Paver Re-Sanding: How to Tell If You Actually Need It

Joint sand is the part of a paver patio nobody thinks about until it is gone, and by then the patio is usually telling you about it in three or four different ways at once.

Here is how to read those signs yourself, what re-sanding actually does, and the part most contractors leave out: plenty of patios do not need it yet.

What the sand between the stones is for

A paver field is a few hundred loose pieces sitting on a compacted base. What makes it behave like one surface instead of a pile of individual stones is the sand packed into the joints. It transfers load sideways from one paver to the next, so weight put on one stone is shared across its neighbors.

The sand does a second job too. A full joint leaves nowhere for weed seed and moss spore to germinate. An empty joint is a narrow planter, and it fills with whatever blows into it.

Why it disappears in North Jersey

Three things take it out, and we get all three.

• Heavy summer downpours. Water moving across the surface carries sand toward the low end and out the edges. A single hard storm can move a surprising amount.
• Freeze and thaw. Water in the joint expands as it freezes and heaves the sand upward, where the next rain washes it away. Over a Jersey winter that cycle runs dozens of times.
• Cleaning. Every wash takes some out, and a wash done with too much pressure or the wrong tip takes out a lot. This is the one that is avoidable.

How to check your own joints

You do not need anybody to tell you whether the sand is gone. Go out and look.

• Depth. Push a screwdriver or a key into a joint. If it drops more than about an eighth of an inch below the paver surface, the joint is running low. If it drops half an inch or more, the sand is largely gone.
• Weeds and moss. Growth coming up between the stones is not a weed problem. It is a sand problem with weeds as the symptom, and spraying them treats the symptom.
• Movement. Step across the field and feel for a stone that rocks or dips under your weight. That means it has lost the lateral support of its neighbors.
• Ants. Fine mounds of soil pushed up between pavers mean insects are working in the joint, which they cannot do through packed sand.
• Edges. Look at the perimeter row and the low end of the patio. Loss shows there first.

The honest answer: not every patio needs it

If your joints are full to within a hair of the paver surface, there is nothing to fix. Adding sand to a full joint accomplishes nothing except making a mess on the stone faces, and I will tell you that standing on your patio rather than write it into a quote.

There are also cases where re-sanding is the wrong fix outright. If the field has settled into a dip, or a section has sunk near a downspout, the base underneath has moved. Sand does not repair a base. Filling the joints on a patio that is genuinely settling just hides the problem until next spring, and you are better off having that section lifted and re-laid.

Very narrow joints on tightly butted pavers sometimes will not accept polymeric sand at all. That is worth knowing before somebody sells you a bag of it.

What re-sanding involves when it is warranted

It is a specific process and the order matters. The old sand, soil, moss, and weed root come out of the joints first, and the field gets cleaned properly at a pressure that will not blow out what is left. Then the surface has to dry completely, which usually means a separate visit or at minimum a long wait, because polymeric sand activated on a damp paver hazes the stone and that haze is difficult to remove.

Once it is dry, the sand goes in dry, gets swept and vibrated down to full joint depth, and the faces of the pavers are cleared of residue before any water touches it. Then it gets a controlled misting to activate the binder, and it sets into a firm but slightly flexible joint that sheds water and resists growth. That is paver re-sanding done the way it holds up.

Done right it typically buys several years before the joints need attention again, and it is most often booked as a single visit with a cleaning, which is how most paver work in Montville and the surrounding towns gets scheduled.

If you want to know whether your patio needs sand or just needs cleaning, call or text Nick at 973-897-1757. I will check the joints with you and give you the honest answer either way.