Your £5k Block Paving is Falling Apart
Pressure washing blasts out jointing sand. Wire brushing scratches surfaces. Bleach discolours coloured blocks. Our professional formula kills moss in joints and on surfaces in 24-48 hours – preserving jointing sand and protecting your investment.
Why Block Paving Gets Moss Worse Than Anything Else
Block paving is moss heaven. Those neat joints between blocks? Perfect anchor points for moss roots. The textured surface? Holds moisture beautifully. The sand-filled gaps? Provides nutrients and stability for moss to establish deep growth.
The real danger: Moss on block paving isn’t just surface growth. It roots deep into the sand-filled joints, slowly pushing blocks apart and creating an uneven, unsafe surface. Left unchecked, it can cause structural damage that requires complete re-laying.
How to Remove Moss from Block Paving Without Destroying It
Step 1: Clear and Inspect (15 minutes)
Move vehicles and sweep the entire area with a stiff broom to remove loose debris. While sweeping, check for loose or damaged blocks – these need gentle treatment as aggressive cleaning can worsen the problem.
Critical check: Look at your joints. If sand levels are already low, avoid pressure washing entirely as you’ll make it worse.
Step 2: Apply Moss Treatment
Professional moss killer (safest for block paving): Spray a block-paving-safe treatment over the entire surface, ensuring it penetrates the joints. Let it work for 24-48 hours. The moss will die without you having to blast out precious jointing sand.
DIY alternatives (use with caution):
- Baking soda: Sprinkle between joints and on surface. Leave for 24 hours, then brush away gently. Won’t damage blocks but needs multiple applications.
- Vinegar solution: 50/50 water and white vinegar. Spray on, wait 2-3 hours, rinse gently. Can darken some block colours – test first.
- Diluted bleach: 1 part bleach to 5 parts water. Kills moss but WILL permanently discolour coloured blocks. Use only on plain grey blocks and test first.
What to NEVER do: Don’t pressure wash before treating the moss. You’ll blast spores deep into every joint and lose jointing sand in the process.
Step 3: Remove Dead Moss (Carefully)
After 48 hours, the moss should be dead (brown/black). Use a stiff brush to sweep it away. For stubborn areas:
- Manual brushing: Safest option. Takes longer but preserves jointing sand.
- Pressure washing (only if necessary): Use LOWEST setting, keep nozzle 30cm+ away, angle at 45 degrees to blocks (NEVER aim directly into joints), work quickly without dwelling on one spot.
Expect to lose some sand: If you pressure wash, plan to re-sand joints afterward. This is why chemical treatment alone is better.
Step 4: Re-Sand Joints (If Needed)
If joints look empty after cleaning, you must re-sand them or blocks will shift:
- Use kiln-dried jointing sand (never builders sand)
- Brush sand into joints, working in multiple directions
- Compact with a vibrating plate compactor if available
- Brush in more sand to top up
- Spray lightly with water to help sand settle
Preventing Moss from Coming Back
Block paving needs more prevention than other surfaces because moss roots so deeply in the joints. Our complete moss removal guide covers prevention strategies for all paved surfaces.
Seal Your Block Paving
A quality sealant creates a barrier that makes it much harder for moss to establish. Apply every 2-3 years after cleaning. Choose a breathable sealant that won’t trap moisture underneath.
Keep Joints Properly Filled
Empty joints invite moss. Check annually and top up with kiln-dried sand where needed. Full joints = no space for moss roots.
Improve Drainage
Standing water accelerates moss growth. Ensure your block paving still has proper fall (slight slope) for water runoff. If water pools, you may need professional relevelling.
Reduce Shade
Trim overhanging trees and shrubs. Even partial shade makes a massive difference to moss growth rates.
Regular Light Maintenance
Sweep weekly to remove leaves and organic matter. This 5-minute habit stops moss before it starts, similar to maintaining driveways and other paved areas.
Block Paving Materials: Specific Considerations
Concrete blocks: Most common type. Relatively durable but porous, making them prone to moss. Can handle gentle treatments. Watch for colour fade with bleach.
Clay pavers: More expensive, denser, less porous. Moss still grows but usually on surface rather than deep in material. Can use stronger treatments.
Natural stone sets: Most vulnerable to staining. Avoid bleach entirely. Use gentle, pH-neutral treatments only.
Permeable blocks: Designed for drainage but the gaps make them moss magnets. Treatment needs to penetrate deep channels.
Common Block Paving Mistakes
Over-pressure washing: This is THE number one way people destroy their block paving. Every blast removes sand. After a few years of aggressive pressure washing, your blocks will be loose and uneven.
Using the wrong sand: Builders sand or play sand won’t work. You need kiln-dried jointing sand or polymeric sand that resists washout.
Ignoring loose blocks: If blocks are already moving, aggressive cleaning will make it worse. Fix structural issues before cleaning.
Not re-sanding after cleaning: Empty joints mean loose blocks within months. Always top up after any cleaning that removes sand.
Quick Troubleshooting
Q: My blocks are already loose. Can I still clean them?
A: Fix the structural issue first. Add sand to joints, compact, then treat moss gently with chemicals only – no pressure washing.
Q: How often should I clean block paving?
A: Deep clean once yearly. Treat moss immediately when you spot it (2-3 times yearly in shady areas). Weekly sweeping prevents major problems.
Q: Can I just keep pressure washing the moss?
A: You can, but in 2-3 years your blocks will be loose, uneven, and need professional re-laying at £50-70 per square metre. Chemical treatment preserves the structure.
Q: Is moss between blocks a sign of poor installation?
A: Not necessarily. Even perfectly installed block paving gets moss in the right conditions (shade + moisture). It’s about maintenance, not installation quality.
When to Call Professionals
DIY block paving moss removal works if the moss is light and the paving is in good condition. Get professional help if:
- Blocks are loose or uneven (needs re-laying first)
- You’ve lost significant jointing sand
- The area is large (50m²+)
- You have expensive clay pavers or natural stone
- Previous DIY attempts have caused damage
- You want sealant applied (requires proper surface prep)
Professional block paving restoration includes moss treatment, careful cleaning, re-sanding, compaction, and sealing – preserving your investment rather than damaging it.
Related Surfaces
If your block paving has moss, check adjacent paths and fencing too. Moss spores spread easily between neighbouring surfaces, so treating everything at once prevents recontamination.
The Bottom Line
Block paving requires gentler moss treatment than solid concrete surfaces. The key is killing moss chemically rather than blasting it away physically. Preserve your jointing sand and you preserve your driveway.
For light moss on structurally sound paving, careful DIY treatment works. For extensive moss or when blocks are already compromised, professional treatment protects your expensive investment.
Ready to protect your block paving? Safe for all block types, preserves jointing sand, kills moss in 24-48 hours.
