Your DIY Moss Removal is Destroying Your Tarmac
Tarmac is more delicate than you think. Every time you blast it with a pressure washer, you’re stripping away the surface aggregate. Every bleach application is breaking down the bitumen. And that wire brush? You’re creating micro-cracks where even more moss will grow. You’re not cleaning your driveway – you’re shortening its lifespan.
Why DIY tarmac cleaning causes permanent damage:
- X Pressure washers strip away surface aggregate (exposing base layer)
- X Bleach degrades bitumen binder (causes cracking and crumbling)
- X Wire brushing creates surface scratches (moss anchors deeper)
- X Harsh chemicals accelerate weathering and fade colour
- X Your tarmac needs resurfacing years earlier than it should
Tarmac Contractors Know Better
Professional tarmac layers never use pressure washers or harsh chemicals on asphalt. They use gentle, penetrating treatments that kill moss without damaging the delicate surface. One application preserves your tarmac rather than destroying it.
Clean tarmac safely and effectively:
– Kills moss in 24-48 hours (no pressure washing)
– Safe for tarmac surfaces (won’t damage bitumen)
– Preserves surface aggregate and colour
– Prevents regrowth without surface damage
*Stop the damage. Extend your tarmac’s life.*
Want to try DIY methods first? Read the complete guide below…
Why Tarmac Gets Moss (And Why It’s So Damaging)
Tarmac surfaces create ideal moss conditions. The slightly porous texture holds moisture, the dark colour absorbs heat (creating damp conditions when it cools), and any small cracks or imperfections become perfect moss anchor points.
The real problem: Moss on tarmac isn’t just slippery and ugly. As moss roots grow, they work into the surface, slowly breaking down the bitumen binder that holds the aggregate together. This accelerates weathering and can reduce your tarmac’s lifespan by years.
How to Remove Moss from Tarmac Without Damaging It
Step 1: Clear the Surface (10 minutes)
Sweep the entire tarmac area with a soft-bristled broom to remove loose debris, leaves, and dirt. This allows your moss treatment to reach the actual moss rather than sitting on top of debris.
Important: Use a soft broom, not a wire brush. Wire bristles scratch tarmac, creating more surface imperfections where moss can establish.
Step 2: Apply Gentle Moss Treatment
Professional moss killer (safest for tarmac): Spray a tarmac-safe treatment over the entire mossy area. These products are specifically formulated to kill moss without degrading bitumen. Let it work for 24-48 hours.
DIY alternatives (use extreme caution):
- Diluted vinegar: 3 parts water to 1 part white vinegar. Spray on, wait 2 hours, rinse gently. Vinegar works but can darken tarmac if too concentrated.
- Baking soda: Sprinkle on damp moss, leave 24 hours, sweep away. Gentle but needs multiple applications.
- Washing powder: Non-bio powder sprinkled on moss. Sits for 24 hours then sweep. Mild but slow-acting.
What to NEVER use on tarmac:
- Undiluted bleach: Destroys bitumen binder, causes cracking
- Pressure washers: Strip away surface aggregate, cause permanent damage
- Wire brushes: Scratch surface, create moss anchor points
- Salt: Damages tarmac structure and surrounding plants
Step 3: Remove Dead Moss Gently (2-3 days later)
After the treatment has killed the moss (it’ll turn brown/black), use a soft-bristled broom to sweep it away. Be patient and gentle – aggressive scrubbing damages tarmac more than the moss ever did.
For stubborn patches, use a soft brush and repeat the treatment rather than resorting to aggressive methods.
Step 4: Rinse Carefully
Use a garden hose on gentle setting to rinse away treatment residue and moss particles. Never use a pressure washer – even on low settings, the concentrated stream damages tarmac surfaces.
Preventing Moss from Coming Back
Tarmac requires different prevention than harder surfaces like concrete. The softer surface means you need gentler long-term strategies.
Improve Drainage
Standing water is moss enemy number one. Check your tarmac has proper drainage slope. If water pools, you may need to improve the base layer or add drainage channels. Professional assessment might be needed for significant pooling issues.
Reduce Shade
Trim overhanging branches and hedges aggressively. Tarmac needs more sunlight than concrete to stay moss-free because its dark colour absorbs heat differently.
Regular Light Cleaning
Sweep weekly with a soft broom to remove organic matter before it decomposes. This simple habit prevents more moss than any chemical treatment.
Apply Sealant
A quality tarmac sealant applied every 2-3 years creates a barrier that makes moss establishment much harder. Choose products specifically designed for asphalt – concrete sealants won’t work properly.
Fix Cracks Promptly
Small cracks in tarmac become moss strongholds. Fill them as soon as they appear with cold pour crack filler. Prevention is infinitely easier than removal.
Understanding Tarmac Damage
Tarmac (asphalt) consists of aggregate stones bound together with bitumen. This bitumen is sensitive to:
- Strong chemicals: Bleach, petroleum products, harsh cleaners break down the binder
- High pressure water: Strips away the protective surface layer
- Abrasive cleaning: Removes aggregate and creates weak spots
- UV exposure: Fades and dries out bitumen (moss makes this worse by holding moisture against surface)
Once you’ve damaged tarmac, you can’t undo it. The only fix is complete resurfacing at £40-60 per square metre. That’s why gentle moss treatment is critical.
Common Tarmac Moss Mistakes
Pressure washing: This is THE most common mistake. People think they’re being thorough, but they’re actually destroying their tarmac. Every pass removes aggregate and weakens the surface.
Using concrete treatments: Products designed for concrete are too harsh for tarmac’s softer surface. Always check labels specify “safe for asphalt/tarmac.”
Over-application of chemicals: More isn’t better. Excessive chemicals soak into tarmac and break down the bitumen from within.
Ignoring the cause: If you have persistent moss, addressing drainage and shade is essential. You can clean forever, but it’ll keep returning unless you fix the root cause.
Quick Troubleshooting
Q: Can I ever pressure wash tarmac?
A: No. Even professional tarmac cleaners avoid pressure washers. The risk of damage is too high. Gentle chemical treatment and soft brushing is always safer.
Q: My tarmac is already damaged. Can I still clean the moss?
A: Yes, but be extra gentle. Use chemical treatment only – no brushing or rinsing until the moss is completely dead. Consider professional resurfacing if damage is extensive.
Q: How often should I treat tarmac for moss?
A: In shady, damp conditions, 2-3 times yearly. In sunny, well-drained areas, once yearly may suffice. Prevention is always easier than cure.
Q: Will moss treatment affect the colour of my tarmac?
A: Quality moss killers designed for tarmac shouldn’t affect colour. Bleach and strong acids will darken or discolour it. Always test on a small hidden area first.
When to Call Professionals
DIY tarmac moss removal works for light coverage. Consider professional help if:
- Moss covers more than 30% of the surface
- Your tarmac is old or showing signs of wear
- You have poor drainage causing persistent problems
- Previous DIY attempts have caused visible damage
- You’re preparing for property sale (professional cleaning adds value)
- The tarmac needs resealing after cleaning
Professional tarmac cleaning costs £2-4 per square metre but preserves the surface properly. Compare this to £40-60 per square metre for complete resurfacing if you damage it.
Related Driveway Surfaces
Different driveway materials require different approaches. Resin driveways need even more careful treatment than tarmac – the wrong chemicals can permanently damage the surface. Adjacent paths should be treated at the same time to prevent moss spreading back to your clean tarmac.
The Bottom Line
Tarmac is more delicate than most people realize. The gentle approach to moss removal – chemical treatment without aggressive physical cleaning – protects your investment and extends your driveway’s lifespan.
Think of it like this: would you scrub your car paintwork with a wire brush and pressure washer? Of course not. Treat your tarmac with the same care, similar to how you’d approach cleaning delicate patio materials.
For small areas with light moss, gentle DIY treatment works fine. For extensive coverage or valuable tarmac surfaces, professional treatment protects your investment properly.
Remember: aggressive cleaning might look productive in the moment, but you’re trading short-term satisfaction for long-term damage. Choose gentle methods and your tarmac will thank you.
