Bedding sand is a thin, even screed — 25 to 40 mm, and no more. Most people order two or three times what they need because they are using sand to level ground that the base should have levelled. This works out both the bedding and the jointing sand, and tells you when the answer is less sand.
Bedding sand under block paving and flags, plus the jointing sand that goes between them. Enter the paved area and the screed depth.
Works in metric and US imperial — you choose at the start and can switch at any time. Every figure this calculator uses is published with its source, and the result comes with a printable order sheet. No account, no email, and nothing you type leaves your browser.
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25 mm screeded even, capped at 40 mm. ICPI Tech Spec and the CMHA construction specification are unambiguous about it. Most people order two or three times what they need because they are using sand to level ground that the base should have levelled — and a thick sand bed is exactly what makes paving go wavy a year later. A 20 m² patio at 25 mm is about 0.6 m³ of bedding sand, roughly 1.1 tonnes. If your sum is coming out at three times that, the problem is the base.
Screed at 25 mm and you finish nearer 19 mm once the plate compactor has been over the pavers. That is what the allowance on this page is — consolidation, not waste. It also means you cannot judge the finished level from the screeded level, which is another reason the base has to be right before any sand goes down.
Concrete or sharp sand, not soft sand: ICPI requires bedding sand to meet the ASTM C33 concrete-sand grading, and the British equivalent is a sharp or grit sand to BS EN 12620. Never screed until the base is finished and compacted — sand screeded and then walked on is sand that has to be screeded again. Put the falls in the base, not the bedding layer.
25 mm screeded even, and no more than 40 mm. ICPI Tech Spec and the CMHA specification both say so. It is a laying course, not a levelling course — if you are using sand to correct an uneven base, the paving will move.
Concrete or sharp sand meeting the ASTM C33 grading, or a sharp or grit sand to BS EN 12620 in Britain. Not soft building sand, which is too fine and holds water.
Buy a bag, do a trial area, and scale from that. Coverage swings with joint width and paver thickness far more than any calculator can predict, and the bag knows better than we do. Polymeric jointing sand has its own coverage figures, so follow the pack.
Almost always because the depth entered is too deep. At the correct 25 mm, a 20 m2 patio needs only around 0.6 m3. If the sum is three times that, sand is being used to level ground that the base should have levelled.