What do you put between paving slabs?
The lines in between your patio slabs are called ‘joints’, and they’re an indispensable part of any paving system.
When filled right, they keep the structure stable and make your slabs far less inviting for invasive weeds. If your jointing is failing (or was applied improperly), you’ll be forever topping up, scrubbing stains or chasing loose flags.
That’s why we have patio grout, designed to make life easier (and paving more secure).
There isn’t one ‘best’ product: every patio is different, and the grout you’ll need to pick will depend on what you’ve laid and how it’ll be used.
So, if you’ve ever wondered, ‘what do you put between paving slabs?’ and ‘how can I choose the right grout?’, join Ovation Landscaping on our latest deep-dive.
What is patio grout?
Patio grout is the material that fills the gaps between your slabs.
When done well, grouting should be unnoticeable: your patio will drain water well, and weeds will struggle to take hold. But patio grout’s primary purpose is to stabilise the paving and protect it from shifting or weathering damage.
You might see it marketed as ‘patio grout’, ‘jointing compound’, and sometimes ‘pointing’: this variability can be confusing, particularly if you’re purchasing it for the first time.
The term ‘grout/jointing compound’ refers to the material you put into the joints after the paving is laid. They usually come as brush-in or wash-in mixes that bind themselves without you having to hand-trowel every joint.
Mortar is the traditional sand-and-cement mix used to ‘point’ joints securely. It’s still common, just slower and more technique-sensitive. ‘Pointing’ is the act of filling those joints (new work). ‘Repointing’ is what must be done if it fails.
What are the main types of patio grout?
If you’re wondering ‘what do you put between paving slabs when power, stability, or quickness is the main priority?’, retailers like Ovation Landscaping have a grout for every situation.
When you’re choosing a product, it really comes down to how you want to apply it and what the paving needs to cope with. Below are the main options we stock and some recommendations for where they make sense:
Brush-In
Brush-in compounds are the quick, tidy option for most patios. You open the tub, sweep the grout into the damp joints, compact it, then rinse off. Our ProJoint RapidFlow range is specifically designed for porcelain but can also be used on natural stone.
It’s available in the core UK colours – Basalt, Mid-Grey, Light Grey, Neutral, and Black. Match or contrast your slabs for a more exciting end result.
Slurry
Slurry (wash-in) systems are mixed wet and squeegeed across the surface, then rinsed clean. They’re popular on porcelain because they flow right into the joint and cure hard without you having to hand-point every gap.
If you’re comparing methods, we’ve got a handy explainer on brush-in vs squeegee to help you pick the best approach.
Epoxy
When you need staying power (e.g., on busy walkways, driveways, anywhere joints are exposed to heavy cleaning), step up to epoxy: an exceptionally strong product typically made of pre-mixed sand and resin, which you then combine with an enclosed hardener.
As a two-part resin system, our ProJoint TITAN products are suitable for natural stone, concrete paving and anywhere that brush-in compounds aren’t quite enough.
Traditional Mortar
The conventional method of pointing a patio is using a mixture of sand and cement. The typical mix is 4 parts sharp sand to 1 part cement. Some users recommend including building sand in the mix as well. The colour can be customised by adding a colour tone.
It still has a place on heritage stone or where you’re matching existing work – homeowners should just budget more time for mixing, packing and tooling each joint.
What determines the right grout for your patio?
Slab material
The type of stone used for your patio slabs can influence the choice of grout, particularly if you’re concerned about potential staining and the strength of the bond between the slab and the jointing material.
Porcelain, for example, is dense and low-porosity, so it prefers purpose-made porcelain paving grouts: either brush-in compounds that specify porcelain on the label, or slurry/epoxy systems designed to cure cleanly.
All types of grout are generally suitable for natural stone, but care must be taken to avoid staining. These slabs work well with resin ‘brush-in’ compounds or traditional sand-and-cement pointing.
Gap size
As different products are designed for specific gap sizes, homeowners must accurately measure the joint. Ready-mixed brush-in compounds are typically designed for joints within a specific range, for instance, between 5mm and 20mm in width and from 20mm in depth.
If your joints are tighter than intended (common with some porcelain layouts), consider using slurry or epoxy grouts formulated for narrow joints.
Traffic
Matching the product to the load will ensure your grout lasts.
For typical garden patios (pedestrian only), a quality brush-in compound is ideal. Where joints are subject to heavier wear, such as busy paths, commercial vehicles, or vehicular loads, we recommend using a high-strength resin or epoxy.
Traditional mortar still works for rigid, heritage looks, but it’s less tolerant of movement.
Weather
Weather conditions are equally crucial for the long-term performance of your grout.
Using sand and cement mortar requires dry weather with no risk of frost for application and curing. Applying it in wet conditions can be messy (and lead to staining). If it dries out too quickly in the hot sun, it can become weak and fall apart.
A big advantage of ready-mixed, brush-in compounds is that they can often be applied in both wet and dry conditions. In fact, the application process for some products requires the paving to be thoroughly soaked with water to aid the process.
Shop with Ovation Landscaping for jointing and grouting compounds!
So, what do you put between paving slabs? Grout! It’s the simplest answer we can give, but that’s because every paving project is different.
If you’ve laid porcelain with neat 2–20 mm joints, go for our porcelain paving grouts. They’re purpose-made for low-porosity slabs and sized for those tighter gaps. Looking for quick and tidy installation?
Our ProJoint RapidFlow brush-in range is the easy option: sweep it in, compact, rinse off, and you’re done. When you need something tougher, our ProJoint TITAN two-part epoxy jointing compound will withstand more demanding use.
FAQ’s
Is it worth sealing a patio?
It depends on the patio.
On porcelain, sealing is usually unnecessary because it’s non-porous. On natural stone, a breathable sealer can reduce staining and make cleaning easier, but only when applied in a properly dry weather window to avoid trapping moisture.
For easier upkeep, definitely consider sealing, but skip it if conditions aren’t ideal.
How do you fill gaps between paving slabs?
It’s simple: follow the manufacturer’s instructions closely. Just check that you have the right joint width/depth for the product you’ve chosen.
How much can I expect to pay?
Coverage varies by joint size and the size of the surface area to be grouted.
When should I call a professional?
You should consider calling a professional for high-strength epoxy systems or for porcelain slurry grouting (to avoid staining).