How to get moss off a patio or driveway (and keep it off)

Why paving goes green so fast here

Moss and algae need moisture and shade, and Irish paving gets both for most of the year. North-facing patios, paths beside the house and driveways under trees are always the worst. The joints between blocks hold water and grit, which is exactly where moss and weeds take root.

Cleaning it properly

The order matters:

• Clear the surface: move pots and furniture, and sweep or scrape off thick moss first
• Wash the surface: a rotary surface cleaner gives an even finish with less spray than a lance alone
• Clear the joints: weeds and moss have to come out of the gaps, not just off the top
• Re-sand block paving: washing lifts jointing sand, and without it blocks loosen and weeds come straight back
• Treat it: a moss and algae treatment, applied as the label directs, slows the regrowth considerably

Mistakes that make it worse

Too much pressure, too close, can etch concrete, strip the surface off older slabs and blow out joints. Skipping the re-sand leaves cobble-lock loose and full of gaps for weeds. And washing without treating means the green film is back within months on a shaded patio.

Keeping it clean longer

Brush the paving regularly so debris doesn't collect in the joints, cut back anything that shades it, and fix drainage where water pools. A treatment once or twice a year after the main clean is the single biggest difference to how long it stays clean.

Questions