So, you’ve decided to lay down some paving slabs, and you’re wondering what the best material is to fill the gaps between them. 

With various options available, it can be a daunting task to decide on the right one. But worry not, we’re here to help! 

In this article, we’ll discuss the various types of fillers, factors to consider, how to choose the best one, and some application tips

Let’s get started!

Types of Fillers

Cement Mortar

Cement mortar is a traditional choice for filling gaps between paving slabs. It’s made by mixing sand, cement, and water to create a thick, paste-like consistency.

This strong, durable option can withstand heavy loads and is particularly suitable for high-traffic areas.

Polymeric Sand

Polymeric sand is a modern alternative to cement mortar. It consists of fine sand mixed with polymer additives, which form a flexible, water-resistant bond when activated by water.

This material is easy to apply, resists weed growth, and is less prone to cracking or breaking than cement mortar.

Jointing Compounds

Jointing compounds are another option for filling gaps between paving slabs. These ready-to-use products come in various formulations, such as epoxy resins or brush-in compounds.

They provide a long-lasting, flexible, and weather-resistant joint that requires minimal maintenance.

Factors to Consider


The cost of different fillers varies, so consider your budget when choosing the best option. Cement mortar is generally the cheapest, while polymeric sand and jointing compounds can be more expensive but offer additional benefits.

Aesthetic Appeal

The appearance of your paving project is essential, so choose a filler that complements your slabs. Cement mortar and jointing compounds can be coloured to match or contrast with your paving, while polymeric sand is available in a range of shades.


The filler you choose should be able to withstand the wear and tear of everyday use. Cement mortar is strong but can crack over time, while polymeric sand and jointing compounds provide a more flexible, long-lasting solution.


Some fillers require more maintenance than others. Cement mortar may need to be repaired or replaced if it cracks, while polymeric sand and jointing compounds are relatively low-maintenance options.

How to Choose

Assess Your Needs

Consider the specific requirements of your project, such as load-bearing capacity, weather resistance, and weed control. This will help you identify which filler best meets your needs.

Compare Options

Research the pros and cons of each filler and compare them based on your criteria. This will help you make an informed decision.

Test a Sample

If possible, test a small sample of your chosen filler to see how it performs under real-world conditions. This will give you an idea of its suitability for your project before committing to a large-scale application.

Application Tips

Proper Preparation

Ensure that the area between the paving slabs is clean and free of debris before applying the filler. Proper preparation will help the filler adhere better and last longer.

Follow the Manufacturer’s Instructions

Each filler type may have specific application instructions, so be sure to read and follow the manufacturer’s guidelines for the best results.

Keep Weather in Mind

Consider the weather when planning your project. Some fillers may require dry conditions for proper curing, while others may be more forgiving. Check the manufacturer’s recommendations and plan accordingly.

In Summary

In conclusion, the best filler for your paving slabs depends on various factors, such as budget, aesthetic appeal, durability, and maintenance. 

Cement mortar, polymeric sand, and jointing compounds each has their pros and cons.

To make the best decision, assess your needs, compare your options, and test a sample if possible. And don’t forget to follow the application tips for a successful project!


Can I mix different fillers for my paving project?

It’s generally not recommended to mix different fillers, as they may have different properties and may not bond well together. Stick to one type of filler for a consistent and reliable result.

How often should I replace or repair the filler between my paving slabs?

The frequency of maintenance depends on the filler type and the conditions it’s exposed to. Regularly inspect your paving and address any issues as they arise to prolong the life of the filler.

Can I use the same filler for all types of paving slabs?

While some fillers may be suitable for various paving materials, it’s essential to check the manufacturer’s recommendations to ensure compatibility with your specific slabs.

Is it possible to change the colour of the filler after it’s been applied?

Some fillers, like cement mortar and jointing compounds, can be coloured during the mixing process. However, changing the colour after an application is generally not possible without removing and replacing the filler.

How do I remove old filler from between paving slabs?

The removal process will depend on the type of filler used. In most cases, you’ll need to chisel or scrape away the old filler, taking care not to damage the paving slabs. Once the old filler is removed, clean the area thoroughly before applying the new filler.

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Passionate about helping households transition to sustainable energy with helpful information and resources.

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