TL;DR
Resanding fixes structural problems and sealing fixes appearance problems, so they are not alternatives. Empty joints let pavers rock, shift, and grow weeds, and no sealer will restore a joint that has washed out. Sand goes in first, always. Sealing is optional on top of that, and it mostly buys stain resistance and color depth for two to five years.
What each job actually does
Joint sand is structural. A paver field works because each unit is locked against its neighbors by the sand between them. That interlock is what turns loose blocks into a surface that carries weight. When the joints empty out, individual pavers start to move, edges chip against each other, and the field slowly loses its shape.
A sealer is a coating. It sits on the paver surface, and depending on the product it either soaks into the pore structure or forms a film on top. What it does is slow the absorption of stains, deepen color, and in some formulations stabilize the top layer of joint sand.
The confusion comes from that last point. Some sealers do bind the surface of the sand, which is why people assume sealing solves joint loss. It does not. A sealer can hold sand that is already there; it cannot replace sand that is gone.
How do I know which problem I have?
Look into the joints. If you can see more than a quarter inch of open gap below the paver surface, or the sand moves when you drag a screwdriver through it, that is a sanding problem. If the joints are full but the surface shows dark oil marks, rust, or general dinginess, that is a sealing and cleaning problem.
Both can be true at once. In that case the sequence is fixed: clean, resand, then seal.
Why joint sand disappears in the first place
Water is the usual culprit, and pressure washing is the fastest version of it. A narrow nozzle held close to a joint will strip years of sand in seconds, and the damage is invisible until the surface dries and the joints look sunken. How to clean pavers without losing joint sand covers the technique that avoids this.
Ordinary rain does it more slowly. So does a slope that channels runoff across the field rather than off it, an edge restraint that has failed, and ants that excavate joints from below.
In a wet climate the cycle is predictable. Winter rain moves sand, spring growth fills the gap with moss and weeds, and by late summer the joints look like planters.
Regular sand vs polymeric sand
Two products fill a joint and they behave very differently.
Washed masonry sand is loose, cheap, and forgiving. It compacts into the joint and stays put through friction alone. It moves in heavy water, and it does nothing to stop weeds. Its advantage is that a joint can be topped up in ten minutes with no special conditions.
Polymeric sand carries a binder that activates when wetted, then cures into a firm but flexible joint. It resists washout far better and suppresses most weed germination. It is also unforgiving to install. It must go into a completely dry joint, be swept off the paver faces meticulously, and be watered exactly as the label directs. Haze left on the surface can cure into a film that is genuinely difficult to remove.
Polymeric sand costs several times as much per bag as plain masonry sand, with coverage varying widely by joint width.
When sealing is worth it and when it is not
Sealing earns its cost in three situations. A light-colored paver in a spot that sees food, drinks, or vehicle drips holds stains badly, and a sealer buys time to wipe them up. A field where you want the wet-look color depth will only get it from a sealer. And a joint that has just been polymeric-sanded holds up longer with a compatible sealer over it.
It is a poor investment in three others. On a heavily shaded, constantly damp patio, a film-forming sealer can trap moisture and cloud. On pavers that were never properly cleaned first, the sealer locks the dirt in permanently. And on a surface with active efflorescence, sealing over the salt bloom traps it and makes the white haze worse rather than better. What efflorescence is explains why that white powder keeps returning and why it needs to run its course.
Sealer service life published by manufacturers commonly falls in the two to five year range for a residential patio, shorter on a driveway with vehicle traffic.
The order of work, which is the part people get wrong
- Clean first. Remove organic growth, then let the field dry fully. A cleaner formulated for masonry works better here than force. Sealing over algae seals in algae.
- Pull the weeds and old material out of the joints. Anything you leave becomes a void later.
- Let it dry. Polymeric sand needs a genuinely dry joint. Two to three dry days is a common minimum, and in a wet season that may mean waiting.
- Sand and compact. Sweep in, vibrate or tamp so the sand settles, then top up. Repeat until the joints stay full to about an eighth of an inch below the chamfer.
- Clean the faces. Blow or sweep every grain off the paver surface before any water touches polymeric sand.
- Water per the label, then leave it alone to cure.
- Seal last, if at all, and only after the sand has fully cured. That wait is usually several days to a few weeks depending on the product.
The same logic governs poured slabs, and sealing concrete versus cleaning it again works through whether the reapplication cycle is worth it on a driveway.
What neither one fixes
Sunken or rocking pavers are a base problem. Sand and sealer both sit on top of a failure that is happening underneath, in the compacted gravel and bedding layer. The repair is lifting the affected area, correcting the base, and relaying. No amount of joint material substitutes for that.
Persistent standing water is a drainage problem, and it will destroy joints faster than anything else you do. Fix the water first.
Deep oil that has soaked into a paver is often permanent. A poultice may lighten it. Sealing over it does not remove it.
The broader picture of which outdoor surface needs what treatment is in the exterior surface cleaning guide.
The verdict
Resand whenever the joints are low. It is the cheaper job, it is the one that protects the investment, and skipping it costs far more later in shifted and chipped pavers.
Seal when appearance and stain resistance matter to you, when the field is genuinely clean and dry, and when you are prepared to redo it every few years. It is a maintenance commitment, not a one-time fix.
If you only do one thing, do the sand.
FAQ
Should you seal pavers or just resand them?
Resand first, always. Joint sand is structural and holds the pavers locked together, while a sealer only affects the surface. Sealing is optional and mostly buys stain resistance and color depth. If the joints are low, sanding is the job that matters.
Does sealing pavers stop the sand from washing out?
Only partly. Some sealers bind the top layer of existing joint sand and slow erosion, but a sealer cannot replace sand that has already washed away. Fill the joints properly first, let them cure, then seal if you want the added protection.
How often do pavers need to be resanded?
It depends on drainage, slope, and how the surface gets cleaned. Many residential patios need a top-up every two to four years with regular sand, and longer with polymeric sand. Pressure washing too aggressively can empty joints in a single session.
Is polymeric sand worth the extra cost?
Usually yes, for weed suppression and washout resistance, if you can install it correctly. It requires a dry joint, careful sweeping off the paver faces, and exact watering. Installed wrong it hazes the surface, which is harder to fix than loose sand.
Can I seal pavers that still look dirty?
No. Sealing locks whatever is on the surface underneath the coating, including algae, efflorescence, and stains. Clean the field, let it dry completely, and confirm the color looks right when wet before you commit to a sealer.
How long do you wait to seal after resanding?
Follow the sand manufacturer cure window, which commonly runs several days to a few weeks. Sealing too early traps moisture in the joint and can cloud the finish. Dry, settled weather during that window matters as much as the calendar.
Will a sealer make pavers slippery?
Some film-forming sealers do reduce traction, especially when wet. Products sold for exterior use often offer a matte or textured version, and a grit additive can be mixed in. Check the product description before sealing steps or a pool surround.
Joint sand keeps the patio flat and a sealer keeps it looking new, and they are separate decisions made in that order. If the inside of the house needs the same kind of attention, our house cleaning crews are local and background-checked, with upfront pricing and no hidden fees. Every home is different, so the real number depends on size, condition, and what you want covered. Get a quote and we will walk you through it.
