Pressure washing: A job you can do?

A wet Sunday afternoon approaches. You’ve slipped on your decking about 30 times in the last two weeks and it’s greener than a plate of sprouts. What can be done? You look in the garage at your battered old pressure washer but retreat to the living room for some Sunday afternoon TV, “maybe next week you say”. 

Or maybe not. Can you really achieve the same outstanding results on your own? Or do you need the expertise and technique of a professional for a truly clean deck, driveway or patio?

Lets take a look at some things to consider before we spend our life savings on some fancy power washing equipment or call Lewis Cleaning Co. for a proper job.

  1. electric, petrol or diesel?
  2. how much power? 
  3. nozzle types
  4. detergent or no?
  5. technique
  6. aftercare

Ok let’s begin, there are countless models and manufacturers of pressure washers here in the UK with deals springing up left right and centre. It can be difficult to decide what you want but there are a few things that should help you decide what you need. Those being the job at hand and your budget. Everything else you can compromise on but if you can’t get the job done properly why even bother.  

Electric comes with some benefits specifically with portability and ease of use but not the power for heavy duty cleaning.  

Electric comes with some benefits specifically with portability and ease of use but not the power for heavy duty cleaning.  

Petrol or Diesel power washers have all the power you’ll even need!  

Petrol or Diesel power washers have all the power you’ll even need!  


Now naturally we want you to choose us to do power wash your patio or decking, not only because it’ll save you money in the short term but also (sorry to break it to you) we’ll do a better job than you ever could. We use our pressure washer every week and that experience really shows. Anyway back to the topic at hand. Let’s cut to the chase, a petrol or diesel powered pressure washer will definitely be your best option, they’re efficient, not connected to any power source (not sure if that’s called wireless or not) and powerful beyond compare. They do have a few caveats though; namely the noise they produce. If you have grouchy neighbours that will complain just for the sake of it then maybe it’s not for you. Also you need to make sure you have the fuel on hand to keep them running and they require a bit more maintenance than an electric model. But all those negatives pail in comparison to the power and efficiency you’ll gain from something with an engine. Personally I would only recommend an electric power washer for Sunday car washing and your garden path once a year. There are some electric models that have all the power of a petrol or diesel washer but usually come with the price tag to match.

At Lewis Cleaning Co. we only use high quality Honda powered petrol engines in our pressure washers. These benefit from over 3000psi of pressure and 12-15 GPM (gallons per minute) allowing us to get a great job done in the most efficient way.


How much power?

Quick tip! “try not to buy the pressure washer that has the most PSI as it’s not the only factor affecting cleaning potential. Always look at the GPM (gallons per minute) to determine how much water is pumped out at the desired pressure.”


There are a few things you should know if you do decide to go the petrol route before you start tackling the slime on your patio. When using such high powered equipment on your home some materials can withstand the pressure more than others. For example it wouldn’t make sense to unleash the full PSI’s of your pressure washer on that delicate patio furniture or even your decking compared to a hard stone or concrete patio that can take the pain.

We’ll make it easy for you here with a few tips on how much pressure to use on what materials.  

  • Decking - wood is quite a soft material, and any wood in contact with moisture makes it more susceptible to damage as the fibres in the wood are raised making it easier to splinter. We recommend not using pressures over 2000psi although this is based on the average gallons per minute of your washer being around 3-4. When cleaning always start your pressure washer away from the surface and slowly move the jet closer until you are achieving the required cleaning results. Don’t go closer than around 20 inches so as to not damage the wood. Try using a sweeping motion whilst keeping the wand the same distance away from what you’re cleaning so you get an even clean. Use this same method for the cladding on your home. Although drop the pressure down to around 1000psi if you’re cleaning uPVC. 


  • Patio, stone, concrete - being much harder this material can withstand 4000psi and over and is generally quite a forgiving material to clean. If you have an oscillating nozzle or even a high powered jet nozzle this will work great. Especially on tough oil stains that you’ll pick up if your park your car on the drive. Once again try to keep the nozzle at an even distance from the surface to avoid a patchy look.  


  • Render - the render on your home is very delicate and might be best left to someone who knows what they are doing. Someone like Lewis Cleaning Co. with experience cleaning many types of render on residential and commercial properties in Cheltenham and Gloucester. We recommend not using any more than 1500psi and keeping a safe distance of around 1ft from your render to avoid pulling chunks off your house. 


Nozzle Types

 There are many different types of nozzles that work for specific tasks. You can even buy patio cleaners that resemble a floor polisher. The wand that comes with your pressure washer will most likely be good enough for most tasks and some even have multi functions like the Karcher models although these electric powered power washers might not have the required power to get the job done in a reasonable amount of time. 

So how does the nozzle work. Well let’s say you are using your standard garden hose pipe. You don’t have that much pressure and you can’t reach the roof of your car to rinse off the soap. What do you do? Well it would make sense to block off a portion of the end of the hose with your thumb so the pressure builds up and the water shoots out further. It’s the same for your pressure washer. If it attach a nozzle that reduces the space the water can exit on then you’ll get a finer jet and a higher pressure which is better for cleaning off tough stains compared to a more spread out jet  

Our pick for a good combination of nozzles would be first the oscillating jets for high powered cleaning. This works on all hard surfaces like patios and concrete and on some hardwood decking. It is mighty powerful though, especially on a petrol or diesel powered washer so use with caution and maybe even test on an inconspicuous area in case you mess up.

if you are looking for all round cleaning then the fan jet is useful for washing your car, cleaning the decking or patio and even washing the cladding on your house and if your budget is tight then go for this one. It’ll take a bit longer than the oscillating jet but it’s slightly more versatile.

There are many more nozzle types but we thought we would highlight the ones you’ll definitely need. 

Take a look at this awesome chart to help you decide what shape jet you need to clean safely.

Be careful! Some nozzles don’t work well with detergent.  (Image from consumer reports)

Be careful! Some nozzles don’t work well with detergent.  (Image from consumer reports)



It really depends on what you are cleaning. If you’re cleaning concrete or stone it’s not really necessary unless your washer isn’t removing the dirt effectively in fact an after treatment of your stone is recommended to increase the amount of time it stays clean for. Products are also available to waterproof the stone to keep the green at bay and create a slip free area.

For your decking or cladding on your house we recommend a product called Virosol. It’s a great product that’s also eco friendly but really lifts the algae and dirt from the wood. Just leave it on for 15 minutes without letting it dry out (bit less on a sunny day) and get to work with your pressure washer at the correct pressure and the right nozzle might we add.

In terms of aftercare, anything that is waterproof and protects wood should be fine to get the job done. Lewis Cleaning Co. can provide aftercare services if required, we only use the best and longest lasting products to leave a great finish and reduce the amount of cleans you need to maintain your property.  


Technique is second most important to getting great results on your drive or decking. Working systematically enables thorough results and leaves you satisfied knowing you’ve done the job well. First and foremost make sure you’re always keeping a constant distance between the pressure washer nozzle and the surface you’re cleaning this will ensure whatever you’re clean has an even finish, and if you’ve tested in an inconspicuous area you’ll know how close to go before you start ripping the decking to pieces. Second if you are using a detergent or stain removal chemical we recommend getting a cheap garden sprayer for even coverage. It’s the same principle as jet distance but instead the higher concentration of chemicals will remove more dirt and therein leaving an uneven finish. Lastly have a plan...especially if you know you won’t finish the job in a day. Not only will this save you time but it will be much easier to pick up where you left off. If your decking or patio is really dirty it’ll be pretty obvious where to kick off again though.


Here at Lewis Cleaning Co. we recommend getting your decking cleaned just after autumn and before winter. Allowing the leaves to fall and the worst of the algae to show up. Then we zip in and blast it all away leaving a grippy surface that’s safe to use until the next autumn. In some cases it may need to be cleaned once every 6 months depending on your environment and how many trees are near. we provide maintenance plans in the Cheltenham and Gloucester area to keep up with cleaning your property without breaking the bank.

Final tips

There are a few last things you should know before you go out and get your own pressure washer and all the accessories. We know this is expensive equipment and if you don’t feel confident in tackling such a task then give us a call for advice or a quote on the job. 

You should check the pressure on your outdoor tap before you make any purchases. This can affect what GPM and PSI pressure washer you can actually use efficiently. Most manufacturers require that the PSI of your tap should be no less than 40PSI. Although some of the more powerful and expensive petrol models can draw water from a barrel into their own pump taking out the need for high pressure from your tap, but it still will need enough flow to fill up the barrel before your power washer uses up the water as letting the pump run dry for too long will cause unknown damage and definitely void your warranty. 

Try to avoid using your pressure washer in direct sunlight. Especially if you are cleaning your car. If you are applying detergent the sun will dry it out and bake it onto your car not only damaging the paint but making it difficult to remove. On your decking leaving the detergent on can have irreversible affects decreasing the lifespan of the wood and meaning that when you seal the wood after washing you’ll actually be sealing the detergent in there as well. We recommend cleaning after it’s rained as the surface will already be soaked ready for cleaning.

so what are you waiting for! There’s everything you need to know about pressure washing. Even if you don’t want to face doing it yourself this article might answer some of the questions you have when we come to clean your patio, driveway or decking. At Lewis Cleaning Co. we try to be as flexible with our time as possible booking in customers within a week no matter the job. We always provide commercial pressure washing in Cheltenham and Gloucester. Please contact us to find out more about this service or to request a free no obligation quote at a time convenient for you. Or if you prefer send us a message with a few pictures to 07187 900927.