Cracks in the walls

If you’re seeing cracks in the walls then your house could likely be showing the first and most obvious signs of being structurally unsound. If your walls are cracking, something just isn’t right, whether the structure is uneven or, most likely, the building has issues in its foundation. Regardless, get those cracks checked before things go downhill.
Stains under the windows

Another way of telling your house has some major structural issues is if there is discolouration under your windows, either on the inside or outside. This shows that the building has serious water damage. Water has probably gotten in around the windows and is weakening the entire structure around the frame. If this is the case, your house could be close to falling apart.
Slanted floors

Maybe your walls are straight and sound as can be, but perhaps you can’t say the same about the floors. If you feel like your floors could be used as a slide, no matter how steep, you should be concerned. The construction of the house must have had some flaws, because it probably means that the ground beneath the foundation was not sufficiently compacted before building began.
Peeling paint in the bathroom

Old homes will have peeling paint, that’s just the way of things. You should be concerned if the bathroom paint is peeling, though. It’s your house letting you know that the bathroom has some water damage going on. In fact, it’s probably not new. This means the roof might actually have leaks which can also lead to mould and rotting planks in the roof.
The baseboards are falling off

When a baseboard falls off, the instinct can be to ignore it and just prop it back up as if nothing happened, but that’s definitely not what you should be doing. There is a reason the baseboards have come unattached from the walls, and those reasons are generally to do with foundational issues that occurred when the house was first built.
The ground around the house is shifting

Sometimes the earth around your house is the best indicator that there is something wrong with the structure of the house itself. You might have water leakage going on in your house which is causing the earth around it to sink and become mushy. If the land around your house is eroding, then you likely need to get on those repairs as soon as possible.
Doors and windows are hard to close

The doors and windows in the building were almost definitely perfectly aligned when the house was first built. If they are now difficult to shut and open properly, then it could be a sign of subsidence which means the ground under the property is moving. This subsidence could have but the door and window frames askew, making their use more difficult.
Your walls are warped

If the walls are warped and just not quite flat, then they could be absorbing water. The water in the walls bulges out, creating a distorted shape. This kind of water damage can make your walls begin to crumble. If this is happening in your home, you’ll probably notice it around the baseboards first, so pay attention to them.
The floor is bouncy

A good bounce is great fun on a trampoline or diving board, but it’s not a feature you want in your home flooring. If your floors are feeling spongy and standing on them pushes them down noticeably, you are dealing with structural issues. This could be a case of a termite infestation which would explain the weakened, spongy wood perfectly.
Your home smells damp

You might think that a damp smell just means your house isn’t clean enough, but it usually goes much deeper than that. A damp smell signifies mould somewhere in your house. If there is mould, the building has some sort of structural issue that is allowing water damage. Check for leaks around your sinks, and see if your toilet is rocking – if it is, that could be causing the smell.
You see termites

Your pipes are discoloured

The lights are flickering

Whilst they might improve the vibes at your next house party, flickering lights are rarely a good sign. One light playing up is probably just a dodgy bulb, but if multiple lights are flickering then it’s likely to be a problem with your house’s wiring, which could point towards a more serious problem such as sinking foundations.
Sagging areas on your roof

Problems with your roof can quickly cause other issues – such as mould and water damage – and should be dealt with in a timely manner. One of the key indicators that your roof is in need of repairs is sagging spots. These can be caused by a variety of factors, but none of them are good.
Sudden jumps in your water bills

Sudden, unexpected spikes in your water bill are a sign that there’s a problem with home’s plumbing. A running toilet is often the culprit, so that should be your first point of investigation. If all of your toilets are in good working order, you might have a serious leak somewhere in your plumbing system, which needs to be located and dealt with as a matter of urgency.
Discolouration around electrical sockets

Research by the National Fire Protection Agency has found that every year around 50,000 house fires in the US are caused by problems with electrical sockets. Discolouration around sockets – especially if it’s black – could be an indication that the socket is overloading and getting dangerously hot, which could eventually lead to it catching fire. If you spot this alarming sign, immediately switch off the socket and call an electrician.
Warped roof tiles

You can tell a lot about a home’s health by the state of its roof. Warped shingles, for example, indicate that the house isn’t getting enough ventilation, causing moist, warm air to get trapped in the attic. Over time, this can lead to mildew problems and that can cause serious damage to your home. Certain strains of mould also come with a number of health risks, and extended exposure can lead to permanent respiratory issues.
Foul smells coming from the drains

Rusty water coming from your taps

Discoloured water coming out of your taps should be an immediate cause for worry, as it often indicates a major issue with your home’s plumbing. You’re most likely to see rusty water coming out of your taps when you use hot water, as the root of the problem normally lies with your home’s water heater. If the corrosion hasn’t progressed particularly far, repairs may be possible, but most of the time the solution is going to be an entirely new heater.
You keep finding moisture around your AC unit

If you live in one of the hotter parts of the world, you probably have your AC unit running a good amount of the time. These units are prone to a number of faults, the most serious of which is a refrigerant fluid leak. Many AC units use freon as a coolant, which works well but is dangerously toxic to humans. If you find moisture around your AC unit and you can’t figure out where it came from, switch it off immediately and call a specialist repair company.
Food in your fridge keeps going off

If you keep finding yourself throwing out refrigerated food that’s well within its use by date, the culprit might be a fridge that’s on the way out. Whilst it’s generally pretty obvious if your fridge packs up entirely, problems with the compressor can cause unpredictable fluctuations in temperature that you might not be aware of. Fortunately, a compressor can normally be replaced, which is a far cheaper option than replacing the whole fridge.
Your breaker box smells of smoke

Low water pressure

You spot tiny holes in wood around your house

Your breaker box is tripping more than usual

Cracks appearing in your windows

Your washing machine hose is bulging

Washing machine hoses are made of rubber, and over time the high pressures they are subjected to can cause them to degrade. As the rubber softens it can begin to bulge, which is a clear sign that the hose it on its way out. Failure to replace the hose at this point will likely result in severe flooding, so it’s best to take action pre-emptively.
You keep finding clumps of chewed paper

One of the telltale signs of a rodent infestation is little clumps of shredded paper turning up all around your house. If you suspect that a family of mice or rats have moved in, seek assistance as soon as possible. Rodents reproduce incredibly quickly, and within a few months you might find yourself contending with hundreds of the creatures.
You notice white residue on a brick chimney

If you’re lucky enough to own a home with a fireplace, you should periodically check your chimney for a thick white residue. This is caused by moisture pulling minerals out of the bricks, and it can be a sign that water is condensing on the inside of your chimney and seeping outwards. One of the more concerning causes of this phenomenon is a cracked flue liner, which can lead to toxic fumes drifting into your home instead of through the chimney.
Screeching sounds coming from your faucets

You notice water draining slowly

An individual sink or shower draining slowly generally isn’t a cause for concern, with a slightly blocked pipe usually to blame. However, slow drainage through your house might indicate a clogged main sewer line, a much more sinister problem that is considered a plumbing emergency and requires immediate attention. Call out a professional if you suspect you have a clogged main line, as the situation can rapidly deteriorate and lead to flooding throughout your house.
Your toilet is gurgling

You spot holes in your decking

Your HVAC isn’t cooling the house properly

If your home’s HVAC doesn’t seem to be doing its job properly, or if you notice a persistent stale smell in the air, it’s time to call out an engineer. HVAC systems circulate air throughout your house, and it’s not uncommon for them to get blocked with dust and other bits of debris. Over time, these blockages can become severe enough to restrict the air flow, as well as imparting unpleasant odours to the air that does get through.
Hail damage to your shingles

A particularly vicious hailstorm can knock off the protective layer of granules that roof shingles are covered with. Once these granules are gone, the shingles themselves become susceptible to UV damage, eventually leading to leaks. It’s important to check your roof after a heavy hailstorm to assess whether there is any damage and – if there is – how widespread it is.
A breeze might indicate you need new windows

Windows allow you to get fresh air and natural light into your home, but they can also end up being weak points when it comes to insulation. If you keep feeling a noticeable breeze, even when all the windows are shut, it might be a sign that the sealant around one of them has degraded. Find out which window it is and get it fixed before damp and mould problems start to set it.
Your boiler is producing strange smells

Unusual smells coming out of your boiler can indicate a range of problems, many of them serious. The smell of burning indicates that the boiler is overheating, creating a potential fire risk. A rotten egg smell is even more concerning as it suggests a leak of carbon monoxide, an extremely combustible gas that can trigger explosions.
You have cracked floor tiles

You spot stains on your ceiling

One of the most surefire signs of a leaky roof is water stains that appear on your ceiling and run down the walls. If you spot these telltale signs you need to act immediately, as water damage can quickly damage the structure of your home and lead to mould infestations that are hard to get rid of. Unless you know exactly what you’re doing, it’s best to leave roof repairs to a professional.
The vents in your attic are clogged

Ensuring that your attic is well ventilated is critical for maintaining the health of your property, and clogged vents can have a number of knock-on effects. The vents in your attic are technically called ‘soffits,’ and their job is to suck in outside air which is then circulated through the house. If these soffits become blocked they lose the ability to inhale air, which can increase dampness in your house and will eventually lead to problems with mould.
Loose step flashing

Step flashing is used at the point where walls and roofs intersect, and it serves an important purpose, channeling water away from the wall and down the roof’s shingles. Unfortunately, the flashing sometimes rusts through or comes loose. When this happens, water runs down the wall instead, getting into your home and causing all sorts of problems.
Holes in the shingles of your roof

Small holes in your roof’s shingles are particularly pernicious, as they can cause rot for years before you realise there’s a problem. These holes are often left behind when antennae – which are drilled into the roof – are moved or replaced. When you move into a new property, it’s worth paying a professional to thoroughly inspect the roof. It’s a small expense that you could save you thousands down the road.
Plugs are hot when you remove them from an outlet

Electrical outlets occasionally develop faults that allow too much electricity to flow through them. If you’re finding that plugs are hot to the touch when you remove them from an outlet, you’re probably dealing with one of these faults. Call an electrician and don’t use the outlet until it’s been thoroughly inspected – dodgy outlets cause tens of thousands of fires a year in the US.
The grommets on your water heater are melted

Your water heater produces a number of harmful gases, the most concerning of which is carbon monoxide, an invisible killer that is responsible for over 400 deaths a year in the US. The toxic gases usually flow harmlessly out of your house via an exhaust, but occasionally a problem known as ‘backdrafting’ causes them to leak into your home. If you spot melted grommets on your water heater, it’s a surefire sign of backdrafting and you need to take urgent action.
You’re getting small shocks from an outlet

You spot aluminium wiring in your home

Your plants are dying

Dying houseplants can be an ominous sign that your home has a gas leak. High atmospheric levels of natural gases prevent plants from absorbing oxygen, causing them to wilt and eventually die. If your houseplants are starting to look a bit worse for wear and you know you’ve been looking after them, consider calling out an engineer to check for leaks.
You keep undercooking or overcooking your food

You’re nauseous for no reason

Some of the gases that are used to heat your home are toxic to humans, and prolonged inhalation can lead to a number or physical effects. The most common are nausea, headaches, dizziness, and irregular breathing. If you experience any of these symptoms, especially if they abate when you go outside, it’s best to err on the side of caution and call in a professional.
Your staircase is sagging

If your stairs are sagging, this could be a sign that the wood they are built on is shrinking. There are a number of reasons that this could be occurring, including damp, lack of ventilation, or proximity to heating pipes. If caught early enough, sagging stairs can often be repaired with the addition of some new wood, but over time the problem can become serious enough to necessitate an entirely new staircase.