Exposed Aggregate Calculator
Estimate concrete, sealer and surface retarder quantities for an exposed aggregate driveway or path.
Exposed Aggregate Calculator
Estimate materials for an exposed aggregate driveway or path, including sealer.
Estimating Exposed Aggregate Materials
Exposed aggregate concrete uses a surface retarder applied during placement to slow the setting of the top layer of cement, which is then washed or brushed away to reveal the stone aggregate underneath. This calculator estimates the concrete volume using area (m²) × thickness (m), and separately estimates the sealer and retarder needed to finish and protect the surface.
Sealer and surface retarder are both estimated at one drum of each per 70 m², a typical coverage rate for standard products, with a minimum of one drum for smaller areas.
What Information You Need To Enter
Enter your project area in square metres and slab thickness in millimetres (100 mm is standard for most driveways and paths).
Understanding Your Results
You will see the concrete volume required, and the number of sealer and retarder drums needed. Actual coverage rates vary by product brand and aggregate exposure depth, so check your chosen product's specification sheet for larger jobs.
Why Accurate Estimating Matters
Sealer and retarder are speciality products with their own cost and lead time separate from standard concrete supply, so knowing quantities in advance helps you order everything together and avoid a delay waiting on an extra drum.
Frequently Asked Questions
What is surface retarder used for?
Surface retarder is applied to the top of freshly poured concrete to slow the curing of that top layer, allowing it to be washed or brushed away afterward to expose the aggregate beneath.
Why does exposed aggregate need sealing?
Sealer protects the exposed stone surface from staining, weathering and moisture penetration, and typically enhances the colour and finish of the aggregate.
How often does an exposed aggregate driveway need resealing?
This depends on the product used and traffic exposure, but many sealers are recommended for reapplication every few years to maintain protection and appearance.
Can any concrete be finished as exposed aggregate?
The aggregate size and type in the concrete mix affects the final look, so it is worth discussing your desired finish with your concreter before the pour so the right mix is ordered.
Is exposed aggregate more expensive than plain concrete?
Yes, typically, due to the additional materials (retarder, sealer) and labour involved in exposing and finishing the surface. Request a free quote for an accurate comparison for your project.
Related Calculators & Services
Need An Exact Price, Not Just An Estimate?
The Exposed Aggregate Calculator gives you a fast, useful planning figure. For a fixed, accurate price backed by a site assessment, request a free professional quotation from HPL Construction.
