A driveway can look tired long before the paving itself has reached the end of its life. Green moss, black spotting, weeds and traffic marks quickly take the edge off a well-kept property. Knowing how to clean block paving properly can bring back its original colour and improve kerb appeal without the cost of replacing a perfectly sound surface.
The key is not simply to use the strongest pressure washer setting available. Block paving is made up of individual units held in place by compacted bedding and jointing sand. Clean it too aggressively and you can strip the sand from between the blocks, disturb the surface and leave it more vulnerable to movement and weed growth. A careful clean gives a far better, longer-lasting result.
Check the paving before you start
Start by looking closely at the condition of the driveway, path or patio. A few loose blocks, sunken areas or crumbling edges should be dealt with before any deep clean. Water pressure can make an existing problem worse, especially where the sub-base beneath the paving has started to move.
Pay attention to the type of staining as well. Moss and algae need a different approach from oil, rust or tyre marks. Black spots are often lichen, which can remain visible even after the surface has been washed and may need a suitable treatment to break it down over time.
Choose a dry day if possible. You will see the dirt more clearly, be able to sweep effectively and have a better chance of allowing fresh jointing sand to settle afterwards. Avoid cleaning in freezing weather, or during heavy rain when runoff is harder to control.
How to clean block paving step by step
Clear the surface and remove weeds
Move cars, pots, furniture and loose items off the area. Sweep away leaves, grit and soil with a stiff outdoor brush. This is not a wasted step: clearing loose debris means the cleaning treatment can reach the growth and staining beneath it.
Pull out larger weeds by hand, including as much of the root as you can. For persistent growth between the blocks, use an appropriate weed treatment first and allow it time to work according to the manufacturer’s instructions. Do not pressure wash healthy, established weeds into the joints and assume the job is finished. Fragments and roots left behind can return surprisingly quickly.
Treat moss, algae and black spots
Moss and algae thrive in shaded, damp parts of British gardens and driveways. A purpose-made exterior cleaner or biocide can kill the growth before washing, making it easier to remove and helping to slow its return. Apply it evenly and keep it off lawns, planted borders and nearby water features unless the product is specifically suitable for those areas.
Household bleach is often used as a shortcut, but it is not the best answer for every surface. It can harm surrounding planting, discolour some materials and create an unpleasant runoff issue. A cleaner designed for hard landscaping, used at the right dilution, is the more controlled option. Never mix cleaning products.
Lichen may need patience. It often leaves pale or dark marks that do not disappear the moment the visible growth has gone. With the correct treatment and normal weathering, the remaining marks usually improve rather than needing repeated, forceful washing.
Use a pressure washer with care
A pressure washer is effective, but technique matters more than raw power. Use a fan nozzle rather than a narrow, concentrated jet, and begin on a low setting in an inconspicuous area. Hold the lance at an angle, not straight down into the joints, and keep it moving across the paving.
Work methodically from one edge to the other, washing the blocks in the same direction rather than circling over one patch. Keep enough distance between the nozzle and the paving to clean the surface without cutting into it. If the sand is being blasted out rapidly, stop and reduce the pressure or move the lance further away.
Avoid directing water towards garage doors, air bricks, thresholds or the base of rendered walls. On a sloping driveway, think about where dirty water will travel before starting. It should not be allowed to carry sediment into surface-water drains, neighbouring ground or planted areas.
For lightly soiled paving, a stiff brush, warm water and an exterior-cleaning solution may be enough. Pressure washing is useful for a deeper restoration, but it is not automatically the right method for every old or delicate surface.
Deal with specific stains separately
Oil marks from vehicles are common on block-paved driveways. Absorb fresh spills quickly with an appropriate absorbent material, then use a paving degreaser made for oil contamination. Give it time to work before scrubbing and rinsing. Old oil stains can be stubborn because they have penetrated the porous surface, so improvement may be gradual rather than instant.
Rust staining from metal furniture, fertiliser or drainage can require a specialist rust remover that is safe for paving. Test any product in a discreet place first. Paint, cement splashes and tyre marks also need their own treatment, and harsh acids should be avoided unless you fully understand their suitability for the specific block type.
Trying to solve every stain with more pressure is a common mistake. It can leave a noticeably lighter patch, roughen the face of the block or remove material from the joints without properly lifting the stain.
Replace the jointing sand after cleaning
Once the paving is clean, it needs time to dry fully. This is particularly important before re-sanding. The sand between blocks is not just there to make the driveway look finished. It helps lock the paving together, reduces movement and limits gaps where weeds can take hold.
Use clean, dry kiln-dried jointing sand suitable for block paving. Brush it across the surface with a soft broom until the joints are properly filled. A few passes in different directions will help it settle into narrow gaps. Do not use ordinary building sand, which can retain moisture and does not perform in the same way.
Some sand will settle after the next spell of rain or after vehicles use the driveway, so check the joints again and top them up where needed. If blocks are rocking, joints remain empty or the surface has dips, re-sanding alone will not fix the underlying issue. That is the point to arrange a professional assessment.
Should you seal block paving?
Sealing can make sense for some driveways and patios, particularly where oil staining, fading or frequent weed growth is a concern. A suitable sealer may deepen the colour, make later cleaning easier and add a measure of surface protection. However, it is not essential for every paved area.
The surface must be completely clean and dry before sealing. Trapping moisture, dirt or remaining algae beneath a sealer can leave a patchy finish and make future corrective work more difficult. Some sealers can also alter the appearance or reduce slip resistance, so the product needs to suit the paving and the location.
For many homeowners, regular cleaning and correct re-sanding are sufficient. Sealing is best viewed as an optional protective finish, not a substitute for repairing poor drainage, loose blocks or an unstable base.
When professional cleaning is the better choice
A domestic pressure washer can refresh a manageable area, but large driveways, commercial forecourts and heavily soiled patios often need more than a quick wash. Deep staining, widespread black spot, drainage concerns and fragile edging all call for a more considered approach.
Professional exterior cleaning combines the right treatment, controlled pressure and proper restoration of the joints. At Washed Away, the aim is always to restore rather than replace where possible, leaving the area clean, tidy and ready to make the property look cared for again. This is particularly useful where a driveway has not been maintained for years or where the wrong cleaning method could create an expensive repair.
Keep on top of leaves, soil and early moss growth after the clean, especially through autumn and winter. A simple sweep every few weeks and prompt attention to spills will protect the result far better than waiting until the paving looks beyond saving.