Pressure Washing a Driveway? Read This First
We all want to keep our driveways looking sharp, and what better way to clean the concrete than with a pressure washer? Before you get the pressure washer out, there are a few things you need to know first. Don’t go away with the idea that concrete is so tough, you can’t damage it.
If you use too much power on your concrete driveway, you’ll end up with a drive that looks like the Nazca desert at best and the cratered surface of the moon at worst. You see concrete is tough, but it’s not that tough. Once you start pressure washing, you have the potential to do some real damage.
You also have the potential for great cleaning power in a short time. As long as you use the pressure washer correctly, your concrete drive will be clean in no time, and without any damage. The first thing you need to know is nozzle power.
What Do The Coloured Nozzles Mean And When Should You Use Them?
With most pressure washers you’ll be supplied with 5 nozzles, all with different colours. They are used for different applications and using the correct nozzle will not only make the job easier and faster, but it will also prevent damage. So what are they for?
- Red nozzle
The red nozzle is the most powerful nozzle, it has a 0-degree angle, which concentrates the water jet to almost a pinpoint. Use the red nozzle on really tough stains, but never concentrate on one spot as this nozzle will definitely cause damage.
- Yellow nozzle
The yellow nozzle is still a very powerful nozzle but not as intense as the red nozzle. It has a 15-degree spray angle and is used for heavy-duty cleaning and stripping paint. You still shouldn’t point at one spot for too long because this nozzle is powerful enough to cause damage too.
- Green nozzle
The green nozzle is used for general cleaning tasks, with its 25-degree angle spray, it’s powerful for most cleaning operations. But not so powerful as to cause damage, unless you concentrate the jet at one spot for too long.
- White nozzle
The white nozzle has a 40-degree angle spray and is used for delicate surfaces that can damage easily. It’s also the best nozzle to use for rinsing away detergents when cleaning cars etc.
- Black nozzle
The black nozzle is the detergent nozzle, it mixes water with the detergent and due to its 65-degree angled spray, it is the most gentle spray of the 5.
There is also the turbo nozzle, which gives the lifting ability of the green nozzle combined with the blast power of the red nozzle, it blasts as it rotates.
Some pressure washers don’t use the coloured nozzle system, they use a variable nozzle which is all 5 colour nozzles in one. You change nozzle power by twisting the nozzle to the one you need.
Now we’ve looked at the nozzles, let’s have a quick word about safety.
How To Safely Pressure Wash A Concrete Driveway
This section is all about safety-personal safety and the safety of your house and it’s fixtures and fittings. Let’s start with personal safety, before using a pressure washer you should always:
- Wear protective clothing
Keep arms and legs covered, the pressurised water from a pressure washer is capable of lacerating skin. No shorts or tee shirts.
- Keep feet covered
Wear boots or closed in shoes, no flip flops or open toed sandals unless you want to lose a toe.
- Protect your eyes
Wear goggles to prevent dirt and debris damaging your eyes from the high-pressure spray.
- Wear Gloves
It is so easy to get injured with a pressure washer, and so easy to prevent hand injuries just by wearing some protective gloves.
- Protect your hearing
Some pressure washers can be extremely noisy, if you have sensitive ears, wear some ear protectors or noise resistant earphones.
- Be aware of any trip hazards
Remove any pot plants, toys, tools, electric cables, or anything else you could trip on.
Now let’s think about protecting your house and your possessions. Before you start pressure washing your drive, always:
- Protect windows and doors
The high-pressure water that cleans your drive can force any dirt or debris up and onto windows and/or doors. If the area you’re planning to clean has a window or a door close by, cover it in plastic sheeting taped up with masking tape.
- Think about plants
You’ve probably spent a considerable amount of money on the plants that surround your driveway. The detergents used for cleaning drives can damage those plants and in extreme cases kill them. Cover these plants with plastic sheeting and secure using rocks, or other heavy weights to prevent the plastic blowing away.
- Cover electronics
Any electrical devices outdoors like intruder lights, alarm systems, outdoor power sockets, air conditioning units, meters, junction boxes etc should be covered to protect from water damage.
- Remove the bins
Rubbish bins and recycling bins can be a hazard when pressure washing, remember to remove them from the area you are going to clean.
- Children and pets
Pets and children all want to be outside on a nice day, even more so when there’s the added spectacle of a pressure washer show to watch. Be aware of where they are and move them to a safe place where no harm can come to them from the pressurised spray or the flying debris.
- Move any vehicles
As you’re cleaning the drive this might seem obvious, but pressure washing at the wrong power level can cause damage to the body work of a car. Make sure your vehicles and any boats are safely out of harm’s way.
The Correct Way To Pressure Wash A Driveway
We’ve covered all the basics now, we know which nozzle to use, we’ve covered personal safety, property safety and children and pets safety too. Now we need to check a couple more things and we’re ready to go.
What Is The Driveway Constructed From?
The construction of your driveway will make a huge difference into which nozzle you use and also the technique you use for cleaning too,.Driveways are usually constructed from one of these 6 types. They are concrete, brick, cobblestone, block paving, asphalt or gravel. So what are the maximum pressures and nozzle type to be used for each surface type?
|Surface material||Maximum pressure and best nozzle|
|Concrete||3000 PSi Yellow nozzle (with care)|
|Brick||1500 PSi Yellow nozzle (with care)|
|Cobblestone||1500 PSi Green nozzle (with care)|
|Block paving||1500 PSi Green nozzle (with care)|
|Asphalt||1500 PSi Green nozzle (with care)|
|Gravel||Never use a pressure washer on gravel|
Now let’s get into cleaning the driveway.
How To Clean A Driveway With A Pressure Washer
So now we’ve determined what material our driveway is constructed from, we can get on with cleaning it properly. Here’s our easy to follow step by step guide to pressure washing a driveway.
- Sweep the driveway clean
With a yard broom clear all loose dirt and debris from the driveway.
- Treat any stains
If there are any oil or grease stains on the drive, treat with an appropriate degreaser, following any instructions on the bottle.
- Start the pressure washer
Start by connecting the garden hose to the pressure washer and turning the tap fully on. Then pull the trigger on the wand and allow the water to flow for at least 30 seconds, this will remove any air in the system. Then turn your pressure washer on.
- Add suitable pressure washer detergent
This step is optional, but advisable. First wet the surface with the white nozzle, then fit black nozzle and apply detergent to the driveway. Allow to soak for around 15 minutes.
- Rinse off the drive
Using the correct nozzle and pressure setting, rinse all the detergent away starting from the top of the drive, nearest the house, and work down towards the pavement.
- Seal the drive
After the driveway is completely dry, apply a sealer to protect the drive and prevent any serious staining, weed regrowth or damage.
Frequently Asked Questions
Before pressure washing your driveway spray a degreaser on to remove any oil or grease stains.
You should pressure wash your driveways to keep them clean and safe.
You do need to seal your driveway after pressure washing if you want to preserve your driveway.
It is worth sealing block paving to preserve it and keep it clean and damage free.
A pressure washer will remove concrete sealer if it is used on high-pressure and with the red nozzle.
After washing concrete it should be left to dry for 2 to 3 hours on a sunny day before sealing.
To pressure wash 1000 square feet should take around 30 minutes.
After the driveway is sealed you should stay off it for at least 24 hours, longer in cool weather.
Concrete driveway sealer lasts on average between 1 to 3 years.