How to stop weeds growing between paving slabs


I went to price up a job today where the man explained that he wanted his old patio removed with new paving slabs laid due to the weeds growing in between the paving slabs themselves. I couldn’t believe that he wasn’t aware of any cheap fix which would stop this from happening in the future and after a conversation, he has now gone ahead with a jet wash and re-pointing. But it begs the question…How exactly do you stop weeds from growing in between your paving slabs? What if you have block paving? Can you ultimately stop the weeds from growing here too? Lets look at which options actually work, as well which options are permanent solutions or temporary solutions!

weeds in patio

Will weed killers stop weeds from growing between my paving slabs?

If weed killers didn’t work, then no company would be able to sell them, right? But that doesn’t mean that this is a permanent solution…in fact I have never agreed with weed killers because it’s not an instant fix, meaning that it takes time for the weeds to die off, and they always come back! Even when it comes to using weed killers on your flower beds, it’s best to remove them by hand and regularly turn the soil over instead of constantly paying out for weed killers which also means risking the health of your loved plants and lawn. So although in theory weed killers will kill the weeds on your patio, it won’t stop new weeds from growing between your paving stones. This is the case whether that be a patio, block paving, driveway, flower beds or anywhere else for that matter.

What if I remove the weeds from my patio by hand?

Removing weeds from in between your paving slabs isn’t a bad idea. It gives the immediate transformation that you are looking for compared to using weed killer, as well as not carrying the risk of damage to other plants and other adverse effects on the environment. But is there a downside? Absolutely! If weeds grew in between your paving stones before then they will grow again, and the last thing you want to do is be on your hands and knees on a monthly basis removing the weeds from your patio.

How do I stop weeds growing between my paving slabs?

With any patio, you will usually have a gap between each flag stone which is filled with cement when laid. Over time, this cement weakens causing gaps in between the paving slabs and allowing for seeds to fall and grow which is when the problems begin! The longer you leave the slabs, the more the pointing (also known as jointing) or cement will crack and break which means more weeds! Some weeds can really be stuck too, where simply pulling them out only breaks the leaves and leaving the root still in tact.

Ultimately, you need to remove all of the broken cement and weeds before re-pointing between the paving slabs. Not everyone knows this, but if you have natural paving such as Indian sandstone, then it’s best that you give your patio a jet wash every couple of years as well as sealing the area. Failure in this will result in black spots, also known as lichen which can be extremely hard to remove and may require chemicals. Don’t assume that having a patio means no maintenance as this simply isn’t the case. You can find out more about black spots on your patio by clicking here. Lets look at the steps needed to stop these weeds from growing in between your paving slabs!

  1. Have your patio jet washed. If your patio is covered in black spots then it may be worth hiring a professional who may have a more powerful pressure washer. Otherwise a cheap and cheerful jet washer will do the job. Try to remove as much cement in between the paving slabs as possible whilst using the jet washer. Lots of pressure washers will come with a dirt blaster attachments which is best for this. The reason that this needs to be done first is to not risk blowing out any of your new pointing when finished.
  2. At this point you should have removed most of the weeds, if not all of them. If there are some stubborn ones left then try pulling them out by hand, and if not try using small tools such as a tile scraper to slice in between the paving stones. Do the same for any pointing (cement) left behind, the use of a chisel and hammer may do the job well. If the pointing seems strong in some areas then you are welcome to leave it be, just be aware that your new pointing won’t match in color.
  3. Now that you have a clean patio with no weeds or pointing in the way, it’s time to re-point! In a bucket, mix (preferably) building sand and cement to a 3:1 mix. This means for every 3 sharp sand that you put into the bucket, add just 1 cement. Don’t mix it too wet as you will stain your patio, the trick that I tend to use is to have it just wet enough that when you squeeze it, it will stain your hands. So just add a little water each time until this happens. Just damp will be enough. If you are feeling brave, then the wetter the mix the stronger the pointing and the longer it will last. You can use a pointing trowel like in the video below as well as a brush to prevent staining.

What if I have weeds growing in between my block paving?

This is a common problem, since over time every driveway will get weeds eventually! The problem is that unlike patios that are typically laid on sand and cement, block pavers are actually laid on nothing but sand. And where patios have cement in between each paving stone, block pavers have nothing but sand again, or kiln dried sand to be precise. It is actually a fair bit easier to remove the weeds and prevent them from growing again on driveways where block paving has been used since all you need to do is jet wash the area which will remove the weeds quite easily, but please find a jet wash with a dirt blaster attachment. Most Karchers come with this attachment.

Once you have jet washed the area, you will notice that a lot of kiln dried sand has also blown out. This is normal, but you do need to sweep in new sand to prevent new weeds from growing as well as prevent each block paver from moving. It’s best to purchase a weed free kiln dried sand which is slightly more expensive that the standard kiln dried sand but will last longer. All you need to do is throw it down on your driveway and sweep in using nothing but a broom! Nice and easy!

I’ve been asked before to just use a wire brush, but honestly it’s just not worth the aggravation. Do it properly and worry no more! At least for the next couple of years anyway!

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