If weeds keep showing up in the same joints no matter how many times you pull them, the weeds themselves are not really the problem. They are a symptom of what is happening underneath the surface of your driveway or patio, and until that gets fixed, new ones will keep finding their way through.
This guide covers why the weeds show up in the first place, why the usual fixes do not last, and what actually stops them for good.
It is a call we get often, and usually the driveway or patio in question has gone years without a wash or a fresh joint of sand. The fix is rarely complicated once you know what is actually happening below the surface.
Why weeds show up in the joints in the first place
Interlock pavers are held together by sand packed into the joints between them. Over time, rain and regular washing carry that sand out, and once a joint is even partly empty, it becomes the perfect spot for a seed to land, take root and grow. Organic matter like leaves, dirt and grass clippings also settles into those same open joints, which gives weeds an even easier start.
So a driveway or patio that is growing weeds along every joint line is usually telling you the original sand has washed out, not that your soil is somehow worse than your neighbour's.
Why pulling them or spraying them never actually works
Pulling weeds by hand takes the plant out but leaves the open joint exactly as it was, empty and ready for the next seed. Spraying kills what is growing today but does nothing about the gap that let it grow in the first place. Both are treating the plant, not the joint, which is why the same spots keep producing weeds season after season no matter how often you deal with them.
Why sanding without the wash is a waste of money
It might sound like the fix is just brushing new sand into the joints, but sanding on its own without pressure washing first is pointless, because the weeds, old sand and dirt still sitting in the joint come right back through whatever gets brushed over them. If a job is worth doing, it is worth doing properly, which means the wash always comes first.
The two day process that actually stops it
Day one is the wash. We pressure wash between every crack and across the face of the stones, blasting out the old sand, dirt, weeds and any hidden ant activity in the joints. Then the surface has to dry completely before anything else happens, since wet joints ruin polymeric sand.
Day two is the sand. We brush new polymeric sand into every joint until it is packed full and level, blow off anything loose so it does not haze on the stones, then mist it in light passes with water so it hardens in place. For the full breakdown of both days, see our guide on how polymeric sanding actually runs, step by step.
What to expect once it is done
Once the joints are packed and set, the weeds stop, since there is no open gap left for a seed to root in. The stones stop shifting underfoot, the colour comes back, and any ant activity that was living in those same hollow joints tends to move on too. If ants specifically are what brought you here, our guide on ants in your interlock pavers covers exactly why that happens and what to expect after the joints are locked back down.
It is usually good for 3 to 5 years, and if weeds come through earlier than that, our seasonal guarantee covers a free touch up. Stay off the surface for 24 hours after the sand goes in so it has time to set properly.
How to tell if your joints have already failed
A few signs tell you it is time before the weeds even show up. Gaps or sunken joints where the level of sand has visibly dropped below the paver surface. Stones that shift or wobble when you walk across them. Ant hills appearing in the cracks, which is its own sign covered in our guide on ants in your interlock pavers. And sand that visibly washes out across the surface after a heavy rain.
Any one of those on its own is worth a look, and most driveways showing weeds are also showing at least one of the others. Send us a photo of what you are seeing and we will tell you plainly whether it is time for a full wash and resand or something smaller.
What we do differently on the visit itself
We knock or text when we arrive, then walk the whole area before anything gets touched. Anything light still sitting on top of the joints, like planters or patio furniture, we move clear ourselves and put back before we leave, and we rinse the edges as we go so nothing runs off onto a neighbour's lawn. None of that is billed separately, it is part of doing the wash properly rather than working around the obstacles left on the surface.
By the time we get to the sanding on day two, every joint has already been cleared down to bare stone, which is the only way new sand actually bonds and holds rather than sitting loosely on top of whatever was left behind. Skipping that thoroughness on day one is exactly how a resand job ends up failing within a single season instead of holding for years.
