Cleaning Concrete and Asphalt Paths and Driveways

How To Clean Concrete and Asphalt Paths and Driveways with Bio-Shield®

Including cleaning of:

  • Smooth or Exposed Aggregate Concrete
  • Concrete Paving and Cobblestones
  • Concrete Walls, Bridges and Infrastructure
  • Unpainted Concrete Plaster
  • Asphalt Driveways and Carparks
  • Airport Runways, Taxiways and Hardstands

Why choose Bio-Shield® for your Concrete and Asphalt Cleaning?

Bio-Shield® has been developed through 40  years of use in a demanding commercial environment so it works extremely well.
Bio-Shield® is a high quality product, and contains no bleach, acids, salts or phosphates so is safe to use on any exterior surface
The high concentration of active ingredients in Bio-Shield® when compared to other outdoor cleaners like Wet and Forget or 30 Seconds means it will cost less per diluted litre and cover more area at a lower cost. Bio-Shield will not only clean concrete and asphalt surfaces, it will keep them clean longer than pressure cleaning alone, with less damage, up to 97% less water use and at least half the cost.

Should I pressure clean or use Bio-Shield to clean Concrete or Asphalt?

Pressure cleaning concrete to remove algae, moss and lichen growths will damage the surface by stripping away the cement and sand surface layer, leaving a rougher and more porous surface. 
Pressure cleaning asphalt is even more destructive leaving visible gouges in the surface.
Pressure Cleaning is a time consuming, expensive, and ultimately futile way to clean these surfaces: if they are not sterilized in conjunction with water blasting, the spores within the concrete and asphalt will quickly regrow and discolor the surface again.

Bio-Shield is the  best method for effective cleaning and maintaining concrete and asphalt.

A simple application will kill and remove the growths and keep the surface clean for extended periods. 
Regular lighter applications of Bio-Shield at the first sign of re-growths will effect a rapid clean up and keep the surface clean for an extended period. Reapplication schedule will depend on the micro climate around the treated surface - frequently damp and shaded areas may need  at least 6 to 12 monthly applications, a drier, sunny and open area may only need 2 yearly applications.

DIY Application or use our Professional Application Service for your Concrete Cleaning.

If you don't want to do DIY application we offer a professional Bio-Shield Application Service for domestic, commercial and industrial concrete and asphalt.
Prices are competitive - substantially less than the cost of water blasting. The benefits of using Bio-Shield to clean concrete is lower initial cost to clean and a treated surface will stay clean for longer than water blasting alone. Please contact us for a quote to clean your concrete or asphalt or to get in touch with a regional Bio-Shield Applicator near you.

Bio-Shield Concrete Cleaning - Before
Exposed Aggregate Concrete Cleaned

Bio-Shield® Application Instructions


For a successful DIY job, preparation is the key. Following these simple steps will ensure an effective clean up and a professional looking job.
Remove loose debris, tree leaves, dirt etc, from the surface.
Remove pets toys and feeding bowls from the area to be treated. Keep children and pets off the treated surface until it dries. Do not feed pets on the treated surface until  the surface has been flushed by rain.

The concrete surface can be either dry or damp. Asphalt is better treated when dry to maximise absorption of the Bio-Shield by the moss growths.

Check the weather forecast, or rain radar - no rain for 2 to 4 hours but brief showers after application on concrete will assist the action of Bio-Shield®
Air temperature above 10 degrees C° will help to accelerate bio-cidal action.

Premix the Bio-Shield® 1 part to 20 parts water in a pressure sprayer
If using the Jet-Stream applicator follow the instructions on the back label of the applicator.

Bio-Shield Mixing Ratios - for a Pressure Sprayer

Clean WaterBio-Shield ConcentrateDiluted Bio-Shield
1 Litre50 ml1.05 Litres
10 Litres500 ml10.5 Litres
15 Litres750 ml15.75 Litres
20 Litres1 Litre21 Litres

DIY Application for your Concrete Cleaning.


If you have a respirator, now is the time to put it on, along with a pair of gloves and soft soled shoes and/or a pair of long pants. If you don't have a respirator, try to stay upwind during application. Evaporation of the solution on a warmer day will generate vapour that should be avoided where possible.

Application is best done on an overcast day at any time of the year, or early morning and late afternoon in summer if a warm sunny day is forecast. This slows evaporation and speeds the treatment process.

Dividing the area to be treated into sections makes application easier- on concrete use the expansion joints for sectioning.
Begin application a the highest point and apply in slow, even strokes.  Allow the following stroke to overlap the previous stroke by 50% to ensure even and complete coverage.

On any thick or large clumps of moss place the nozzle of the pump up sprayer directly into the moss and inject it into the clump to ensure penetration to the deep roots and achieve a good kill.
If any moss does not brown off and stay brown the application has not saturated the entire growths. Reapply Bio-Shield to these growths

To ensure the treated surface stays wet for 10 to 15 minutes

Concrete will usually change to an orange-brown color - this is normal and the discoloration will fade over 24 to 48 hours.
Flush down any plants affected by overspray, using clean water.

Clean Up

Bio-Shield acts to kill the moss, algae on concrete over the next 2 to 3 hours. On Asphalt, Bio-Shield will give an effective kill in 2 to 4 hours.

After a few days there will be visible color changes to the dead moss and lichen growths. Black algae does not change color. On concrete there will be visible signs of the clean up starting after a few weeks as the concrete begins to lighten up.

Full clean up on concrete can take from 3 to 6 months and 3 to 12 months on Asphalt, depending on the condition of the concrete and the level of growths present.


It is best to reapply Bio-Shield® at the first signs of moss or green algae re-growth. 

On concrete and asphalt in ground contact, this would mean reapplication of Bio-Shield every 12 months to keep the surface clean.
If the area is shaded, has frequent rainfall or remains damp over winter then 6 monthly applications may be required. On open and sunny areas the  application schedule can be up to 2 years.

Maintenance application will be easier, faster and use less diluted solution; any new growths will die off and the surface will clean up quickly, sometimes within days.
Once the surface is clean, Bio-Shield® will give optimal results with regular treatments.