Property expert names seven 'warning signs' to look out for at house viewings that could cost you up to £14k

Searching for a new property is an exciting prospect, whether you're buying your first home, moving up the ladder or searching for a place to retire. But amongst all the excitement, it can be easy for house hunters to miss potential warning signs that could result in costly repairs later down the line.

According to Fiona Lee, director of estate agents Winkworth, June is one of the most popular times for buyers to start looking for their next home. Though surveyors tend to pick up on anything that needs flagging in the buying process, Saga’s home insurance expert, Anna Thunstrom, says there are essential things that you should look out for on the first viewing.

Issues like mould, poor insulation and subsidence can cost anywhere from £200 up to £14,000 to fix. To help prospective buyers avoid costly repairs or an increased insurance premium, Anna has highlighted seven potential warning signs to spot at viewings

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Temperature changes between rooms

Poor insulation can increase energy bills by as much as £340 annually. Insulation in cavity walls can cost around £15 per square metre, amounting to £1,275 for a typical wall area of 85m2. The average cost for double glazing windows ranges from £450 to £1,200 depending on the size, design and materials.

Anna says: “Always check the property’s EPC rating as this tells you how energy efficient the home is; the higher the rating the lower the energy bills are likely to be. Poor insulation is one of the most common causes of temperature imbalances, with poorly fitted windows being a problem now sometimes seen in new builds.

“Pay attention to the temperature of each room. This can be harder to tell during the summer months, but if one room is noticeably hotter or colder than others then it could indicate issues with insulation or the heating and ventilation systems. Ask what type of glazing the windows have and about the insulation in the walls and roof.”

Signs of mould and water damage

The cost of mould removal per room can range from £200 to £400, and up to £1,200 for the whole house. Anna says: “Take the opportunity to examine the walls and ceilings to notice any potential damp and mould problems, such as stains, damp patches upon touch or a musty odour. This can indicate water damage to the property which is costly if left untreated.

“Sellers are legally obliged to disclose damp or mould issues. Ask the owner or agent if you have any concerns, or if the property is freshly painted which can sometimes cover such signs.”

Large cracks

Saga’s own claims data reveals a 240 percent increase in subsidence claims from 2020 to 2022 which could be attributed to the increase in extreme weather events such as heatwaves, storms, and flooding. The cost of fixing a subsidence issue such as large cracks can range from £6,000 to £14,000.

Anna says: “Whilst minor cracks under 0.5 millimetres in width are normal, larger cracks extending from windows, doorways or corners could indicate subsidence - when the property’s foundations have begun to sink.”

She continues: “A surveyor will pick up on this kind of issue, and they’d be able to give you an accurate rebuild cost for insurance purposes. However, to spot early signs at a viewing, try opening and closing internal doors to check for sticking (when it’s tricky to pull open and push close) or any gaps in the frames. Place a small ball on the floor and see if it noticeably rolls in any direction, which could indicate sinking.”

Japanese Knotweed in garden

It could cost anywhere between £1,000 to £12,000 to have Japanese Knotweed removed, depending on the garden size and severity of the infestation.

Anna says: “An overgrown, wild garden may seem like a fun project to redesign, but it’s wise to ask about invasive plants like Japanese knotweed, bamboo, buddleia, and ivy that can be hard to control.

“Japanese knotweed is particularly notorious for causing structural damage to buildings, potentially impacting the property’s value. As a result, sellers are obliged to disclose its presence. It grows rapidly in summer and is most prominent from August to September.

"Keep an eye out for its characteristic shield or shovel-shaped leaves, along with clusters of creamy white flowers that bloom during late summer.”

Trickling taps

The cost of a plumber callout for a faulty tap or leaking pipe averages £300 to £400 a day. Anna says: “Simple checks like turning on bathroom and kitchen taps can tell you a lot about the property’s plumbing. If water comes out as a trickle, it could indicate hard water and limescale buildup which blocks water flow."

Anna adds: "Also see how long it takes hot water to reach the tap; a blockage might delay the flow of hot water. Look for limescale deposits around the base of taps or signs of constant dripping. Additionally, inconsistent water pressure, particularly high water pressure, can affect the flow of water in taps and cause a leak, which may indicate plumbing work could be necessary.”

Missing or loose tiles on the roof

The cost of a new roof is typically between £5,000 and £8,000 depending on the type of roof. Anna says: “Make sure you walk around the property to check the exterior. Tell-tale signs of a roof in disrepair are missing or loose tiles or any roof debris on the floor. If something doesn’t look right, it’s worth a closer inspection and asking about its state before you put in an offer.

“If only a few tiles are affected then it could just be an affordable fix, but if a whole new roof is needed then you could be looking at a hefty bill running into the thousands. A surveyor will always detect any issues to determine necessary repairs to ensure that your offer would reflect a fair price.”

Blocked gutters

The average cost of replacing gutters is around £900, £45 per metre. Anna says: “Try to look at the condition of the gutters. Blocked gutters have the potential to cause leaks indoors and erosion to the property’s foundation, resulting in weakened walls and cracks.

"Foundation problems can inflict significant structural damage, and it's worth noting that most, if not all, home insurance policies don’t cover damage due to poor maintenance, such as not keeping the gutters clear and in good order.

She adds: “Look out for sagging gutters that are caused by debris and water weighing them down. If it's raining, observe if water runs down the side of the house, indicating potential blockages. Also ask how new the drains and guttering are as newer systems are less likely to encounter problems.”

Anna’s three additional questions to gauge the maintenance of the property:

1. Have there been any problems with the boiler? When was it last serviced or installed? - A problematic boiler can lead to costly repairs, inconvenience, and discomfort. Knowledge of past problems and maintenance allows you to assess any potential needs. Asking when it was last serviced can also help you to understand its reliability and efficiency. If the boiler was installed within the last ten years it could still be under warranty. Ask whether the warranty can be transferred to the new owner.

2. Is there a history of flooding? – If the property is near water this question can reveal its risk of flooding and subsidence, or other structural issues. The impacts of flooding can be significant, and it affects the cost of insuring the property which is important to consider.

3. Have there been any major renovations recently? - If the owners have carried out any renovations, they would’ve needed relevant planning and building regulation consents. If the proper permission wasn’t obtained for an extension, for example, then you could have to tear it down. Make sure you ask to see evidence, like builder’s receipts or guarantees and check for a warranty period too.