How to Estimate Paving and Block Paving Quantities
Introduction
Paving is a layered assembly disguised as a surface. What you see is the paver; what makes it last is the sub-base, the bedding layer and the edge restraint. A takeoff that counts only the pavers produces a driveway that looks right for one wet season and then ruts, settles and sheds its surface.
The arithmetic is straightforward once the layers are separated: pavers by area with pattern waste, sub-base by compacted volume converted to tonnes, bedding sand by area, and restraint by linear metre. This guide works through all four with examples in metric and imperial, and covers the failures that show up when one of them is skipped.
What a paving takeoff contains
A complete estimate for block paving has these lines:
Pavers, by area, format and pattern
Sub-base aggregate, by compacted volume and delivered tonnes
Bedding sand, by area
Jointing sand, by area
Edge restraint or kerbs, by linear metre, with bedding concrete
Geotextile, by area, where the sub-grade is fine-grained
Drainage, if the surface falls to a gully or a soakaway
Plant: plate compactor, wacker, cutting equipment
Waste removal of excavated material
Each is a real order. Most first estimates carry the first two and forget the jointing sand, the geotextile and the disposal.
Measure the area, including the awkward parts
Measure the finished paved area, plan dimensions, including any area under a border pattern. For regular shapes this is length × width. For everything else, break it into rectangles and triangles and add them.
L-shapes: two rectangles
Curves: approximate with a series of chords, then add 5% because the outer curve wastes more
Circles and rings: area of the outer circle minus the inner
Sweeping driveways: measure the centre line length × average width
Deduct areas that are not paved: planting beds, manhole covers larger than about 0.5 m², and building footprints. Add back the area occupied by any small cover that the pavers must cut around, because those cuts consume material.
Pavers per square metre
Pavers are sold by the square metre in packs, and each format has a fixed number per square metre:
Format
Per m²
Typical use
|---|---|---|
200 × 100 mm
50
Standard block paving
225 × 112.5 mm
39.5
Metric modular
300 × 150 mm
22.2
Larger block, driveways
300 × 300 mm
11.1
Patios, pedestrian
400 × 400 mm
6.25
Patios
600 × 300 mm
5.55
Contemporary paving
600 × 600 mm
2.78
Large-format paving
Work from the pack coverage rather than the individual count, exactly as with tiles. A pack described as 10 m² is 10 m² regardless of how many units it holds.
Pattern waste is the difference between one order and two
The laying pattern sets how much material is destroyed at the edges:
Pattern
Waste
|---|---|
Stretcher bond, straight edges
5%
Herringbone, 45°
10-12%
Herringbone, 90°
8-10%
Basket weave
8-10%
Circles, fans, curved borders
15-20%
Any pattern with a contrasting border
Add 5%
Herringbone is the strongest pattern for driveways because the interlock resists lateral load, and it is also the pattern that consumes the most material at the perimeter. That trade is worth making on a driveway and unnecessary on a garden path.
Sub-base: the layer that decides whether it lasts
The sub-base is compacted granular material that spreads load into the ground. Its depth depends on use and ground condition:
Use
Compacted depth
|---|---|
Garden path, pedestrian
75-100 mm
Patio, pedestrian
100 mm
Domestic driveway, cars
150-200 mm
Driveway, occasional van
200-250 mm
Light commercial, delivery vehicles
250-300 mm
Soft ground adds depth. On clay, silt or made ground, increase the sub-base by 25-50% or improve the sub-grade first. This is not padding: a driveway on clay with 100 mm of sub-base will rut within a year.
Now the conversion that causes most of the arithmetic errors: compacted volume is not loose volume. A granular sub-base compacts by 20-30%. To achieve 150 mm compacted, you must place roughly 190-200 mm of loose material, and the tonnes delivered are calculated from the compacted volume at the material's compacted density.
Worked example, metric
A driveway 9.0 m long × 4.0 m wide, herringbone, 200 × 100 mm pavers, 175 mm compacted sub-base.
Area = 9.0 × 4.0 = 36 m²
Pavers at 8-12% waste for herringbone: 36 × 1.10 = 39.6 m², so 40 m², or four 10 m² packs
Sub-base compacted volume = 36 × 0.175 = 6.30 m³
Sub-base tonnage at a compacted density of 2.1 tonnes/m³ = 13.2 tonnes, so order 14 tonnes and expect a small surplus
Bedding sand at 40 mm = 36 × 0.04 = 1.44 m³, about 2.3 tonnes, so 2.5 tonnes
Jointing sand: 36 m² at 3-4 kg/m² = 125 kg, order 4 bags of 25 kg plus spare
Edge restraint: perimeter = 2 × (9.0 + 4.0) = 26 m, plus 2 m for the opening, so 28 m of edging on a concrete bed
Worked example, imperial
The same driveway as 29 ft 6 in × 13 ft 1 in, 7 in of compacted sub-base:
Area = 29.5 × 13.08 = 386 sq ft, or 35.9 m², so 40 m² of pavers with waste, as above
Sub-base compacted volume = 386 × (7 ÷ 12) = 225 cu ft = 6.37 m³
Sub-base tonnage = 13.4 tonnes
Bedding sand at 1.5 in = 48 cu ft = 1.36 m³
Edging perimeter = 85 ft, plus the opening
The two methods differ by less than a percent, which is the check worth doing whenever a supplier quotes in one unit and you measured in the other.
Edging and restraint: the line that is always missing
Pavers are a flexible surface held together by interlock and by the edge. Without a rigid edge, the pattern spreads under load and the joints open.
Edge restraint is measured in linear metres around the full perimeter, including both sides of any opening. It sits on a concrete bed, typically 100 mm deep and 150 mm wide, and is haunched with concrete on the outside face.
Kerbs, where used, are a separate item: units counted, bedding concrete by linear metre, and haunching. On a driveway connecting to a road, the kerb is often the authority's detail and its cost is fixed by specification rather than by choice.
Jointing, compaction and the finishing sequence
The finishing sequence consumes material and cannot be short-cut:
Compact the sub-base in layers of no more than 100 mm
Blind the bedding sand, screed to a consistent 30-40 mm
Lay the pavers, keeping the pattern true
Cut the edge courses and any obstructions
Compact the surface with a plate compactor, at least two passes
Brush kiln-dried sand into the joints, then compact again
Top up the joints after a week of settlement
Stage 6 and 7 are where jointing sand is consumed. Budget it as a separate line, and expect to return once.
Drainage and fall
A paved surface must shed water. A fall of 1 in 60 to 1 in 80 away from buildings is typical, and on a driveway it usually runs to a channel, a gully or the road.
If the paving is permeable, the specification changes: open-graded sub-base, no bedding sand, and a geotextile separating layers. Permeable paving costs 20-40% more in material and considerably more in sub-base depth, so it is not a like-for-like substitution.
Where the paving falls towards a building, a linear drainage channel is a line item measured in metres, with an outlet and a connection.
Compaction plant and cutting
A plate compactor is essential and is often hired by the day. A block splitter or a diamond blade saw is needed for edge cuts; on a herringbone driveway with curves, cutting can be 10% of the labour.
Hire costs belong in the estimate. So does disposal of the excavated material, which on a 36 m² driveway with 175 mm of sub-base is around 6-7 m³ of spoil, or a skip.
Costing and comparing quotes
Normalise paving quotes into five lines: pavers, sub-base, bedding and jointing sand, edging and restraint, and labour with plant. Then check the sub-base depth, because that is where a cheap quote hides.
A quote that specifies 100 mm of sub-base on a clay driveway is not a cheaper version of one specifying 200 mm. It is a different product with a shorter life, and the difference in cost is smaller than the cost of rebuilding it.
A driveway that falls to the road
The most common layout problem is a driveway that must drain without flooding the road or the neighbour's boundary. Where the surface falls towards the street, a linear channel along the threshold collects the water and discharges to a gully or a soakaway.
That channel is measured in linear metres, with a grate, an end outlet and a connection. On a 4 m wide driveway it is 4 m of channel plus the connection, and it is often the difference between an approved and a refused application. Price it as a line, not as an allowance.
Common failures and what they cost
No edge restraint: the pattern spreads, joints open, replacement of the whole area
Sub-base too thin: ruts along wheel tracks within a season
Bedding sand too thick: the pavers rock and settle unevenly
No geotextile on fine sub-grade: the sub-base migrates into the clay and the surface sinks
Joints not filled: water enters, the bedding softens, and the surface fails in freeze conditions
Wrong sand in the joints: river sand washes out, kiln-dried sand locks
Each of these is a few percent of the original cost to prevent and most of the original cost to repair.
Block paving versus concrete, resin and gravel
Paving is not one product, and the takeoff structure changes with the choice.
In-situ concrete is priced by volume plus reinforcement plus finish, and it has no joint sand or pavers. It is cheaper per square metre on large areas and far less forgiving of ground movement; a crack is permanent.
Resin-bound or resin-bonded aggregate is a thin surface over a bound base, priced by area with the resin as the dominant cost. It needs a sound, free-draining base and it cannot be patched invisibly.
Gravel is the cheapest material and the most expensive surface to keep. It needs a stabilising grid or it migrates, and the grid is a separate line measured in square metres.
Block paving sits in the middle: material cost per square metre is higher than concrete, installation is slower, and it can be lifted and relaid after a service trench. On a driveway with buried services, that recoverability is worth more than the price difference.
Frequently asked questions
How many pavers per square metre? 50 for 200 × 100 mm blocks, 39.5 for 225 × 112.5 mm, 11.1 for 300 × 300 mm. Work from the pack coverage where possible.
How deep should the sub-base be for a driveway? 150-200 mm compacted for cars, more on soft ground, and 250 mm or more for regular delivery vehicles.
How much waste should I allow for block paving? 5% for a straight stretcher bond, 8-12% for herringbone, and up to 20% for circles and curved borders.
Do I need edging on a patio? Yes, unless the paving is restrained by a wall on every side. Loose perimeters always spread.
How much bedding sand? 30-40 mm, screeded to a consistent depth. Thicker bedding is less stable, not more forgiving.
Can I lay pavers on sand alone? Only for a temporary path. Any trafficked surface needs a compacted sub-base and a restrained edge.
Estimate it with FRELUX
The FRELUX paving calculator takes the area and pattern, returns pavers, sub-base tonnage, bedding and jointing sand and edge restraint, and prices them from your local price book. Enter the use and the ground condition and the sub-base depth is applied for you.