What Devalues a House?

If you’re planning to sell, it’s natural to wonder what devalues a house and whether anything could affect the price buyers are willing to pay.

Some factors, like structural problems or Japanese knotweed, can have a significant impact. Others, such as outdated décor or a poor EPC rating, may not reduce your home’s value directly but could make it harder to attract buyers or achieve your asking price.

The good news is that not every issue is a deal-breaker. Many can be improved before your property goes on the market, while others simply need to be priced appropriately and explained honestly.

In this guide, we’ll look at the most common things that devalue a house, what they mean for sellers, and which issues are worth tackling before you move.

Structural Problems and Subsidence

Structural issues are one of the biggest concerns for buyers because they can be expensive to investigate and repair.

Cracks, movement and foundation issues

Not every crack means there’s a serious problem. Hairline cracks caused by normal settling are common, particularly in older homes.

However, larger cracks, sticking doors or windows, sloping floors or signs of movement could indicate structural issues or subsidence. If buyers spot these during a viewing, they’ll often want a survey before proceeding.

If you’re unsure, it’s worth getting professional advice before marketing your property.

How much can structural problems devalue a house?

The impact depends entirely on the severity of the issue.

Minor movement that’s already been repaired and documented may have little effect, while unresolved subsidence can reduce buyer demand and make mortgage lenders more cautious.

Providing evidence of previous repairs and structural reports can help reassure buyers and prevent unnecessary delays.

Japanese Knotweed and Invasive Plants

Japanese knotweed has become one of the best-known issues that can affect a property’s value.

Why lenders and buyers treat knotweed so seriously

Japanese knotweed can spread quickly and damage walls, drains and hard surfaces if left untreated.

Although attitudes have softened in recent years, many mortgage lenders still want evidence that the plant is being professionally managed before they’ll approve lending.

For buyers, the concern is often the cost of treatment rather than the plant itself.

What to do if your property has Japanese knotweed

If knotweed is present, don’t ignore it.

A specialist treatment plan with an insurance-backed guarantee can provide reassurance for buyers and lenders alike. Being open about the issue is usually far better than hoping it won’t be discovered later.

Damp, Mould and Water Damage

Damp is one of the first things buyers notice during a viewing, and one of the biggest reasons they begin questioning how well a property has been maintained.

How to spot damp before it affects your sale

Look out for:

• Damp patches on walls or ceilings

• Peeling wallpaper or bubbling paint

• Musty smells

• Black mould around windows or behind furniture

• Water stains after heavy rain

Some causes are relatively minor, such as poor ventilation, while others may point to roof leaks or rising damp.

Addressing the cause before listing your home can help avoid concerns during viewings.

The impact of damp on property value

Visible damp doesn’t automatically reduce your property’s value, but it can reduce buyer confidence.

Many buyers assume the worst when they see signs of water damage, even if the underlying issue is straightforward to fix.

Taking care of repairs before marketing your home can make it easier for buyers to focus on the property’s strengths rather than potential problems.

If you’re unsure how buyers might view your property, understanding how estate agents value your home can give you a better idea of which issues are likely to affect its market value.

A Poor EPC Rating

Energy efficiency has become much more important to buyers over the last few years, particularly as energy bills remain a major household expense.

Why energy efficiency has become a deal-breaker for buyers

A low EPC rating doesn’t automatically devalue a property, but it can make buyers think twice.

Homes with better energy efficiency are often cheaper to run, which can make them more attractive, especially to first-time buyers watching their monthly budgets.

Some mortgage lenders also offer green mortgage products for more energy-efficient homes.

How to improve your EPC rating before selling

Simple improvements can make a difference, including:

• Upgrading loft insulation

• Installing LED lighting

• Servicing or replacing an older boiler

• Draught-proofing doors and windows

You don’t always need major renovations to improve your home’s energy efficiency.

No Off-Street Parking

Parking is one of those features buyers often don’t think about until they need it.

How much does a lack of parking devalue a house?

The answer depends entirely on location.

In rural areas or suburbs where most homes have driveways, a lack of parking can make your property less appealing. In city centres, however, buyers may expect on-street parking or rely on public transport instead.

If your property comes with allocated parking, permits or nearby parking facilities, make sure these are highlighted in your listing.

Noise Pollution and Busy Roads

The property itself might tick every box, but the surrounding environment matters too.

Flight paths, train lines and main roads

Heavy traffic, railway lines, busy junctions or regular aircraft noise can affect how buyers feel during a viewing.

While these factors don’t always reduce property values significantly, they can narrow the pool of interested buyers.

Visiting your own property at different times of day before listing can help you understand what buyers are likely to experience.

Can you do anything to offset noise issues?

You can’t move your house, but you can improve how it’s presented.

Double glazing, well-maintained gardens and careful staging during viewings can all help minimise the impact of outside noise.

If the location offers strong transport links or local amenities, these can also help balance buyers’ perceptions.

Neighbourhood Factors and Local Area Decline

Your property’s value isn’t determined by the house alone.

Crime rates and antisocial behaviour

Buyers often research local crime statistics, school catchments and neighbourhood reviews before making an offer.

If an area develops a poor reputation, it can affect demand, regardless of how well presented the property is.

Proximity to pylons, phone masts and industrial sites

Features such as electricity pylons, mobile phone masts or nearby industrial buildings can sometimes put buyers off, even where there’s no proven health risk.

Similarly, unpleasant views, heavy traffic or nearby commercial premises may affect buyer interest.

These aren’t always deal-breakers, but they’re factors buyers commonly consider when comparing properties.

Neighbour Disputes and Boundary Issues

Boundary disagreements can become a much bigger issue than many sellers realise.

Why unresolved disputes can kill a sale entirely

If you’ve had a formal dispute with a neighbour, you’ll usually need to disclose it during the conveyancing process.

While minor disagreements won’t necessarily stop a sale, ongoing legal disputes or unresolved boundary issues can make buyers nervous and slow down the transaction.

If possible, resolving issues before putting your property on the market is often the best approach.

Outdated Décor and Overly Personalised Interiors

First impressions matter, but buyers usually look past cosmetic details if they can see the property’s potential.

The difference between dated and devaluing

An avocado bathroom suite or floral wallpaper won’t necessarily reduce your home’s value on paper.

However, very dated interiors or highly personalised décor can make it harder for buyers to picture themselves living there. That can lead to fewer viewings, lower offers or a longer time on the market.

Quick fixes that make a difference before you sell

You don’t need to renovate your entire home before selling.

Simple improvements like repainting walls in neutral colours, replacing worn carpets, improving lighting and decluttering can help buyers focus on the space itself rather than your personal style.

If you’re preparing to sell, our guide on how to sell your house quickly includes more practical tips to help your property stand out.

Problematic Extensions and Unpermitted Building Work

Extra space can add value, but only if it’s been completed properly.

Conversions done without planning permission

Loft conversions, extensions and garage conversions should comply with planning rules and building regulations where required.

If the correct approvals weren’t obtained, buyers and mortgage lenders may have concerns.

Even if permission wasn’t needed, it’s important to have the relevant certificates and paperwork available.

What happens if you can’t produce the paperwork?

Missing documentation doesn’t always stop a sale, but it can delay the conveyancing process while buyers investigate further.

In some cases, sellers may need to obtain retrospective approvals or indemnity insurance before completion.

A Swimming Pool or High Maintenance Garden Features

Not every expensive home improvement adds value.

Why pools often cost more than they add

While a swimming pool may appeal to some buyers, many see it as an ongoing expense that requires maintenance, heating and insurance.

Large ponds, extensive water features and high maintenance landscaping can have a similar effect.

Instead of adding value, these features can reduce the number of potential buyers interested in your property.

Smoking Indoors

Smoking inside a property can leave lasting effects that aren’t always obvious to the homeowner.

How cigarette smell affects buyer perception and offers

Lingering smoke odours, yellowing walls and nicotine staining can make buyers question how well the property has been looked after.

Even after deep cleaning, smells can remain in carpets, curtains and soft furnishings.

Professional cleaning and redecorating before marketing the property can help create a fresher first impression.

How Much Can These Factors Devalue Your Home?

There’s no single answer to what devalues a house the most, as every property is different.

Some issues, such as structural movement or Japanese knotweed, can have a significant impact because they affect mortgage lending and buyer confidence.

Others, like dated décor or a lack of parking, may simply reduce demand or make buyers negotiate harder.

Here’s a general guide:

These are broad indications only. The actual impact depends on your local market, the condition of your property and current buyer demand.

What Can You Do Before You Sell?

Not every issue needs fixing before you put your home on the market.

Issues worth fixing vs issues worth disclosing

Focus on repairs that improve buyer confidence, such as fixing leaks, treating damp, tidying the garden and addressing obvious maintenance issues.

For larger issues that can’t easily be resolved, honesty is usually the best approach. Providing surveys, guarantees or repair documentation can reassure buyers and help avoid delays later.

Get a free valuation to understand where you stand

If you’re unsure which issues are likely to affect your property’s value, getting an expert opinion is a good place to start.

A local property expert can explain how your home’s condition compares with similar properties nearby and help you price it realistically.

You can also browse our guides for sellers for more advice on preparing your home for the market.

Ready to sell?

Many of the things that devalue a house can be improved with a little preparation, while others simply need to be reflected in the asking price. Understanding your property’s strengths and weaknesses before you market it can help you attract the right buyers and avoid unnecessary surprises later in the process.

If you’re thinking about selling, book a house valuation with Purplebricks to find out what your home could be worth and get expert advice on the best way to maximise its value before it goes on the market.