June 21, 2017 4 Comments
Several customers asked us for our suggestions as to the best way to remove lichen (including "black spot" which is black lichen) by softwashing.
Lichen are white, brown, yellow and black (i.e. "black spot") growths that grow on slate and concrete tiled roofs, as well as on concrete paths, monoblock drives, brickwork and occasionally on wall render.
Lichen can be very tough to remove and pressure washing alone is rarely effective.
The best way we've found to remove lichen is to first kill it by treating with Benz Tornado Cleanze, applied neat.
Quick tip: Tornado Cleanze contains a particularly potent surfactant that can foam up when rinsing. To reduce foaming use low-pressure and minimise agitation when rinsing.
Or, treat with Benz Lightning Cleanze (dilute according to the severity of infestation and the results of your test patch).
Follow this treatment with a light pressure/jet wash, working the dead lichen spots with the jet to free them from the surface.
If some infestation remains, repeat the treatment.
Finally, treat with Benz Bio Cleanze. This will continue to deep clean over several months, killing any remaining spores, while also providing residual protection against recolonisation.
Important safety tip: If children or animals will walk on the treated surface, apply Bio Cleanze at only 50:1, keeping them well away from the working area and allow the surface to become completely dry before allowing them back.
Important note re pressure washing: Using a pressure/power/jet washer on lichen without first killing it with Lightning Cleanze or Tornado Cleanze – which means the growths will still be well rooted into the surface – may damage the surface because the pressure will rip the still living roots out. Whereas after treatment the roots will be dead and will to some extent have released their grip.
We've found that when first killed with Lightning Cleanze or Tornado Cleanze jet washing will lift the roots out much more easily.
Important note re wall render: When treating render we generally do not recommend high-pressure jet washing, as it can damage the delicate surface of modern renders such as KRend and Weber.
Use of a jet washer, set to low pressure and/or using a wide angle fan jet, is fine for rinsing however. The pressure of the water when it contacts the render should be approximately that of tap water pressure.
The combination of Lightning Cleanze or Tornado Cleanze followed by a light pressure wash will remove the majority of lichen.
Bio Cleanze will then work through time – from 6 weeks to 12 months – to remove any remaining lichen and kill any remaining spores deep into the surface.
The actual time it takes Bio Cleanze to work will depend on factors such as:
1) Brush and hose down, or lightly pressure wash, the surface to remove loose organic matter.
2) Treat with neat Tornado Cleanze, or Lightning Cleanze at 4-5:1 dilution, brushing the chemical into the lichen to help penetration (multiple treatments can be beneficial for badly infested surfaces).
3) Rinse and observe the results.
4) If necessary apply repeat treatments of Lightning Cleanze or Tornado Cleanze.
5) Lightly pressure wash any remaining black lichen, which will now be dead and its roots will more easily lift from the surface. (even a domestic pressure washer will do the job after a softwash treatment, as we have proved).
6) Apply Bio Cleanze at 50:1. This will find its way deep into the surface, clean out any remaining lichen spores, and provide long-term residual biocide protection against re-colonisation.
7) When the first signs of algae or lichen growth return, or as a regular 6-18 month regular re-treatment, it is usually sufficient to apply Bio Cleanze at 50:1 (40:1 in cold weather) alone as part of your ongoing maintenance plan.
Quick tip: Offering your customers a "Clean & Maintain" ongoing maintenance plan will give them a perpetually clean property and will give you a continual stream of lucrative repeat softwash business.
Lichen usually takes a long time, even years, to return but sometimes, in damp, shaded areas of paths and patios, algae will be noticed sometime during the 6-18 months following treatment with Benz Softwash biocides.
At this point a quick "spray & go" with Bio Cleanze is all that is required to keep the surfaces immaculately clean and your customer very happy.
Benz soft washing how-to videos cover every aspect of soft washing. We show you how to soft wash domestic and commercial roofs, paths and drives, tarmac, concrete, walls, wall render (including KRend, Monocouche, Weber), wet pour safety surfaces, tennis courts, car parks, wood decking, fences, sheds and more ...
Our sincere wishes for a good life and a profitable business,
Ben, Leo & Fiona
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September 15, 2021
Many soft wash contractors can be unsure of the safest way to soft wash asbestos roofs. So in this post we lay out the best practices we've learned from running a soft washing business since 2013.
Click the link on this page to learn how to treat asbestos ...
September 08, 2021
Ben demonstrates how to scrape moss and lichen from natural slate roof tiles and treat the biofilm to kill all the growths on this natural slate roof.
Click the link on this page to watch the how-to video ...
September 02, 2021 2 Comments
When soft washing it's vitally important to protect surrounding building materials. e.g. lead flashing. And not to create "clean streaks" – from overspray and run-off – on surfaces that are not part of your contract.
Click the link on this page to watch how we achieve this when soft washing a chimney ...
It's a free resource for people wanting to learn about the soft washing industry, to expand an existing business, or build a new business.
Soft washing reduces, or even eliminates, the need to use high-pressure washing.
Instead, once the build up of algae, lichen, fungus, moss and mould – the root causes of properties looking "dirty" – has been treated, the natural "self-cleansing" of sun, rain and wind removes the surface residue through time.
By educating the cleaning trade and public about soft washing we are helping develop an industry that offers sustainable treatments to clean and maintain exterior hard surfaces.
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