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Top 5 Filler Materials Contractors Use (and How to Choose the Right One)
At a Glance
Construction fillers and aggregates play a key role in the durability, strength, and longevity of roads and buildings. Whether your project requires cement, epoxy, polyurethane, wood, or asphalt depends on what you want to achieve, as well as the on-site soil conditions and compliance standards you need to meet. The right choice of filler will prevent water damage, cracking, and structural failure, delivering lasting performance.
Why Fillers Are Key To A Construction Project’s Success
As a contractor, a significant part of your work likely involves repairing and fixing existing structures. Road contractors are tasked with repairing potholes and cracks, while building teams may need to undertake periodic maintenance work, such as sealing gaps around doors and windows or fixing loose tiles.
While most people think of heavy plant, asphalt, bricks, and concrete when it comes to construction, the basics have just as much of an impact on the durability and quality of your construction projects.
Choosing the right construction filler and aggregate can be a game-changer, and in this guide, we can help you make the best selection for your project.
At Storefield Aggregate, we understand the role of aggregates and filler materials in shaping the success of construction projects. We’ve seen firsthand how different materials react under varied conditions, and how their efficiency can vary. If you’re looking for quality aggregate bulk bags contact our team today.
What is Filler in Construction?
One of the biggest challenges with road and driveway construction is waterlogging and improper drainage, especially when it comes to its effects on durability and structural integrity. The UK received an average of 1,242 mm of annual rainfall in 2024, making it essential to plan for proper drainage and choose the right material when constructing or repairing roads.
Without proper planning and the correct choice of aggregates and construction filler, water particles become trapped between the large surface particles, resulting in improper binding. The freeze-thaw cycle causes hydrostatic pressure, leading to expansion and cracking, rutting, and pothole formation.
Common lightweight fill materials for road construction include stone dust, lime, fly ash, and cement. These usually measure less than 0.075mm in size, acting as a filler between larger aggregates to form a denser and stronger structure. When combined with bitumen, they increase binding strength and structural integrity. Construction fillers, when used in the sub-base layer, can also prevent shrinkage, especially in soft soil areas.
How to Choose the Right Filler Material
Choosing the right construction filler material is the first step for a well-constructed road, footpath, or driveway. Here are some tips to help you choose the right filler material:
- Understand the type of filler material you want to work with. This will depend on the local soil structure and the construction you’re planning. Choose between low-plasticity, sandy, and clay-based filler materials.
Before placing an order for the material, conduct soil testing and check for plasticity index, moisture content, and grain size distribution.
Read up on any relevant government references and standards, such as BS EN 13055 and BS EN 13043, Specification for High Works (SHW), and the Manual of Contract Documents for Highway Works (MCHW). These standards provide guidelines for grading, plasticity, and moisture sensitivity when using filler material in the UK.
Select your construction filler material based on the specific road layer it will be used in. In sub-base layers, cement or lime fillers are most effective as they reduce plasticity and improve the layer’s load-bearing capacity. For pavement layers, materials such as fly ash or silica fume are preferred for their ability to enhance stability and durability. In bituminous mixes, fillers like limestone dust, hydrated lime, and fly ash are commonly used to strengthen the bond within the mix and increase resistance to deformation under traffic loads.
Choose the material that’s most easily available in your area. Selecting a sustainable material will also help reduce the ecological impact of the construction project.
Top 5 Filler Materials Used in Construction
1. Cement-based Fillers
These construction fillers have a wide range of use cases, including concrete repairs, masonry joints, and grouting. Cement-based fillers are a mix of dry cement, sand, and modifiers and they need to be mixed with water before application.
These fillers are durable, as they’re resistant to weather conditions such as frost and rain, as well as being strong and load-bearing. If you’re after affordable, easily available, and versatile construction materials, cement-based fillers may be the right choice.
2. Epoxy fillers
Epoxy fillers generally aren’t popular in road construction but can be used in other types of construction. When you mix epoxy resin and hardener, you get a durable, waterproof, and excellent bonded solution. Some popular epoxy fillers include colloidal silica, microballoons, milled glass fibre, and wood flour.
Epoxy fillers are more expensive compared to the other fillers on this list and they also require skilled workers for the application. These fillers have limited use cases, however they can be used in adhesive bonding, as well as for gap filling, laminating, and filling smaller holes.
3. Polyurethane Foam Fillers
Polyurethane is a filler material that’s used in insulating projects and for sealing gaps around windows and doors. This lightweight filler material expands on application, becomes rigid once set, and offers soundproofing and heat-retentive properties.
The biggest problem with polyurethane foam fillers is that they’re sensitive to UV rays, as well as being flammable and lacking structural integrity. They can only be used for indoor projects and not for road or building construction.
4. Wood Fillers
If you’re working on carpentry projects and want an aesthetic finish that matches the timber, wood fillers are the best option. This filler material is easy to apply and can help repair cracks, holes, and dents in wooden structures. Just keep in mind that wood fillers lack waterproofing qualities, which can make them less suitable for external use.
5. Asphalt Fillers
Asphalt filler is one of the best lightweight fill materials for road construction. It can also be used in driveway construction, patching, and roof repairs. This filler material is usually composed of bitumen, fine aggregate (such as sand or stone dust), and polymers.
Asphalt filler is characterised by its ability to offer waterproofing, flexibility, improved elasticity, and structural strength. This type of filler is popular in the construction industry because it prevents water penetration and delays the need for the resurfacing of footpaths and roads, as well as being cost-effective and flexible enough to withstand minor temperature differences without leading to crack formation.
Some popular types of asphalt fillers include cold pour fillers, hot pour fillers, and pothole patch mixes.
Contact Storefield for High-Quality Aggregates
Choosing the right construction filler material is key to your project's success, and by using high-quality materials, you offer your clients access to well-constructed roads and buildings. We strongly recommend choosing a trusted aggregate supplier, like Storefield Aggregates, to guarantee access to quality materials at competitive prices.
We’ve been supplying natural and recycled aggregates for over 30 years. Whether you’re building roads, laying foundations, or preparing landscaping projects, you can access materials from our licensed facilities across Northamptonshire.
Our team runs in-house grading and compliance tests and offers rapid delivery. Contact our team today by calling 01536 41821 or emailing us at info@storefield.co.uk to discuss your aggregate requirements.
