How To Protect Cracks in Concrete from Weeds

Mar 31, 2026

Jamie Unruh

This blog is all about how to protect cracks in concrete from being taken over by aliens, ah, er, vegetation. There’s an adage in the concrete industry that there's two types of concrete: there's concrete that's cracked, and there's concrete that's going to crack.

Cracked concrete is something our team sees on a regular basis. The most common reasons for cracks to show up are due to expansion and contraction of the ground, and soil erosion or compaction.

We’ve covered the solutions for these types of problems in other blog posts, but one issue that has come up with some of our customers is dealing with vegetation (the nice way of saying weeds) growing through the cracks, and sometimes the joints in the concrete.

So, how can you protect your concrete from being taken over by weeds or invasive grass through the cracks of your concrete?

Read on to find out.

"there's concrete that's cracked, and there's concrete that's going to crack."

How Do I Prevent Vegetation from Growing Through Cracks in MyConcrete?

While most people would prefer a pretty flower to grow among the concrete, if anything, the reality is that just does not happen; it’s always the weeds or invasive grasses that creep up.

Tackling the weeds head on is the best way to get rid of them.

Whether mechanically removing the relentless weeds or tenacious grass coming through the crack or using herbicide to kill it, it’s what you do after it’s removed that makes a difference.

Seeds spread through the air on the wind and can germinate with the right conditions. Weeds are persistent and need just a small amount of sunlight and water to grow. They always find a way to survive. So, once the weed is gone, how do you prevent it from coming back?

Filling in the crack where weeds grow is the main solution, and there are many options to address that.

Sand and Silicone

If aesthetics is not a concern, a quick and easy, and fairly inexpensive fix is joint paving sand found at most hardware stores.

This sand has added polymer materials to help seal the gap.Normally it is used for joint paving stones, but it is a great option to prevent weeds from growing through.

The sand gets brushed into each gap between paving stones and is activated with water.

The water activates the properties in that joint paving sand, and essentially strengthens it, making the area a lot more tough and solid where weeds cannot grow.

If weeds are coming in through the joints between paving stones, the fix is similar but sealing with a polyurethane or silicone product instead of sand. These products are usually used for the purpose of keeping water out, and so, the final look is more aesthetically pleasant.

These solutions have the same end game: to prevent anything from penetrating through those cracks or joints.

Preventative Measures

Sealing cracks or gaps in the concrete can be done as a preventative measure as well.

If weeds are known to grow in the area, filling in the cracks before weeds show up can save a bit of headache down the line.

Pesky weeds growing where they shouldn’t be is not a concern that comes up too much with Beyond Group and our clients. Our team typically asks why cracks are there in the first place, and how can we help remedy it?

Going back to that catchphrase at the beginning of this article: there's concrete that's cracked, and there's concrete that's going to crack, let's look into why cracks are so inevitable.

"Tackling the weeds head on is the best way to get rid of them."

The Freeze Thaw Cycle

Almost all concrete cracks eventually. It can start out as a very thin hairline crack whether in a slab or a control joint, and over time, especially with constant expanding and contracting with the weather, the cracks will get bigger.

Control joints are what is put in place into the concrete when the concrete is fresh. These joints are troweled in to try and isolate anticipated cracking.The control joints also serve an aesthetic purpose.

The expansion and contraction happen every so slightly, but it’s enough that over time it does cause some displacement so that cracks appear in those joints.

Settling Down

The other main reason that concrete cracks is because it’s trying to settle.

The soils below the concrete can self-compact over time or erode with water, which creates an unstable concrete slab. That slab under its own weight or when introduced new weight with vehicles or furniture on top, puts additional pressure on that unstable concrete slab and that eventually gives way under pressure.

This is a pretty typical scenario that our team at Beyond Group sees, which is why we're so pleased to offer deep foam injections to help stabilize concrete like the example above.

Ultimately, no one can really prevent cracks from occurring; we encounter it often. Whether expanding and contracting subsoils, or water drainage causing erosion, or natural ground compaction causing settling, concrete isn’t infallible.

Those cracks while ugly can also be invaded by weeds or grass that make the concrete work look, well, shabby. Removing the weeds and filling in the cracks or joints with paving sand, silicone or other concrete filling materials will prevent the repeated appearance of weeds.

If cracks keep appearing in your concrete, it’s time to call a professional and find out what’s causing it.

Thankfully, most concrete issues can be repaired. Our concrete lifting team at Beyond Group is more than happy to discuss your concrete problems and help find a solution. Give us a call today!

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