If you have an existing patio that is showing signs of cracks in the mortar (sand and cement mix) that sits between each paving slab then it’s time to repoint your patio. It’s not uncommon for the pointing (also known as jointing) to fall away completely, causing weeds to grow between your patio slabs.
I get many garden maintenance enquiries asking me to de-weed their patio and often the customer looks confused when I explain that they need their patio repointed. Maybe they think I’m just trying to get extra work from them! But the fact is, if the pointing between your paving slabs is showing signs of cracks, breaks or even has weeds growing through then you need to replace the pointing. After all, this initial time and cost outlay will save time and money in the long run as you won’t need to keep having your weeds removed!
What causes the pointing in your patio to crack and break?
Like anything in life, nothing lasts forever and the pointing between your paving slabs is no exception but there are some factors that determine how long the mortar between each slab should last, although nowadays you have the option of using a paving jointing compound as opposed to the more traditional sand and cement.
I have done a few patio repointing jobs now which involved the addition of repairing loose paving slabs. The reason I mention the loose slabs is because I have noticed on some of these jobs that when the patio was first layed, the landscaper has simply placed a blob of mortor under each corner of the paving slab to save time and money on materials when laying. Not only will this cause lots of patio slabs to become loose over time but the pointing has literally fallen down in between the slabs since there is no proper mortar bed layed.
Most pointing will have a life span of atleast 5 years so if you’ve have a relatively new patio layed in the last couple of years and it’s already showing signs of cracking and breaking away from your paving slabs then it’s most likely due to the way that the mortar was layed. For example, for gaps less than 5mm then fine sand such as building sand should be used for your mortar but anything else it is recommended to use sharp sand although this isn’t essential as I have seen many larger gaps up to an inch thick where building sand has been used and it has made a very strong grout. Another rule of thumb is to use a 1:1 mixture of sand and cement (with the exception of larger gaps where a 3:1 will be recommended) and if you make your mortar mix too dry then your pointing will be lucky to last 6 months. A wet mix will make for a much stronger patio grout but it is alot more time consuming as you run the risk of staining your new patio. I’ll get more into this below.
How to remove your old patio pointing
Before you start repointing your patio you are first going to need to remove the old mortar. I wouldn’t say that this is particularly hard but depending on the quality of your old pointing, it can be very time consuming!
If your old patio pointing is brittle and weak then you may be able to simply rake it out with nothing but a patio scraper like the one pictured below. If this just isn’t possible then it’s time to use an angle grinder – A smaller 4.5″ one will work but I’d recommend using a larger 9″ one with a masonry cutting disc to save time and money since the smaller cutting discs will blunt quicker and need replacing.
Put on your goggles, earmuffs and mask and start by cutting along the inside edge of your paving slab, once cut it’s time to cut on the opposite side of your pointing, along the inside edge of the next patio slab. You may find that the old mortar starts breaking away by itself. It will be a good idea to keep your windows shut as it can get very dusty! You could always hire a water fed angle grinder to help keep the dust down if need be.
Once your pointing has been cut and broken away from your paving slabs then you will need to use your patio scraper to rake out the loose grouting. You will find that your patio will be covered in dust so you may need to wash it down to differentiate between the slabs and the pointing.
When you are happy that you have removed all of the pointing from your patio, I would recommend giving it one last good wash. You’re not going to want to mix your new pointing with the dust.
For a simpler guide on how to remove the grouting from your patio please see below.
- Use your patio scraper to remove the old grout. If the pointing is still strong then cut each side of the mortar, along the inside of the paving slabs with an angle grinder.
- Remove the cut and broken pointing with your patio scraper.
- Sweep up any mess and give your patio a good wash to remove any old dust before giving everything a final check to make sure there are no hidden pieces of mortar wedged between your paving slabs.
How to point your patio
Now that the messy bit is out of the way, it’s time for the fun bit – Pointing your patio! There are essentially 2 ways to do this which include using the traditional sand and cement method or the easier to use paving jointing compound which will save time but comes with a higher price tag.
First, let’s look at the cheaper, more traditional method of using sand and cement. Although this is the cheaper way of pointing your patio, it is more time consuming.
When pointing your patio I find it lasts longest when using a 1:1 (1 part soft building sand to 1 part cement) although I have used a 3:1 ratio (3 parts sand) with no problems. Slowly add water to your mixture until you get a smooth, wet consistency. Be careful not to make it too wet though as it will be almost impossible to point your patio without staining the paving slabs.
Using a pointing trowel, carefully place your mortar into the gaps between the paving slabs and apply pressure whilst giving a smooth finish. Always have a bucket of water and sponge ready to carefully clean any mortar from your paving slabs to prevent staining. It’s due to needing to be careful that this can become a painfully slow way to point your patio.
Some landscape gardeners recommend pointing your patio with a dry mortar mix to prevent staining and add flexibility once set. Let me be the first to tell you that although this will obviously prevent any staining, it won’t take long for the mortar to break up and leave you needing to redo the job again! It’s worth noting that although soft building sand is recommended, you can use sharp sand for larger joints.
I haven’t pointed a patio the traditional way for a couple of years now which is thanks to paving jointing compounds which you can get from any DIY store. In short, all you need to do is open the bag and pour some between the paving slabs and use a pointing trowel to push the jointing compound between the slabs. Since this compound uses a resin instead of cement, all you need to do is use a brush to sweep the jointing compound where it’s needed as there is no risk of staining.
My thoughts on pointing and repointing a patio
The whole process of repointing your patio can seem daunting and if I’m being completely honest, there’s good reason to feel that way. It’s messy and it’s time consuming. But in the long run it’s so worth it!
It’s not a particularly hard job to do but I would recommend a hands on person do it. Using an angle grinder comes with it’s risks and most importantly make sure to wear your PPE! You wouldn’t believe just how much broken grout flicks into your eyes whilst grinding without your goggles on!
It’s one of those jobs that just needs to be done and once it is, you can start enjoying your garden again without the weeds coming through your patio! Even if you just do sections at a time, you’ll get it all done eventually and it saves money compared to paying a professional to do the work for you.
Oh and one last note to add. I would recommend replacing your patio pointing with the paving jointing compound since this won’t run the risk of making a too wet or too dry mortar mix. As well as this, if you ever need to replace any grouting in the future it will be easy to find a colour match since you would just purchase the same tub as well as the fact that I find it easier to remove the jointing compound compared to grinding out old mortar.
As always, if you need any help or advice with pointing or repointing your patio then just comment below as I’m always happy to help!