Planning a Paver Patio Base

Measure the length and width of the finished patio surface. A common backyard example is 10×12 ft (about 3.0×3.7 m), which is 120 sq ft. Mark that shape on the ground before you dig so the excavation matches the paved area plus edge restraint.

Add a little width for the edge restraint (plastic, aluminium, or concrete curb) if it sits outside the paver field. Skipping that detail is how people run short on gravel when the trench grows wider than the sketch.

Decide slope early — usually a gentle fall away from the house for drainage. The base layers follow that slope; they are not a flat pancake that you tip later with sand alone.

Most residential patios need about 4–6 in (100–150 mm) of compacted crushed stone over firm soil. Driveways and soft clay sites often need more. Compacted depth is what matters; loose dumped depth is taller before you run the plate compactor.

Use the Gravel Calculator with patio area and the compacted depth you chose. For a 10×12 ft patio at 5 in compacted base, you are looking at 10 × 12 × (5/12) ≈ 50 cu ft, or roughly 1.85 yd³ before any over-excavation. Order a bit extra for compaction and uneven dig — often 5–10%.

Geotextile between soil and stone helps on clay or silty ground by limiting mixing. It does not replace depth or compaction. Angular crushed stone locks better than rounded pea gravel for a structural base.

About 1 in (25 mm) of coarse concrete sand or screed sand sits on the compacted gravel — some specs allow up to about 1½–2 in, but thicker sand beds tend to shift. This layer is for fine levelling, not for fixing a bad gravel grade.

The Sand Calculator handles that thin volume. On the same 10×12 ft patio at 1 in of sand, volume is about 10 cu ft (under 0.4 yd³). It looks small next to the gravel, but running short mid-screed stops the whole job.

Do not use play sand or fine masonry sand that will not screed flat. Screed to the finished elevation with pipes or rails, then pull them and fill the voids before pavers go down.

Count pavers from patio area, paver face size, joint width, and waste. A straight running bond on a rectangle needs less waste than a diagonal or herringbone lay. The Paver Calculator covers the top layer only — it does not add gravel or bedding sand for you.

Example: 10×12 ft with 6×9 in pavers. Face area per paver is 54 sq in (0.375 sq ft), so 120 ÷ 0.375 = 320 pieces before joints and waste. Joints reduce the count slightly; waste adds it back. With 10% waste you might order around 350 pieces, then round up to full bundles.

Polymeric or jointing sand goes in after the pavers are set and compacted — different product from bedding sand. Budget it by coverage chart on the bag, not by guessing from the bedding sand total.

Total dig depth is roughly paver thickness + sand + compacted gravel, minus how much the finished surface should sit above the surrounding grade. A 2⅜ in paver over 1 in sand and 5 in gravel is already more than 8 in of stack before you account for finished height.

Edge restraint keeps the field from creeping outward. Without it, the perimeter opens and the base unravels. Include spikes, concrete haunch, or curb materials on the shopping list next to the three main layers.

UK projects often specify MOT Type 1 (or similar) for the sub-base in millimetres; US yards talk in inches of crushed stone. Same job, different labels — convert depths once and keep the Gravel Calculator and Sand Calculator on matching units.

Straight lays: plan around 5–10% waste. Diagonals and complex borders: 10–15% is safer. Mixed sizes and circles need a cut diagram, not just area math.

Order all pavers from one batch when colour consistency matters. Keep a few extras for future repairs. Bundle counts rarely match your exact piece count — round up to what the supplier sells.

Price gravel, sand, and pavers as three lines in the Cost Estimator if you are comparing DIY versus a landscaper quote. A lump sum that only lists “pavers” may hide a thin base.

Laying pavers on dirt or on a thin sand-only bed looks fine for a month and fails after the first wet season. Compacting the soil alone is not a substitute for crushed stone depth.

Using bedding sand to correct a wavy gravel surface pushes problems upward. Fix the gravel grade, compact again, then screed a consistent sand thickness.

Skipping slope away from the house traps water against the foundation. Fix drainage in the base plan, not with a last-minute tip of the sand screed.