Pressure washing
Permitted and fenced. A manufacturer's own guidance gives the angle, the setting and the check afterwards — and says excess shortens the life of the surface.
Precautions
- Wear eye protection
- Test on an inconspicuous area first
- Check the manufacturer's instructions
- Keep away from children and pets
In detail
Pressure washing cleans a hard outdoor surface with kinetic energy alone, and a paving manufacturer's guidance is the most useful document this catalogue holds on it because it permits the method and then bounds it precisely. Used to excess it damages the paving and shortens its service life. The instructions are specific: sweep first; use a low-pressure setting; do NOT direct the lance down onto the paving, because that costs jointing material; hold it at a shallow angle not greater than thirty degrees across the diagonal rather than parallel to the joints; test first, because some machines mark wet cast paving; and inspect afterwards to ensure the joints are full, since empty joints are detrimental to the pavement's performance. That last step is the one nobody does, and it is why a jet-washed patio grows weeds and moves the following season. Two hazards travel with the method and neither is about the surface. Water under pressure goes where poured water does not — behind cladding, into airbricks and past seals. And the spray aerosolises whatever it hits, which matters when the surface carries algae, moss or bird droppings.
What works
Pressure washing is effective against Moss and lichen Supported
Why
- Pressure washing is explained by Mechanical action and abrasion
Aftercare and prevention
- Pressure washing requires the aftercare Concrete and stone paving
Sources for this page
Sources
Cleaning & Maintenance Guidelines — Gardens & Driveways
Marshalls plc · Manufacturer documentation
Relied on for: That power washing used to excess damages paving and shortens its service life, that the lance must not be directed down onto the paving, that it should be held at a shallow angle not greater than 30 degrees across the diagonal, that some machines mark wet cast paving so a test is needed, and that joints must be inspected afterwards. (states this directly)
Verification: a person has read the passage relied on.
Read on — General Advice, Power Washing, Acid Washing, Seasonal Maintenance, Sealants, the per-stain sections and Organic Growth. Supports the claim as stated.
Last reviewed by a person on .