50 Reasons Why You Should Never Pressure Wash Your House

50 Reason Why You Should Never Pressure Wash Your House

Here are fifty reasons you should never pressure wash your house. Fifty ways that pressure washing unwittingly does more harm than good.

Everybody pressure washes their house in some way shape or form, at one time or another. Very few people know that the way most people do it, however, is NOT good for your house and poses further risks.

You may well just be going with the crowd, and that’s understandable, we all do it at some point. It has to be said however, in this instance, the crowd is wrong, very wrong. It must also be said that you could be highly likely to cause big damage to your house that you have absolutely no idea about.

Pressure washing is usually the first step when you are getting a new paint job to the exterior of your house, so you see a lot of painters doing it and doing it wrong.

You may be thinking of cleaning your decking, patio slabs or patio furniture with a pressure washer. Or even using a pressure washer to clean your garage, shed or outhouse too. Whatever it is that you’re thinking of cleaning with a pressure washer, it’s probably best that you stop.

At least until you’ve finished reading this to see why it’s NOT a good idea to use a pressure washer on your house. It’s not only unknowing and eager homeowners that are doing it wrong too, but it can also be the professionals. It’s often a favourite method of preparing surfaces for painters to work on.

You get painters and even the pressure washing companies themselves walking away from a house with a clean exterior, but the work they have done has caused untold damage inside the walls of the house and in other more hidden places.


Ease Into the Job

should you pressure wash house

should you pressure wash house

It Leads to Water in the Walls

This can be some of the worst kind of damage you can do with a high-pressure washer to a house. Some pressure washers propel water at pressures starting at 1500 psi which isn’t too destructive, but they can go upwards of 3300 psi, which will blast right through solid wood, asphalt, and even concrete if they’re close enough.

If you have a house with any kind of wood exterior or siding (clapboards, shiplap, board and batten, shingles, etc.) there is a very high chance that washing your house with a high-pressure washer will send water up under the siding, potentially soaking wall cavities, insulation, wiring, flooring, plaster, etc. Nothing is beyond the reach of a powerful water gun.

Once the water is inside the wall, it can be very difficult for it to evaporate.

Often, in the painting process, a house is pressure washed first, then caulked and patched and then finally painted. Essentially, the water is soaking into the inside of the walls and then being sealed in with a fresh coat of caulk and paint.

It’s possible to end up with mouldy insulation, crumbling plaster, and cupped flooring all from a pressure washer’s work. Nothing in your walls likes to be wet so keep it dry.

It Causes Missing Mortar

People often think that since they have a brick house, they are safe to pressure wash. Unfortunately, this isn’t true. Older bricks and mortar are often softer than the newer stuff today and can be easily blasted away with high-pressure water.

Brick houses can end up with the mortar almost completely blasted away by pressure washing. And the expense of repointing a brick house is probably 10 times what it would cost you to wash your house.

You End up with Gouged Wood

When pressure washing in preparation for a paint job, a lot of people will get right up close to the surface to try to blast any loose paint off. They often succeed. Then they have 3000 psi water blasting straight into bare wood. It digs holes in the surface and loosens up the wood grain up damaging the siding.

Unless you intend to carve your name into the side of your house with water, this is another reason not to pressure wash!

It Spreads Lead Paint

It’s always there lurking beneath the surface of an older house. We want it all gone, but removing lead paint with high-pressure water is not the solution.

It causes lead paint chips both small and large to be sprayed all around the garden and get mixed into the soil or the kids play area, where the kids can potentially ingest it.

It Can Cause Damage to The Render of The Building

The high-water pressures can damage the render by breaking the skin and then penetrating behind the skin of the render or paint and then blowing it away from the wall. Causing a much more expensive problem to fix.

It Only Leaves Surfaces Looking Clean

Pressure washing doesn’t actually clean or kill organic spores, it just aggressively removes stains and doesn’t treat the root cause of a problem.

To prevent regrowth the application of an appropriate cleaner such as those similar to the ones used in soft washing are required. This needs to be sprayed onto the surface to be cleaned, agitated with a brush & allowed to work before rinsing away.

It Leaves You With Patches

Assuming that you haven’t actually caused damage to any of the surface of the house, you can end up leaving patches or yet worse, stripes, due to an inconsistent angle or distance of the pressure washer near the surface.

A Pressure Washers Can Come With Multiple Jets

Whilst ordinarily this shouldn’t pose too much of an issue, most of the very basic pressure washers come with just one lance and nozzle. Some of the more expensive models can come with lances and nozzles that have different strengths and shapes of jet spray. These include:

  • A variable-fan jet: This is ideal for cleaning delicate surfaces, such as cars, decking or chipped areas of patios, as it can allow you to adjust the force of the jet from a focused point to a gentler broad fan.
  • A rotary jet: Best for disintegrating ingrained dirt from patio slabs, but way too strong for delicate surfaces such as cars or decking.
  • An angled lance: This can be used for cleaning the underside of cars and garden furniture.

If your pressure washer only has a fixed jet, move it further away from the object you’re cleaning to reduce the force of the spray and avoid damage.

A Pressure Washer Can be Destructive

In lesser experienced hands, a pressure washer can cause untold damage. It can destroy window screens, cause leaking in window seals if the seal gets damaged, and more.

It Can Remove More Than You Expect it to

For example, it can remove paint, which is all well and good if that is all you are trying to remove. However, if you were only planning on cleaning the brickwork on your house for example, you’ll now be faced with repainting any painted wooden surfaces as well.

It Doesn’t Always Remove What You Want it to

Sometimes, no matter how high you turn up the pressure on the nozzle or whatever other methods you try as well, stains just won’t come out and it can cause damage if you try too hard. For example, if a driveway hasn’t been sealed properly and it has oil spots on there, you may as well just forget it. There’s nothing you can do with pressure alone to get it out, no matter how high you have the jet turned up.

This also includes fertilizer, rust and stains from tree sap for example; they also present a nearly impossible job to remove from a driveway. Mould and mildew will come right up but these types of things will also always leave some kind of mark or residue after they’re gone.

The Consequences Can Cost You a Lot of Money

Be sure to protect your assets before you start. Plants, cars and other outdoor items remain vulnerable to the pressure stream and chemical runoff if you are using chemicals for any particularly tough stains. It is definitely worth covering them or as a minimum rinsing them with water before, during and after your cleaning is finished, this will dilute most chemicals. You want to get it out of the way at the start because dry leaves will absorb chemicals more easily than wet ones.

should you pressure wash house

It Can be a Dangerous Activity

For most pressure washers, the power output is measured in pounds per square inch (PSI), many pressure washers are capable of as much as 3,000 PSI. This amount of pressure is more than enough to breakdown cement and cause significant injury to the operator.

There Can be Multiple Safety Considerations

You should be careful to never point a pressure washer at people or pets. You should always be sure to wear protective goggles, as well as a pair of gloves, safety boots and long sleeves while operating one.

The Weather Can Cause You Significant Problems

As you are more than likely pressure washing outside, you should pay attention to the weather forecast. If it’s forecast for a windy day, pay close attention to which way the wind is blowing to prevent the water and other debris from spraying back at you.

There’s a Technique to it, You Need to Get it Right

If you feel you really must pressure wash your house, it’s massively important that you do it properly. That means where you start and finish matters. For example, it would probably be prudent to start at the top and work your way down, avoiding all electrical outlets, avoiding direct contact on the windows and screens. You should also be fully aware of your surroundings and be especially cautious using a pressure washer around overhead wires, electrical panels and exterior lights.

It Isn’t Cheap to Buy a Pressure Washer Suited to The Job

If you’re looking to buy a residential standard electrical pressure washer, you can expect to pay anywhere in the region of £60 to upwards of £200. Then there are petrol-fuelled pressure washers which generally have far more power than electrical models, and these can range from £300 to well over £1,000. Much more powerful commercial pressure washers, used for large jobs would start at around £1,000.

It Isn’t Much Cheaper to Hire Either

If you decide to pressure wash your home or parts of it yourself, to hire a pressure washer is typically around £25 to £100 a day, depending on where you live. This can elevate the cost of what would seem a relatively simple DIY job exponentially.

It’s Also an Expensive Job to Outsource

To get your decking cleaned alone can typically cost between £0.25 and £1.50 per square foot. This price is often much higher if you have multi-level decking, and some companies may even charge you extra to clean the decking railings and steps.

If you’re thinking of having your decking pressure washed, consider having it sealed or stained as well. This is to protect the wood and extend its life. Hiring a professional, who will clean and seal your decking can cost from £1 to £5 per square foot, so you could be looking as little as a few hundred pounds, into the thousands, depending on the size of your decking.

Power washing businesses are generally not required to be licensed, however, they should have relevant insurances for your area, so before hiring a professional to complete the work on your behalf, take time to read customer reviews and ask for references.

It’s also worth noting that if a professional power washing company will be expected to work in an area with plants or any other items that could be damaged, ask them what kind of cleaning solutions or other products and chemicals they will be using and whether the could damage plants or soil, and see what steps you can take in advance to help to prevent this. Avoid a home decking cleaning disaster by completing your research and doing your due diligence.

It’s not All Just About The Pressure

People often talk about PSI [pounds per square inch] a lot when discussing a pressure washer, and while that is part of the question to consider when getting hold of one, you really want to be looking at the amount of water flow and looking at this in gallons per minute or GPM.

A machine with a water output of 5GPM and at 3,700 PSI will clean much better than a machine at 4 GPM with a much higher pressure at 4,000 PSI.

It’s also worth making sure that the washer can dispense cleaning products as well as plain water. By all means, you could clean your driveway without any cleaning chemicals at all, but it’ll take much longer and it just won’t last as long. If you use a little chlorine, for example, the concrete on the driveway soaks it up and helps to keep mould and mildew and other growths from coming back.

You Could Risk Overdoing It

The key to effective DIY is to make sure you don’t overdo it. If you have decided to pressure wash your home or decking yourself, don’t go overboard once you get started, and then you should build into it slowly, starting with the lowest setting and work your way up to higher pressures. If you find yourself facing stubborn stains. You could end up being left with a huge repair bill, or worse, having to pay to completely overhaul and renovate something.

Pressure Washers Can Be Very Dangerous in Untrained Hands

A pressure washer, when being operated improperly, can present a significant danger to both the user and people around the area. The high-pressure water jets could also damage property as well as potentially causing serious injury.

We already know that a pressure washer, especially a newer one, can take the paint right off the house. Therefore, you should probably consider wearing eye and ear protection. Power washers are a lot stronger than a standard garden hose that most people are used to. If you’re not careful, you can seriously injure yourself or others with the force of the water.

Some Jobs Are Just Too High Up to Start With

While it’s possible and feasible that you could do some basic pressure washing around your property, at some point, when the going gets tough, you’re going to need to call in one of the professional power washing companies located near you. Realistically, there’s just too many things you can get yourself into trouble with. Especially if you take on something too big.

If you are contemplating doing a pressure washing job, especially a big job, it might be best to call in someone with experience from the start. It would definitely be safer to call in help for any job that is higher than one story, or even one that involves a roof. A roof can be dangerous to work on, and it’s also very easy to damage.

When it comes to houses taller than one story, specialist companies will have the equipment that can go as many as three or four stories high without the need for an actual ladder, making the job far safer for them to complete.

Not All Pressure Washers Are Equal

It’s worth remembering that not all pressure washers are equal, and they are not all suitable for every outdoor job there is. It’s very important to use this tool properly, remembering it is still a tool.

Ensuring you use it safely so you ensure satisfying, damage-free results. Whether you’re in the market for a new powerful, game-changing pressure washer or you already have one in your home-care arsenal, make note of these best and worst practices when it comes to using it so that you can be sure to get the most from this lean, mean cleaning machine.

You Need to do Your Prep Beforehand

If you don’t have an adequate water supply to start with, your pressure washer will fall far short of your expectations in terms of efficiency. First, it’s good to test the water flow from your hose by timing how long it takes to fill a five-litre bucket. If it takes two minutes or less, you’re in a good spot and you’re good to go. If it takes much longer than that, it shows that there’s potentially not enough water flow to operate the washer effectively.

Once you’ve established whether you have the sufficient water flow that you need to feed your pressure washer, you then need to check that the connections are secure wherever the tool attaches to a hose or accessory. That way you can be more assured that you are operating the machinery as safely as possible.

It’s Easy to Underestimate its Power

A pressure washer’s biggest strengths, it’s speed and power, can make this tool as dangerous as it is efficient. A Case in point: The water stream from even those models with a PSI on the much lower side is forceful enough to cut through human skin.

Save yourself and your property from harm by following the manufacturer’s safety guidelines, then be sure to grip the wand tightly to avoid any recoil from when the pressure kicks in, and start on the lowest pressure setting.

Technique, Technique, Technique – It Matters!

As a basic starting point, it’s important to start by working in sweeping motions so that you’re never concentrating the tool’s power in one place for too long. Always aiming the nozzle away from people, pets, and your prize peony bush.

Don’t Use One Nozzle Tip for Every Job

You can fit a pressure washer with a variety of nozzles that produce everything from wide-spray patterns to narrow streams ensuring you can better harness the water for the job at hand. As a general rule of thumb, it’s worth noting the narrower the spray, the more force it delivers. A wide, 40-degree nozzle works very well for general washing, such as loosening dirt on different wooden decking, cleaning building sidings, and rinsing patio furniture.

A 25-degree nozzle tip will tackle dirt and grime on concrete, patio slabs and other types of masonry. Zero or 15-degree nozzle tips concentrate intense pressure on a small area, making them very useful and efficient for removing stubborn stains from wrought iron dancing for example.

Adjust Your Spray’s Angle for Best Force

When stubborn stains do require a maximum pressured cleaning power, you want to do your best to keep the pressure washer’s nozzle perpendicular to the grimy surface. Sounds easy enough, right? Well, it is, until you need to reach the underside of a patio table or the siding along the top of a house.

Ease Into the Job

A blast from a pressure washer that is too direct can damage even the surfaces that you’d expect to hold up well to a pressure washer, so you should always start with a light touch. For example, when cleaning a siding, where a pressure washer excels at cleaning most types of wood, stand too close and you risk blasting away some of the paint or ruining a softer wood like cedar for example. For best results in pressure-washing, position yourself approximately 10 feet away from the surface you’re about to clean, turn on the water, then step forward slowly, until the spray is just forceful enough to remove dirt, and not strip away paint exposing bare wood.

You Shouldn’t Use a Pressure Washer to Clean Everything

Even when exercising extreme care and using the lowest possible pressure, not all items are suitable for pressure washing, even more so if they already show some signs of wear and tear. An example would be, while most paint jobs can withstand a moderately strong spray, a thin clear coat or scratched exterior should be cleaned using lower water pressure.

should you pressure wash house

should you pressure wash house

There are Techniques When Using Detergents

Caked-on gunk comes off much more easily if you soak the surface first with water, with or without detergent, and then let it sit for a few minutes. When using detergent, wet from the bottom up, using sweeping horizontal motion to help to prevent streaks caused by the excess runoff. To rinse, work the opposite way, working from the top down so you don’t miss any cleanser.

You’ll probably Damage Your Roof

Should you decide to use the pressure washer on the roof, you’re probably going to run into trouble at some point. Consistent use of high water pressure on the roof can lead to several problems, such as:

  • Decreasing the longevity and life expectancy of roofing materials by up to three times more than their actual life expectancy.
  • Breaking any bonding or adhesive materials between the shingles, which in turn can lead to damaging any underlying fabric of the roofing material.

Power Washing Can be Very Inconsistent

A power washer’s output pressure needs to be regulated accurately. If it is not, the pressure that is released could severely damage different materials. Nozzle size is also a factor. Also, when an improper nozzle is used, any spray that is released could affect the surfaces. Any kind of real spraying should be done from the top down and not the bottom up. When there are other features on a roof for example, such as vents, skylights, flashing, chimneys, solar panels and any other items, high-pressure water could compromise the sealants on any one of those elements, plus create leaks.

It Can Damage Concrete and Pavers

When using a power washer to clean concrete, bricks or paving slabs, it is possible to cause significant and visible damage. This is usually in the form of pitting, lines or general surface degradation. It is also possible to damage the mortar between bricks and disperse the joint sand between paving stones. In the case of concrete slabs installed less than one year ago, they are more likely to be damaged than older slabs.

A Power Washer is Only as Efficient as its User

Power washers and their efficiency completely depend on the person using it. If you are a skilled operator, then the whole process of cleaning becomes much faster and more effective, taking less time to get the work done.

Risk of Tarnishing Surfaces

Effective power washing generally uses chemicals, therefore some surfaces might get ruined as this may cause a reaction

Damage to Your Sidings

While it is possible to wash a wooden siding correctly, there’s also a very good chance that water will find its way up and under the exterior surface if you are using high pressure. From there, water can damage insulation, electrical wiring and can spur mould growth. A high-powered pressure washer can also be powerful enough to dent aluminium and vinyl siding.

You will Cause Damage to Electrical Panels and Meters

Even if they are on the exterior of your home or in your yard or garden, fixtures that are housing electricity should not be pressure washed. Though they can withstand heavy rain, pressure washing could force water into cracks and crevices and cause damage, resulting in a need for costly repairs.

Damage to Older House Bricks

Weathered house bricks and other landscaping surfaces utilising mortar can be damaged by pressure washing. Any loose materials, especially on an older structure, will be blasted away by pressure washing, especially on a high setting and over a sustained period of time on a lower setting.

Painted Surfaces That You Want to Stay Painted, Won’t

Pressure washing can easily chip away at the paint on most surfaces, so it’s worth only using a low-pressure flow of water to wash painted items such as a porch floor or painted outdoor furniture.

It’s Not Just Regular House Fittings That You Could Damage

Items that are attached to your home, such as lights, post boxes, hose reels, gutters, phone connection and internet boxes, and decorations, will all need to be removed first or avoided somehow. A pressure washer can break right through a fancy light fixture that’s on the side of the house, causing damage to both the fitting and the fixture. Always make sure all outside lights are switched off before you begin spraying.

should you pressure wash house

should you pressure wash house

There are Even More Safety Considerations

As already mentioned, your safety needs are to be addressed first when using a high-powered pressure washer. Water and electricity are never a good mix, so you will need to avoid electrical outlets on your home’s exterior.

If you need to use a ladder to reach high spots or a second floor, make sure the ladder is sturdy enough and at the proper angle and make sure you have someone to help to keep the ladder sturdy. You will need two hands to be able to operate a pressure washer which can have some kickback when the water strikes the house. Also, it’s worth considering that standing on a roof to reach higher sections of your home is never a good idea.

Be Aware of Your Surroundings

You need to fully check the area that you may be about to work in. Homeowners need to be aware of overhead power lines and other hazards.

Not All Chemicals Are Created Equal

Some high-pressure cleaning chemicals have specific uses. Some are created exclusively for wood, and others for bricks. Mixing chemicals is not safe, and is unlikely to give the results that were originally sought after, and can lead to undesirable results; such as sticky or uncleaned bricks. It would be worth changing chemicals from job to job to use the right chemical for the job in hand.

There is a Risk of Electrical Shock

This one might seem pretty obvious, but it is worth noting here that a pressure washer is an electrical device. It is also an electrical device that uses water. If you are not skilled in operating it, this can be a dangerous combination. It would be recommended to find out exactly how to make sure the machinery is properly grounded and assure safe operation.

You May Get the Cleaning Order Incorrect

If it’s your first-time pressure washing on a big project and you are inexperienced, you may not be aware that there is a proper order to clean your home’s exterior. By washing the windows before you wash the brickwork on the side of your home, you can undo your hard work, spreading grime from the brickwork back onto the windows as you clean. As a result, you waste the cleaning solution and your valuable time.

The Wrong Equipment is Used For The Job

A good quality pressure washer is needed to perform different types of washing application. However, many homeowners do not know what type of equipment is best for their project. As a result, money can be wasted by trying out different equipment then receiving less-than-ideal first-time results.

The Cleaning Solution Has Been Omitted

Water alone is great for rinsing a surface that doesn’t have too much build-up of grime, but for cleaning projects that involve pressure washing, an appropriate cleaning or detergent solution is often needed. The detergent increases the efficiency of the washing process significantly.

At times, when a homeowner fails to add a cleaning product to the washing solution, they may try to compensate for the poor cleaning results by turning up the pressure of the equipment. This can then lead to property damages, without actually increasing the effectiveness of the cleaning.

Additionally, water alone is not going to kill mould or other growths. Instead, it simply redistributes it over the surface, potentially leading to the mould spreading. Mould related repairs can be quite costly.

The Pressure Washer Loses Pressure

There can be a whole number of problems that cause this symptom, such as a blocked nozzle or water inlet, inadequate water supply, air in the inlet water supply hose or the pump. Either way, investigating it and then fixing it is going to lead to frustrations and added time to what you thought would be an easy job.


So here you can see, while pressure washers can be an impressively efficient tool for cleaning your home’s exterior. They can also cause more harm than good if misused or used ineffectively by an untrained or unwitting individual.

We hope this guide helps you get all the knowledge you need around pressure washing and helps to prevent any mishaps!

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