What is harcore and what is it used for?

Unsure what hardcore is and want to know whether you’ll need it for your project? Our experts here at Thompson Fuel & Skip Hire are here to share with you all you need to know about hardcore.

What is hardcore?

‘Hardcore’ is a term used to describe a heap of solid materials, generally broken down bits of concrete, stones and bricks – which do not deteriorate or absorb water. It is the creation of construction waste – most of the material is obtained from quarry waste, old building bricks, tiles, slabs and other crushed gravel.

What is hardcore used for?

Hardcore is applied to concrete floors that bear extremely heavy weights. Hardcore is the ideal layer that’s usually applied to driveways, bus depots, car parks and garage floors – for both indoor and outdoor projects. This is used to create a thickness to the oversite, varying between 100mm to 300ml.

This mixture is spread across the surface until it meets the required floor level. The hardcore is then rammed to create a compact bed for a solid, supported floor; ideal for the oversite concrete.

The hardcore bed provides a solid base for all flooring, so it’s important that there’s a strong enough bond between the mixture of materials. If the materials of the hardcore are much too hard and misshapen, they will allow too much water between the gaps and this could weaken the bond. This is why hardcore is generally compressed before it is added to the site – to ensure that the spread is a tightly-knit so that it can offer a solid, weight bearing surface structure.

What to avoid

Avoid hardcore that contains gypsum because this can allow thaumasite, a rock-forming mineral that forms hexagonal crystals around limestone that can be found in the mixture, and this can have an adverse effect and degrade the concrete. Hardcore pieces must be relatively small to prevent any large gaps, because once applied, it’ll need to live up to the job – invest in quality so that it doesn’t undermine its entire purpose.   

What type of hardcore do I need?

As explained above, investing in quality hardcore will ensure the optimal finish and the perfect surface. Ensure that the materials you choose are chemically static, so that the surface is safe for your purposes. You will not want a loose surface that moves around because this could create health and safety issues.

The shape of the chosen aggregates must be small to ensure ideal drainage capability. Aggregates which are too large will create pools of water in between the rubble and if the temperatures are low enough, the water could freeze, expanding the gaps between the hardcore even further. This will crack the surface and the repairs can be costly.

Make sure that the hardcore that’s applied is deep enough to withstand the sheer amount of weight and encourage drainage of rainwater. If the layer is too thin, this will inevitably cause expensive subsidence or cracks.

At Thompson Fuel & Skip Hire, we offer full, comprehensive services including: skip hire, waste management, recycling, hardcore, topsoil and solid fuels. Based in Doncaster, you can also find us located in Armthorpe, Rossington and Bessacarr – so if you need help, call our friendly staff today! We’re here to help you every step of the way.