Pavers fail from the bottom up. Sunken ruts, rocking pavers and weeds almost always trace back to too little base, poor compaction or bad drainage. Estimate the layers properly and the pavers take care of themselves. This guide works through a paved area from the dig to the joint sand.
The layers
- Excavation: the total depth of every layer plus the paver thickness, minus how high the finished surface will sit above the surrounding ground.
- Sub-grade: the natural ground, compacted. Dig out soft spots and replace them with base material.
- Geotextile on clay or soft soils, to stop the base sinking into the ground below.
- Base: crushed stone or road base, compacted in layers.
- Bedding: about 1" of concrete sand, screeded flat and not compacted.
- Pavers and edge restraint.
- Joint sand: polymeric sand, swept in and vibrated down.
How thick?
| Use | Base |
|---|---|
| Paths and patios | 4–6" |
| Driveways (cars) | 8–12" |
| Poor or clay ground | Add 2–4" and geotextile |
Compact the base in layers no thicker than about 3" with a plate compactor. One thick layer compacted once will settle later, under the pavers.
Fall and drainage
Patios need a fall so water runs away from buildings: about ⅛–¼" per foot (1–2%). Build the fall into the base, not the sand bed; sand that varies in thickness settles unevenly. Keep the finished surface below the sill and clear of weep holes and siding, and where a patio meets a door threshold, add a drainage channel.
Quantities
Pavers: area ÷ (paver + joint module), plus 5–10% waste. Allow 12–15% for herringbone, circles and lots of curves, where every edge piece is a cut.
Base: area × depth, plus about 20% for compaction. Granular A and crusher run are sold by the tonne, at roughly 1.6–1.7 tonnes per cubic metre (about 1.3 tonnes per cubic yard) loose.
Bedding sand: area × bed depth. One cubic yard covers about 324 sq ft at 1", or a tonne of concrete sand about 200 sq ft.
Joint sand: depends on joint width and paver size. A 50 lb bag of polymeric sand covers roughly 30–75 sq ft, depending on joints.
Edging: the perimeter, less any edge already held by a wall or curb.
The paver calculator works out every layer, the joint sand and the edging in one go.
A worked example
A 16 × 12 ft patio (192 sq ft) in 4 × 8 pavers with ⅛" joints: about 4.3 pavers per sq ft, so 830 pavers, plus 10% = 913. Granular A base at 6" plus 20% compaction: 3.3 m³ (4.3 cu yd), about 5.4 tonnes. Bedding sand at 1": 0.6 cu yd, about 0.7 tonnes. Four bags of polymeric sand and 56 ft of edging.
Don't forget
- Removing the dug soil, which swells when dug and takes more truck loads than you'd think
- Plate compactor and block splitter or saw hire
- Drainage channels at thresholds
- Weed membrane where specified
- Sealer for colour and stain protection, if the client wants it
Choosing pavers
Concrete pavers are typically 2⅜" thick for patios and walks, and 3⅛" for driveways. Clay brick pavers are thinner but harder-wearing. Natural stone needs a different bedding method and thicker base on drives. Check the manufacturer's laying guide, which gives the base depth and joint width for each product.
Laying patterns and waste
Stretcher bond (running bond) is the simplest pattern and wastes the least. Basketweave is similar. Herringbone at 45° looks great and locks well under traffic, so it's often used on driveways, but every edge piece is a cut. Circles and fans usually come as kits with their own counts. Price the extra labour for cut-heavy patterns as well as the extra material.
Labour notes
Excavation and base preparation usually take longer than laying. A crew that lays several hundred square feet of blocks in a day might spend two days digging, removing spoil and compacting the base for the same area. Price each stage separately so the client can see where the time goes.
Common questions
Can pavers go straight onto soil?
Not if you want them to stay flat. Without a compacted base they rut, rock and settle within a season or two.
Can I lay over an old concrete slab?
Sometimes, if the slab is sound, falls the right way and leaves room for the paver height below thresholds and damp courses. Water must drain off the slab and out through the edges, so plan drainage holes or channels.
This guide is general information for estimating. It is not engineering, legal or tax advice. Check local codes and your inspector for your project.