ᐅ Weeds Growing Between Paving Joint Gaps

Hello,

my big problem:
I have a very large property, and all the paths and the two terraces are paved with interlocking bricks (red old town cobblestones). Everything was done properly; in some areas, there is even a concrete layer underneath the stones. When newly installed, white quartz sand was used for the joints – it looked really great. However, you can hardly see it anymore because we can no longer control the weeds growing there. The property is too large for me to spend all day crawling on my knees (and I wouldn’t be able to) to pull them out.

Because of a built-in pond and also because it is prohibited, strong chemicals are not an option. Using a steam cleaner is very tedious and would also have to be repeated frequently.

Maybe someone has an idea?
I would be very grateful for any advice.

Kind regards

Weeds never grow from below (there’s no soil underneath, whether it’s a gravel bed or concrete); they come from above, carried by the wind and accumulate in the joints.

The best and most expensive option: have the joints scraped out to at least 30 mm (1.2 inches) deep, then refill them with a joint mortar suitable for paving stones. If the joints are in concrete, use a cement-based, water-impermeable joint mortar; for gravel or similar, use a water-permeable mortar, for example based on synthetic resin or plant-binding agents. Fill the joints according to the required width and load conditions, and then you should be free of weeds. I can recommend products like Terrabond from Rost Systembaustoffe or Stones ECO from Stones Baustoffe, which are flexible and don’t crack like rigid joints do.

There is also a cheaper alternative but it’s a never-ending story: chemically treated joint sand with a pH that prevents weed growth. However, over time some joint sand will always wash out, debris carried by the wind will settle on top of the joint, creating fresh soil for weeds. Also, the sand loses its modified pH over time and becomes normal joint sand again. This means every few years you’ll need to sweep out and refill the joints again.

Or you can simply live with the weeds, which actually help to stabilize the joint and prevent washout.

Using a steam cleaner usually makes it worse because it roughens the surface pores of the stone, making it easier for moss, algae, and similar to cling to it.

My neighbor swears by vinegar cleaner... he uses it to treat his grout and claims he hardly has any weeds there. It is biodegradable, although you probably need to do it twice a year.

Vinegar works quite well. I use regular inexpensive vinegar (not a cleaner). It’s a bit more natural than chemical products.
We replaced the old town paving stones with something new. The old town stones have very wide joints due to their rounded tops. Our new stones are laid very closely together and have straight joints.

Does anyone have experience with basalt powder? It is said to work well and is not as expensive as many other specialized joint sands.

I should mention: In many places, using vinegar is prohibited. Depending on the type of stone, vinegar can also damage the paving.

You can also avoid bending down by using a gas torch... Just burn off the stuff.