Clean your patio without a pressure washer: This two-product trick keeps paving slabs looking like new.

Many people instinctively reach for a pressure washer or harsh, trade-style chemicals from the DIY shop. A British DIYer shows there is a far simpler, quieter approach that is kinder to the environment, pets and the stone surface: two everyday cupboard staples, a bit of time and a stiff scrubbing brush.

Why the patio looks so bad after winter

After months of rain, frost and weak sunshine, patio slabs tend to pick up a stubborn mix of algae, moss, lichen and everyday road grime. If you leave metal furniture outdoors, you may also get ugly rust rings around chair and table legs. Pale stones can quickly end up looking patchy and “tired”.

The usual response is predictable: drag out the pressure washer, add some strong cleaner, and “blast everything off”. Over time, that approach often creates fresh problems:

• The jet from a pressure washer can wash jointing material out and roughen the surface.
• Aggressive cleaners can attack pointing and some types of natural stone.
• Dirt may come off initially, but a roughened surface tends to hold onto grime more quickly afterwards.

Many people now swear by household options such as vinegar-based cleaner. It can help with limescale and some deposits, but it is still an acid. On sensitive stones it may leave faint etching marks you only notice later when the light hits at an angle. Soil organisms around the patio also tend not to enjoy repeated acidic exposure.

"If you use high pressure and aggressive products every year, you’ll eventually clean your patio to pieces."

The straightforward two-product trick for clean slabs (Fix it with Fowlers)

The British DIY channel “Fix it with Fowlers” demonstrates an alternative that sounds almost too plain: a bag of soda crystals, a squirt of washing-up liquid, plus a scrubbing brush and a little patience. For many typical patios, that really is enough.

What soda crystals actually are

Soda crystals (also sold as washing soda) are an old-school household helper from before specialist cleaners were everywhere. They are an alkaline salt that breaks down grease and helps loosen organic dirt. Important: this is not the same as bicarbonate of soda (the baking ingredient), and it is certainly not the same as caustic drain cleaners based on sodium hydroxide.

Used correctly, soda crystals can:

• cut through greasy films and barbecue residue
• soften algae layers and general grime
• feel noticeably less aggressive than many “patio-specific” products

Alongside that, you use ordinary washing-up liquid. In the kitchen it helps split grease and oil so it rinses away easily; on patios it is particularly helpful for barbecue fat, soot and traffic-film style deposits.

Step-by-step: how the method works

Preparation matters nearly as much as the cleaner. If you simply pour products on and hope for the best, you are more likely to end up with streaks.

1. Clear the joints: Use a joint scraper or small trowel to remove weeds and loose soil.
2. Sweep thoroughly: Use a stiff broom to shift dust, sand and larger debris.
3. Dampen the slabs: Wet the area evenly with a garden hose or watering can.
4. Sprinkle soda crystals: Spread a thin layer over the wet surface-there is no need for thick piles.
5. Add washing-up liquid: Apply several thin lines or a few squirts across the slabs.
6. Scrub firmly: Work it in with a stiff scrubbing brush, including along the joints.

Next comes the slightly counter-intuitive bit: don’t rinse straight away-let it sit. The DIYer leaves the mixture on the slabs for up to 48 hours, then rinses again with clean water. During that time, part of the growth and staining loosens on its own.

"If you give the cleaner time, you’ll save effort later-the patio comes up cleaner, without the roaring machine."

Safety and common mistakes when cleaning a patio

Soda crystals are often considered relatively gentle for household use, but they are clearly alkaline. In other words, you do not need to spread half a kilogram at once. For many domestic patios, a light dusting-or a bucket of hot water with a few tablespoons-can be perfectly adequate.

What homeowners should keep in mind

• Avoid contact with eyes and skin: Short rubber gloves are a sensible choice.
• Keep children and animals away: While the surface is wet, it is best that nobody walks across it.
• Do a test patch: If you have sensitive natural stone, try it first in an inconspicuous spot.
• Rinse thoroughly: After the dwell time, use plenty of water so no residue is left behind.

A frequent mistake is mixing multiple products-vinegar here, a chlorine cleaner there, perhaps a stone cleaner on top. Random combinations can harm not only the stone, but also your lungs if gases are produced. Stick to one method per pass and keep the area well ventilated.

When a pressure washer still makes sense

Heavily clogged joints, baked-on mud, or decades-old buildup can sometimes be very hard to shift by hand alone. A pressure washer can help-but use it carefully:

• use a wide fan spray rather than a pinpoint jet
• increase the distance to the surface; don’t work right up close
• clean joints only at an angle and with reduced force
• renew jointing material afterwards if a lot has been washed out

If you pre-treat first with soda crystals and washing-up liquid, you often need much less pressure at the end because the dirt has already been loosened.

How to keep the patio clean for longer

Even the best cleaner is limited if everything turns green again a few weeks later. A simple routine keeps the workload down.

Measure	Frequency	Benefit
Sweep with a stiff broom	every 1–2 weeks	removes leaves and dust, reducing food for algae
Light wash with warm water and washing-up liquid	as needed, roughly monthly	lifts grease films and fresh marks early
Two-product deep clean with soda crystals	1–2 times per year	thorough clean before algae beds in deeply
Move garden furniture	a few times per season	prevents permanent shade patches and rust zones

If you plan a lighter soda-crystals-and-washing-up-liquid session in autumn, spring starts much more easily. The usual black and green veils are often far less noticeable.

Which stones suit it-and where to be cautious

This approach is mainly aimed at common concrete slabs and many ceramic finishes. With natural stone, it is worth taking a closer look:

• Concrete slabs: Usually straightforward, as long as the joints are not already crumbling.
• Ceramic patio tiles: Typically unproblematic, but keep an eye on the joints.
• Sandstone, limestone, marble: Test a small area first and consider a softer brush.
• Clay pavers: Often robust, but watch for efflorescence and colour changes.

Alkaline products such as soda crystals can, depending on concentration, roughen or discolour certain natural stones. In that case, the safer option is a diluted bucket solution with a shorter dwell time, rather than sprinkling dry crystals and leaving them for two days.

More than looks: environment, pets and the household budget

Getting the patio looking “like new” is only part of it. Avoiding harsh cleaners also helps protect what grows and lives around the slabs. A soda-crystals-and-washing-up-liquid mix generally breaks down far more readily than specialist concrete chemicals that can end up in drains or flowerbeds.

For pet owners, this matters too. Dogs and cats may cross the wet area and later lick their paws. A combination that avoids strong acids and chlorine-and, after thorough rinsing, does not leave residues in puddles-reduces the risk significantly.

Cost is the final piece of the puzzle. Soda crystals are only a few pounds per pack in supermarkets and chemists, and most households already have washing-up liquid under the sink. Compared with specialist cleaners-or buying a new pressure washer-this is easier on the budget, and on neighbours’ nerves when sunny weekends are no longer filled with hours of engine noise.