How To Clean Block Paving With A Pressure Washer

How to clean block paving with a pressure washer

Do you want to correctly learn how to clean your block paving with a pressure washer? Pressure washing block paving seems a simple task but it can do long term damage to block paving if not done correctly .

We have provided a free guide with tips and good advice on how to clean your block paving with a pressure washer.

We have also included plenty of best practices that professional cleaning contractors use. They are worth reading before you begin to clean your block paving driveway or patio.

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Tips to note before you begin pressure washing block paving

Always begin by giving your block paving a good sweep. Use a stiff broom to remove any debris such as stones, old cement and general loose dirt. This stops the debris becoming a projectile when hit by the jet of water. It also stops it having an abrasive effect on your paving blocks. It also allows you to fully inspect your paving before you begin pressure washing your block paving.
Look for any oils stains that need removing. Apply a cleaner to any oil, petrol and grease stains on your block paving surface before you clean your paving. This makes it easer to remove the stain with a pressure washer. Remember any untreated stains will show up once your paving is cleaned.
Think about applying a cleaner first before you use a power washer. This will make it much easier to remove the dirt from your paving surface. You could use bleach to remove the dirt or why not consider using a more environmentally friendly cleaner such as an apply and leave paving cleaner. After you have cleaned your paving blocks why not consider applying one of these cleaners. They kill all your moss & algae spores so stop greenery re-growing for up to 6 months afterwards. They also help keep your paving cleaner for longer.
Does any of the block paving need to be relaid because it has sunk? This could be done after you wash your block paving or before. It's up to you. We have a helpful guide on relaying sunken block paving here.
Consider applying a weed-killer. When moss and weeds on your patio or driveway are dead it makes them so much easier to remove them from the block paving. Try to apply a weed killer at least a week before you clean your block paving with a pressure washer. After you have applied a weed killer to the weeds, moss and algae wait until the weeds and moss show signs of being dead. You can tell when your moss or weeds have died because they will become brown and dry.
Remove weeds, especially larger weeds before you use a pressure washer. Removing weeds and moss before you begin can cut down on the amount of time needed when pressure washing block paving. You should always remove larger weeds either by hand or using a weed removal tool. Larger weeds can be difficult to remove with a pressure washer and can do permanent damage to your underlying sand if you reply on the force of the water jet to remove large weeds.
Consider using a rotary head attachment to contain the water jets and stop splashes. These attachments for your pressure washer are ideal if cleaning in a confined space or if you are close to your neighbors home.

Step-by-step guide on how to clean block paving with a pressure washer.

Remove as much weeds and moss from the surface as you can but especially larger weeds before you begin
Start the cleaning process in a corner of your driveway or patio above the run off area of the dirty water. This is so that you don't have dirty water running on to your cleaned area of paving.
Always power wash the driveway or patio working away from, and not towards buildings, cars and neighbours property unless unavoidable.
Work your way with the power-washer across the paving trying to avoid splashing any doors and windows with dirt. If you do get them dirty make sure you clean up by rinsing down as you go. Therefore not having to go back and clean them afterwards.
Remember to rinse down house and garden walls that will be splashed with dirt as you clean your paving. If you want to avoid splashes when pressure washing block paving why not consider fitting a rotary head cleaning brush to the end of your lance. These work by stopping splashes because the jets of water are contained within the housing of the head.
Work in gentle sweeps across the paving. Pay attention as you go that each area of paving is cleaned evenly. You don't want to be left with 'tiger stripes' when you're paving has dried. This is often the case if you use a low powered jet washer. Or if a cleaning liquid has not been applied to heavily soiled and dirty paving beforehand.
If you're paving was very dirty you will have a lot of dirt that needs to be cleaned up afterwards. Often you can rinse the dirt into a drain or grassed or soiled area. But remember that if you are pressure washing your paving towards a public highway, you will need to make sure the pavement and road are also washed or swept afterwards to remove the dirt.
Once the block paving is clean you need to allow to dry. Once dry re-sand any areas that will have lost jointing sand between the paving blocks when they were cleaned. This is essential to maintain the structural strength of the block paving.
Once finished, re point with cement any areas of pointing that may have come loose.
Now your block paving is clean, keep it clean for longer by applying an apply & leave cleaner.
That's it, you're done! You're now an expert in pressure washing block paving.

Other things to consider when using a pressure washer to clean your block paving

Try to avoid deep-down joint sand loss?

Loss of deep-down joint sand in block paving allows water to penetrate the sand below leading to your paving sinking The jointing sand gives the paving bricks their locking together strength. The sand will be lost by being 'blown out' by the strength of the jet of water if used to clean your paving at close range. This is often the case when using a pressure washer to remove weeds and moss.

"But I will replace the joint sand later" I hear you say. Well if you remember when you're paving was laid, the contractor would have used a whacker plate compactor. He used this to not only compact the paving but to also force the kiln dried sand into the joints of the paving. This action locks the individual brick pavers together. You can replace this dry sand yes, but you don't compact your paving again after each clean to lock the block paving together again.

Eventually the individual bricks will become loose because the sand replaced is weak and light because of non compaction of the paving around it. This leaves your paving prone to sinking because of a loss of the sand that gives strength to the structure of the paving. Especially if not replaced in the joints between the bricks. It also allows rain water to penetrate the paving joints easier which in turn leads to the sub base becoming soft.

Try not to over-use your pressure washer to clean your block paving

If possible, try not to become addicted to cleaning your block paving with a pressure washer. Try using a paving cleaner or weed killer first to kill weeds and remove ingrained dirt. Pressure washing block paving should be used to gently clean and rinse the surface. It should not used to blast the paving clean at maximum power & force.

Use the pressure washer lance at an angle

When pressure washing block paving try to hold the lance at 45 degrees The lance of the pressure washer should be held at an angle so not to be removing more than the top 1-2 centimeter of the jointing sand. Remove as little sand as possible between the pavers when the cleaning takes place.

Hold the lance at a distance of around 200mm (8 inch) from the block paving surface. If possible when pressure washing block paving use the lance at an angle of 45 degrees to the paving surface.

When you are pressure washing block paving never aim the jet of water directly at or into the paving joints from overhead. This can do severe damage to the underlying grit sand base the block paving is laid upon.

Frequently asked questions about pressure washing block paving.

When is the best time to clean block paving with a pressure washer?

Pressure washing block paving can be done at any time of year. But our recommended times of year would be autumn and spring for pressure washing block paving. This is because its always good to have clean pavers before winter sets in to avoid slippy paving and spring cleaning is great before things begin to grow. After cleaning with a pressure washer consider applying an apply and leave cleaner. These help keep your block paving weed, algae and moss free for longer. Which cuts down on the need to use a pressure washer to clean your block paving.

Can you clean block paving with a sealer applied to the surface?

Yes. If your block paving has been sealed with a sealant you should be perfectly fine to clean block paving with a jet washer. If a sealer has been applied by sprayer or roller & tray, you should only have to wash the paving using the jet washer to rinse the paving rather than to blast the surface. Always check with the sealer manufacturer if you are unsure. You may need to re-apply any paving sealer after pressure washing block paving. Especially if an acrylic sealer has been used to seal the paving.

Will pressure washing block paving cause white staining on the surface?

The white blooming or staining on the surface of block paving is caused by salts being released by the paving. This is often referred to as efflorescence. If your paving is newly laid, cleaning with a pressure washer could release salts from within the pavers so this could be possible. Salts will often be released way before its time to clean new block paving with a power washer. If your paving is old or has been laid for some considerable time then cleaning with a pressure washer will not cause white staining or efflorescence to develop.

Do you want to buy a new pressure washer to clean your block paving? Do you want more information to help you decide the best pressure washer you can buy to clean your paving. Read our pressure washer reviews.