How To Clean Concrete and Sandstone with Bio-Shield®

How To Clean Concrete and Sandstone with Bio-Shield®

Including cleaning of:

  • Smooth or Exposed Aggregate Concrete.
  • Concrete Paths, Paving and Cobblestones
  • Sandstone Pavers and Patios

Black and discoloured concrete and sandstone is not only unsightly, it is dangerous, being a major reason for falls at home. What looks like dirt is actually a black algae that is very easy to kill and remove with Bio-Shield®.

An easy spray on application of Bio-Shield® will clean concrete and sandstone - Without Pressure Cleaning or Scrubbing, and will keep it clean for extended periods, up to 4 years in some situations.

Bio-Shield® vs Pressure Cleaning - Which one is better?

Pressure cleaning to remove black algae and moss will create damage by stripping away the cement and sand surface layer, leaving a rougher, more porous surface that will trap dirt and promote excessive black algae and moss regrowth.
Pressure cleaning is a time consuming, messy, expensive, and ultimately futile way to clean these surfaces: if they are not sterilised in conjunction with pressure cleaning, the spores within the concrete and sandstone will quickly regrow and discolour the surface again.

The easiest and most cost effective method for cleaning and maintaining concrete and sandstone are the application of exterior cleaning solutions like Bio-Shield.

Application of Bio-Shield takes a fraction of the time that pressure cleaning will.
Then just sit back and watch the concrete and sandstone self-clean over the next 1 to 3 months, and stay clean for up to 4 years.

Only Bio-Shield will keep the treated surface clean for longer.
Regular lighter applications of Bio-Shield at the first sign of re-growths will effect a rapid clean up and keep the surface clean again for an extended period.

How To Clean Concrete and Sandstone - Bio-Shield® Application Instructions

Spread Rates
Spread rate for diluted Bio-Shield on concrete and sandstone should be a minimum of 3m2 per diluted litre to ensure saturation.

Jet-Stream® 2.5L Applicator will cover 150m2
Bio-Shield® 5L Concentrate will cover 300m2
 Jet-Stream® 7.5L Applicator pack will cover 470m2.

Spread rate for maintenance treatments on clean concrete and sandstone can be up to 5m2 per diluted litre.

Following these simple steps will ensure a job the professionals would envy and long lasting protection against algae and moss regrowth.

  • Remove loose debris, tree leaves, dirt etc, from the surface.
  • The concrete or sandstone surface can be either dry or damp.
  • Moss can be damp but not saturated with water.
  • Jet-Stream Applicator - Connect to garden hose and turn on hose tap to 1/3 to ¼ open.
  • Move rotary switch on the side of the applicator around to the ON position to begin spraying in broad, even strokes to SATURATE the surface.
  • Bio-Shield 5L - Pre-dilute the Bio-Shield concentrate at 1:20 = 50ml BS to 1000ml clean water and apply with a pump up garden sprayer in slow even strokes to SATURATE the surface.

Ensure moss in shaded areas, cracks and joints, is saturated to the base of the growths.
The treated surface will temporarily change to an orange brown colour as the Bio-Shield reacts with the algae. This colour change will fade over 24 to 48 hours.
Thick moss must be allowed to dry out after application and will change colour to brown over a few days, indicating it is dead.

Bio-Shield does not kill plants, grass or trees, but may cause minor leaf damage (spots) on delicate plants. Hose off any affected plants after the application to prevent any damage.

Any rain showers on the treated surface after 1 to 2 hours are OK and will not stop the Bio-Shield from killing the black algae.

Why choose Bio-Shield® for your DIY Concrete and Sandstone Cleaning?
Bio-Shield has been developed as an outdoor cleaner through 35 years of use in a demanding commercial environment so it works extremely well.
Bio-Shield is a high quality outdoor cleaner that cleans without pressure washing or scrubbing, and contains no bleach, acids or phosphates
The higher concentration of active ingredients in Bio-Shield when compared to other outdoor cleaners such as Wet and Forget, means Bio-Shield costs less per diluted litre and covers more area at a lower cost.

Bio-Shield Mixing Ratios

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