Is Your Home Worth Less Than You Think? 12 Hidden Value-Killers Explained

When it comes to protecting your home's value, most people think of the obvious culprits — structural issues, damp, or that dreaded Japanese knotweed. But did you know that something as seemingly routine as an old swimming pool could strip nearly a fifth off your property's market value?

At Mortgage Tree, we know that your home is likely your most significant financial asset. Whether you're planning to sell, remortgage, or simply want to protect your equity, understanding what can knock value off your property is essential — especially when it comes to securing the best possible mortgage deal.

New research has revealed 12 surprising factors that can significantly reduce your property's appeal and your potential profit. Based on the current average UK house price of £268,319, here's what you need to know.

💡 Mortgage Tree Tip: Lenders assess your property's condition and value before approving a mortgage. Issues like subsidence, flood risk, or Japanese knotweed can affect not just your sale price, but your ability to secure a mortgage at all. Speak to one of our advisers before listing — we can help you plan ahead.

The 12 Biggest Value-Killers

1. Subsidence   −20% (−£53,664)

One of the most serious structural issues a property can face. Subsidence indicates a shift in your home's foundations and can be both expensive and time-consuming to fix. Lenders are extremely cautious about properties with a history of subsidence, and many will require specialist surveys before agreeing to lend. If you suspect subsidence, get a structural engineer involved early — and talk to your Mortgage Tree adviser before putting your home on the market.

2. Old or Disused Swimming Pool   −19.6% (−£52,591)

Pools may once have been a luxury selling point, but an outdated, damaged, or unused pool is seen by buyers as a financial liability. Removal or renovation costs can be substantial, and from a mortgage perspective, non-standard property features can complicate valuations. If you have a pool you're not using, it may be worth getting a quote for removal before you list.

3. Japanese Knotweed   −15% (−£40,248)

Infamous in the property world, this invasive plant can cause serious structural damage and is notoriously difficult — and costly — to eradicate. Many mortgage lenders will refuse to lend on properties affected by knotweed, or will only proceed with specialist indemnity insurance and an approved treatment plan in place. This is one issue where early professional intervention can make the difference between a sale and a collapsed chain.

4. Nearby Pylons, Towers or Turbines   −14% (−£37,565)

Powerlines, phone towers, and wind turbines can spoil views and raise concerns among buyers about potential health implications. Some lenders also consider proximity to certain structures when assessing risk, which can affect the mortgage products available to buyers of your property.

5. Flood Risk   −13.6% (−£36,491)

Living in a high-risk flood zone typically means higher insurance premiums — and can be a dealbreaker for cautious buyers and their lenders. Many mainstream mortgage providers either won't lend on high-risk flood properties or will require specific buildings insurance as a condition of the offer. Mortgage Tree works with a wide panel of lenders, including specialists who can help buyers in flood-risk areas find appropriate financing.

6. Unkempt Neighbouring Homes   −11% (−£29,515)

Even a pristine property can be dragged down by poorly maintained homes nearby. While you can't control your neighbours, buyers will factor in the overall feel of the street when making their offer. It's worth being realistic about how your immediate surroundings are likely to be perceived.

7. Problem Neighbours   −10% (−£26,832)

Noise complaints, disputes, or antisocial behaviour can make a sale significantly harder. Sellers are legally required to disclose known neighbour disputes on the TA6 property information form — something that can put buyers off or prompt renegotiation. Being upfront and honest is always the best approach.

8. Messy Garden or Exterior   −8.2% (−£22,002)

First impressions count for a great deal. Overgrown lawns, peeling paintwork, and cluttered outdoor spaces can put buyers off before they've even crossed the threshold. Fortunately, this is one of the most affordable problems to fix — a weekend's tidying and a tin of exterior paint can deliver a meaningful return.

9. Limited or No Parking   −6.8% (−£18,246)

Off-street parking remains a top priority for the majority of UK buyers, particularly families and those in suburban or semi-rural areas. If your home has no dedicated parking, be realistic about pricing and consider whether there are any options — such as converting a front garden — that could add appeal before you sell.

10. An 'Unlucky' House Number   −6% (−£16,099)

It may sound surprising, but some buyers actively avoid properties numbered 13, particularly in more traditional communities. While you can't change your house number, being aware of any buyer superstitions in your area can help you set realistic expectations.

11. Flight Path   −5.5% (−£14,758)

Properties under major airport flight paths can suffer from persistent noise pollution — a significant deterrent for families and buyers seeking a peaceful home environment. If you're near a major airport, it's worth checking whether your home qualifies for any noise insulation grants, which can help mitigate the impact.

12. Nearby Power Stations   −5% (−£13,416)

Whether it's visual disruption, environmental concerns, or perceived health risks, proximity to a power station is a red flag for many buyers. Lenders will sometimes apply additional scrutiny to valuations in such areas too.

What Can You Do?

While several of these factors are outside your control, many aren't. Here's a practical starting point:

✔  Tidy the garden and repaint the exterior — low cost, high impact.

✔  Address structural issues early — getting a survey before marketing can prevent nasty surprises down the line.

✔  Treat Japanese knotweed with a certified specialist and get a management plan in place — this is often a lender requirement.

✔  Consult a mortgage adviser before listing — knowing what lenders will and won't accept could save your sale.

Presentation is everything. Buyers fall in love with homes that feel light, well-maintained, and cared-for. Make sure yours ticks every box within your control.

🏡  How Much Is Your Home Worth — and What Mortgage Could It Unlock?  If you're thinking of selling, remortgaging, or simply want to understand your financial position, Mortgage Tree is here to help. Our expert advisers work with a wide panel of lenders to find the right solution for your circumstances — including properties with complex features or non-standard situations.  Get in touch with Mortgage Tree today for a free, no-obligation conversation.

*Based on UK average house price of £268,319. Percentage deductions sourced from Yopa research. Mortgage Tree is a trading name authorised and regulated by the Financial Conduct Authority. Your home may be repossessed if you do not keep up repayments on your mortgage.