Patio Cleaning Guide: How to Clean Your Patio Like a Pro

Updated February 2026 • 9 min read

Your patio is an extension of your living space – but after a British winter, it probably doesn't look very inviting. Green algae, black marks, moss between the slabs, and years of ground-in dirt can make even a quality patio look neglected. Here's our complete guide to getting it sparkling again.

Understanding Your Patio Type

Different patio surfaces need different approaches. Before you start, identify what you're working with:

Concrete Slabs

Most common and forgiving. Can handle pressure washing well. Watch for crumbling edges on old slabs.

Natural Stone

Sandstone, limestone, slate, granite. Some are softer than others – sandstone needs lower pressure than granite.

Porcelain

Increasingly popular. Very hard and durable. Cleans easily but joints can be narrow.

Block Paving

Individual blocks with sand-filled joints. Needs re-sanding after cleaning.

Step-by-Step Patio Cleaning

Step 1: Clear the Patio

Remove everything from the patio area:

Garden furniture
Plant pots and ornaments
BBQs and outdoor equipment
Sweep away leaves and loose debris

Step 2: Treat Weeds

Deal with weeds before washing – otherwise you're just trimming them:

Pull out weeds manually, including roots where possible
Or apply weed killer 1-2 weeks before cleaning
Scrape out moss from joints with an old knife or specialist tool

Step 3: Pre-Treat (For Heavy Soiling)

For patios with heavy algae, moss, or black marks:

Apply a patio cleaner or algae killer
Leave to work according to product instructions (usually 15-30 mins)
This breaks down organic matter so pressure washing is more effective

Step 4: Pressure Washing

The main event – here's how to do it properly:

Pressure: 1500-2500 PSI for most patios (lower for soft stone)
Nozzle: Use 25° or 40° fan nozzle, or surface cleaner attachment
Distance: Keep 15-30cm from surface
Technique: Work in overlapping passes, same direction throughout
Joints: Clean along joints, not across them, to avoid damage

Step 5: Rinse and Inspect

After the initial clean:

Rinse the entire area to remove loosened dirt
Check for missed spots or stubborn stains
Go over problem areas again
Rinse any adjacent walls or surfaces that got splashed

Step 6: Re-Point if Needed

If your patio has mortar joints that have deteriorated:

Allow surface to dry
Rake out loose/damaged mortar
Re-point with appropriate mortar or jointing compound
This prevents weed growth and stabilises slabs

⚠️ Common Patio Cleaning Mistakes

Too much pressure on soft stone – Can erode the surface permanently
Blasting directly into joints – Damages mortar and destabilises slabs
Cleaning in random patterns – Creates visible streaking
Ignoring the cause – If shade/drainage issues aren't addressed, algae returns quickly

Specific Stain Removal

Black Spots (Lichen)

Those stubborn black dots are lichen – a combination of algae and fungus. They're tough to remove:

Pre-treat with specialist lichen remover
Leave to work for several hours or overnight
Pressure wash – may need multiple treatments
Old lichen may leave shadow marks even after removal

Rust Stains

Often from metal furniture or fertiliser:

Use oxalic acid-based rust remover
Apply, leave to work, scrub and rinse
May need professional treatment for severe staining

Oil and Grease

From BBQs or food spills:

Apply degreaser or washing up liquid
Scrub with stiff brush
Pressure wash
Old oil stains may need specialist treatment

Maintaining Your Clean Patio

Keep your patio looking good longer:

Sweep regularly – Remove leaves and debris that trap moisture
Deal with spills quickly – Don't let stains set in
Trim overhanging plants – More sunlight means less algae
Clear drainage – Standing water encourages green growth
Annual maintenance clean – Much easier than major restoration
Consider sealing – Protects against stains and slows regrowth

🌞 The Shade Problem

If your patio is heavily shaded, it will always be more prone to algae and moss – that's just biology. While you can't move the sun, trimming back overhanging trees and shrubs to let in more light makes a significant difference to how long your patio stays clean.

DIY vs Professional Patio Cleaning

DIY works well if:

Your patio is relatively small
Soiling is light to moderate
You have standard concrete slabs
You're comfortable using a pressure washer

Professional cleaning is better if:

Large area or multiple outdoor surfaces
Natural stone that needs careful handling
Heavy soiling, deep staining, or years of neglect
You want biocide treatment for long-lasting results
Joints need re-pointing or slabs are unstable

Want Your Patio Professionally Cleaned?

Hulkzilla cleans patios across Somerset using professional equipment and techniques. We'll have your outdoor space looking its best in time for summer.

Call 07725 542334 Get a Free Quote

Summary

Patio cleaning involves clearing the area, treating weeds, pre-treating heavy soiling, careful pressure washing, and addressing the joints. Different surfaces need different approaches – what works for concrete might damage soft sandstone. Regular maintenance keeps your patio looking good and reduces the need for intensive cleaning. For large patios, natural stone, or stubborn staining, professional cleaning delivers the best results.