about what to do next.
