Moss and Growth Between Pavers

Why it grows in the joints

Joint sand holds moisture, and shaded hardscape stays damp for long periods. Add organic debris breaking down into the joint and you have soil, moisture and shade, which is all moss and weeds require. North-facing and tree-shaded patios always go first.

What pressure does to joints

A pressure washer aimed into a paver joint blasts out the jointing sand that holds the whole installation in place. Once the sand is gone the pavers shift, the surface becomes uneven, and water penetrates to the base where it undermines the bedding. The patio looks clean and is structurally worse.

The right sequence

Growth is treated and removed, the surface is cleaned at appropriate pressure, and then joints are re-sanded if sand was lost. Skipping the re-sanding step is what turns a cleaning into a repair job a year later. Anyone quoting paver cleaning without mentioning joint sand is not thinking past the day.

Reducing recurrence

Improving drainage, cutting back overhanging growth to let sun reach the surface, and keeping organic debris off the hardscape all reduce the conditions. Polymeric jointing sand resists growth better than plain sand where re-sanding is being done anyway.