Glossary
The words this handbook uses for sand, gravel, stone and soil, what they mean, and every page that mentions them.
See also: Material list
Aggregate
Sand, gravel and crushed rock used in building. Its size, shape and washing decide how it behaves.
Explained in 1 Basics
Mentioned in (4 pages): 1.1 1.3 1.4 5.3
Sources: EN 12620:2002+A1:2008, Aggregates for concrete · USGS Bulletin 1594, Natural aggregates of the conterminous United States
All-in aggregate
Sand and stone in one material, starting at 0 and stopping at 45 mm or less, for example 0–16.
Explained in 1.1 Reading a sieve size
Mentioned in (2 pages): 1.1 1.5
Sources: EN 12620 overview, Spanish Ministry of Public Works
Backfill
Material put back into the dig-out next to a foundation or wall, in compacted layers, so the ground does not settle.
Explained in 2.2 Backfill against foundations and walls
Mentioned in (9 pages): 1.2 2.1 2.2 2.4 6.4 9.1 9.5 9.6 10.3
Sources: Prince William County, Foundation backfill policy · US Bureau of Reclamation, Pipe bedding and backfill
Base
The compacted layer of crushed stone with fines under paving, a slab or a gravel surface. It carries the load and spreads it onto the ground.
Explained in 3.1 Base for patios, paths and sheds
Material list: Crushed stone with fines
Mentioned in (37 pages): 1.1 1.2 1.3 1.4 2.3 2.4 3.1 3.2 3.3 4.1 4.3 5.1 5.2 6.2 6.3 6.5 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 8.1 8.2 8.3 8.4 8.5 9.1 9.3 9.4 9.5 9.6 9.7 9.8
Sources: Oregon State University Extension, Installing pavers · UK Specification for Highway Works, Series 800 · UK government, Guidance on the permeable surfacing of front gardens
Bedding sand
The thin, even layer of loose sand that pavers and slabs are compacted into until they sit level. It is never used to level the base.
Explained in 3.3 Sand bedding under paving
Mentioned in (10 pages): 1.1 1.2 3.1 3.2 3.3 4.1 7.5 7.6 7.8 8.4
Sources: ACT Government, Standard specification 12: segmental paving · Oregon State University Extension, Installing pavers
Bulk density
Weight per volume of a heap or a layer, in t/m³. The loose and the compacted values differ, so use the right one to turn m³ into tonnes.
Explained in 1.4 Ordering the right amount
Mentioned in (5 pages): 1.4 5.3 8.2 9.2 10.1
Sources: FHWA Federal Lands, Earthwork design
Bulking of sand
Damp sand takes up more room than dry sand, most at about 4–6 % moisture, so damp sand measured by volume gives less sand than it seems.
Explained in 1.4 Ordering the right amount
Mentioned in (1 pages): 1.4
Sources: Virtual Labs (IIT Delhi), Bulking of fine aggregate
Capillary break
A layer of clean, coarse stone under a floor slab. Water climbs up through soil and fine sand, but not through the large gaps between stones.
Explained in 6.1 Capillary break
Mentioned in (6 pages): 1.1 1.2 1.3 2.3 4.1 6.1
Sources: US DOE Building America Solution Center, Capillary break beneath slab · Extent of capillary rise in sands and silts (Western Michigan University thesis)
Coarse aggregate
Stone with a largest size of 4 mm or more and a smallest size of 2 mm or more, for example 4–8 or 16–32.
Explained in 1.1 Reading a sieve size
Material list: Stone and gravel
Compaction
Pressing a layer with a plate compactor or roller so the grains pack tighter. Thick layers stay loose at the bottom, so compact in thin layers.
Explained in 2.3 Structural fill
Mentioned in (44 pages): 1.1 1.2 1.3 1.4 1.5 2.1 2.2 2.3 2.4 3.1 3.2 3.3 3.4 4.1 4.3 4.4 5.3 6.1 6.2 6.3 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 8.1 8.2 8.3 8.4 8.5 8.6 9.1 9.3 9.5 9.6 9.7 9.8 10.1 10.4 10.7
Sources: US DOT, Equipment and lift thickness optimization for structure backfill · HAUC (UK), Reinstatement specification, compaction table
Compost
Decomposed plant material worked into soil to add organic matter. Raised beds are filled with a mix of topsoil and compost.
Explained in 10.4 Soil for flower beds
Material list: Compost
Mentioned in (6 pages): 7.5 10.2 10.3 10.4 10.5 10.7
Sources: Colorado State University Extension 7.235, Choosing a soil amendment · University of Minnesota Extension, Raised bed gardens
Concrete
Cement, water, sand and stone mixed into a mass that sets hard and carries load.
Explained in 4 Concrete
Material list: Ready-mixed concrete
Mentioned in (29 pages): 1.1 1.2 1.3 1.5 2.1 2.2 3.1 3.2 3.3 4.1 4.2 4.3 4.4 5.2 5.3 6.1 6.5 6.6 7.1 7.5 7.6 7.7 7.8 8.4 8.5 9.1 9.7 9.8 10.4
Sources: FAO Farm Structures, ch. 3: Concrete · FHWA Highway Materials Engineering Course, Cement and water in concrete
Crushed stone
Rock, boulders or large cobbles broken in a crusher. The angular grains lock together, so a crushed base is more stable under load than one of rounded gravel.
Explained in 1.2 Crushed or rounded
Material list: Crushed stone with fines
Mentioned in (29 pages): 1.2 1.3 1.4 2.3 3.1 3.2 3.3 3.4 6.2 6.3 7.2 7.3 7.4 7.5 7.6 7.7 8.1 8.2 8.3 8.4 8.6 9.1 9.2 9.3 9.5 9.6 9.7 9.8 10.1
Sources: USGS Bulletin 1594, Natural aggregates of the conterminous United States · TxDOT, Flexible base guidelines
Curing
Keeping new concrete damp and sheltered so it gains strength: at least 7 days. Leaving the forms on helps keep it damp.
Explained in 4.4 Casting in formwork
Mentioned in (4 pages): 4.4 5.1 5.3 7.7
Sources: Mile High Flood District, Concrete curing specification · FAO Farm Structures, ch. 3: Concrete
Decomposed granite
Granite weathered into coarse sand and grit, also called DG. Moistened and compacted, it makes a firm path.
Explained in 8.3 Decomposed granite path
Material list: Path gravel with fines
Mentioned in (4 pages): 7.3 8.3 8.5 8.6
Sources: US National Park Service, City of Rocks: geological trail station 1 · Brisbane City Council, Standard drawing BSD-5213: decomposed granite path
Filter layer
A layer of sand, grit or geotextile between fine soil and coarse drainage stone. It lets water through but holds the soil back, so the stone does not silt up.
Explained in 6.6 Filter layer
Mentioned in (4 pages): 1.3 2.4 4.1 6.6
Sources: USDA NRCS, National Engineering Handbook 633 ch. 26, Sand and gravel filters · Caltrans Geotechnical Manual, Geosynthetics
Fines
Grains that pass a 0.063 mm sieve: silt, clay and rock dust. US standards such as ASTM C33 use 0.075 mm (the No. 200 sieve).
Explained in 1.3 Washed or unwashed
Mentioned in (39 pages): 1.1 1.2 1.3 1.4 1.5 2.1 2.2 2.3 2.4 3.1 3.2 3.3 3.4 4.1 5.1 6.1 6.2 6.3 6.5 6.6 7.2 7.3 7.4 7.5 7.6 7.7 7.9 8.1 8.2 8.3 8.4 8.6 9.1 9.2 9.3 9.5 9.6 9.7 9.8
Sources: EN 12620:2002+A1:2008, Aggregates for concrete · ASTM C33-03, Concrete aggregates
French drain
A trench with a perforated pipe in clean stone, wrapped in fabric and laid to a fall of 0.5–1 %. It carries water from wet ground to an outlet or a soakaway.
Explained in 6.4 Drainage trench
Material list: Drain pipe
Mentioned in (3 pages): 6.4 6.5 6.6
Sources: US DOE Building America Solution Center, Swales, drains and site grading · Washington State University Extension, Improving drainage
Frost depth
How deep the ground freezes in winter. It depends mainly on winter air temperatures, then on the soil, its moisture, snow and ground cover.
Explained in 2.4 Frost protection layer
Mentioned in (4 pages): 2.1 2.4 4.2 4.3
Sources: US HUD / NAHB Research Center, Frost-protected shallow foundations
Frost heave
The ground lifting when water in fine soil freezes. It needs freezing, a frost-susceptible soil and water; take one away and it stops. Coarse sand and clean gravel do not heave.
Explained in 2.4 Frost protection layer
Mentioned in (3 pages): 2.4 4.2 8.2
Sources: National Research Council Canada, Building Digest 26: Ground freezing and frost heaving
Frost protection layer
A layer of sand or gravel that does not lift when it freezes, so the ground under a slab, path or light building stays still in winter.
Explained in 2.4 Frost protection layer
Mentioned in (3 pages): 2.4 3.2 7.1
Sources: National Research Council Canada, Building Digest 26: Ground freezing and frost heaving
Gabion
A wire mesh basket filled with stone, for walls, fences, benches and planters. The stones must be larger than the mesh, usually 100–200 mm.
Explained in 9 Garden walls and gabions
Material list: Gabion stone
Mentioned in (9 pages): 1.1 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8
Sources: US Department of Defense, UFGS 31 36 00 Gabions · USDA NRCS Construction Specification 464, Wire mesh gabions
Geotextile
A permeable fabric laid between soil and stone. It lets water through and keeps the soil out of the stone. Non-woven fabric filters best.
Explained in 6.6 Filter layer
Material list: Geotextile
Mentioned in (20 pages): 2.2 2.3 2.4 4.1 6.2 6.3 6.4 6.5 6.6 7.2 7.4 7.5 7.9 8.1 8.3 8.5 9.3 9.5 9.6 9.8
Sources: Caltrans Geotechnical Manual, Geosynthetics · Minnesota Stormwater Manual, Materials under permeable pavement
Graded
A spread of sizes from small to large, so the small grains fill the gaps between the big ones. Material like this, with its fines, compacts into a dense layer.
Explained in 1.1 Reading a sieve size
Mentioned in (9 pages): 1.1 1.4 3.1 3.2 5.1 5.2 5.3 6.5 9.3
Sources: ACI Education Bulletin E1-07, Aggregates for concrete · Washington State Department of Ecology
Grading sheet
The producer's declared grading: the percentage of the material passing each sieve. It shows how much is oversize, undersize and fines.
Explained in 1.1 Reading a sieve size
Mentioned in (4 pages): 1.1 1.3 1.5 6.6
Sources: EN 12620:2002+A1:2008, Aggregates for concrete · ASTM D448-12 (Government of Bermuda copy)
Jar test
Shake sand or soil with water in a straight-sided jar and let it settle. Coarse grains settle first and fines last, so the layers show what the material is made of.
Explained in 1.3 Washed or unwashed
Mentioned in (2 pages): 1.3 10.6
Sources: Manitoba government, Jar test field guide for sand · Clemson University HGIC, Soil texture analysis: the jar test
Jointing sand
Dry fine sand, such as 0–2 mm, swept into the gaps between pavers. Full joints lock the pavers together so they do not shift.
Explained in 3.4 Filling paving joints
Material list: Joint sand
Mentioned in (5 pages): 1.1 3.1 3.2 3.4 7.6
Sources: Bedford Borough Council, Kerbs, footways and paved areas · ACT Government, Standard specification 12: segmental paving · Oregon State University Extension, Installing pavers
Loam
Soil with a balanced mix of sand, silt and clay. Sandy loam to loam is preferred for lawns.
Explained in 10.6 Testing your soil
Mentioned in (6 pages): 1.3 10.1 10.2 10.5 10.6 10.7
Sources: Colorado State University Extension, Estimating soil texture · Clemson University HGIC, Soil texture analysis: the jar test · University of Idaho Extension CIS 1062, Starting a home lawn
Mortar
Sand, cement and often lime mixed with water, for laying bricks and blocks. Mixes are given by volume, such as 1 : 1 : 6.
Explained in 5.1 Laying bricks and blocks
Mentioned in (7 pages): 1.1 1.2 1.3 5.1 5.2 7.6 7.8
Sources: NA to BS EN 1996-1-1, UK National Annex to Eurocode 6
Permeable paving
Paving that lets rain through the joints into a layer of washed stone, which stores the water while it soaks into the ground.
Explained in 6.2 Permeable layer
Mentioned in (14 pages): 1.1 1.3 3.2 3.3 3.4 6.2 6.3 6.6 7.1 7.2 7.4 7.6 7.9 8.6
Sources: Minnesota Stormwater Manual, Materials under permeable pavement · UK government, Guidance on the permeable surfacing of front gardens
pH
How acid or alkaline a soil is; 7 is neutral. About 6.5 suits most gardens. A laboratory test is more reliable than a home kit.
Explained in 10.6 Testing your soil
Mentioned in (3 pages): 10.2 10.4 10.6
Sources: Royal Horticultural Society, Soil pH and testing · Montana State University, Soil test kits
Pipe bedding
The bed under and the fill around a buried pipe or duct. It carries the pipe evenly along its length and keeps hard points off it.
Explained in 2.1 Pipe and duct bedding
Mentioned in (3 pages): 1.1 2.1 6.4
Sources: US Bureau of Reclamation, Pipe bedding and backfill
Plate compactor
A vibrating steel plate run over a layer to compact it. A heavier plate compacts a thicker layer; a light one needs thinner layers.
Explained in 2.3 Structural fill
Mentioned in (26 pages): 2.2 2.3 2.4 3.1 3.2 3.4 4.1 6.2 6.3 7.2 7.3 7.4 7.5 7.6 7.7 7.9 8.1 8.2 8.3 9.1 9.3 9.5 9.6 9.7 9.8 10.1
Sources: HAUC (UK), Reinstatement specification, compaction table · US DOT, Equipment and lift thickness optimization for structure backfill
Render
A sand, cement and lime coat on a wall, put on in two or three coats, each thinner than the one before. If it dries too fast, it cracks.
Explained in 5.2 Rendering a wall
Mentioned in (4 pages): 1.1 1.2 1.3 5.2
Sources: Spelthorne Borough Council, Mortars, plasters and renders · US National Park Service, Preservation Brief 22: Stucco
Rounded gravel
Natural sand and gravel, smoothed while rivers or glacial meltwater carried it, and dug mainly from river, glacial and beach deposits. The round grains do not interlock as well as crushed ones.
Explained in 1.2 Crushed or rounded
Material list: Stone and gravel
Mentioned in (18 pages): 1.1 1.2 1.5 2.1 3.3 4.1 4.2 4.3 4.4 6.1 6.4 7.2 7.4 7.8 8.1 8.2 9.2 9.8
Sources: USGS Bulletin 1594, Natural aggregates of the conterminous United States · TxDOT, Flexible base guidelines
Sand
Fine aggregate: grains from 0 up to 4 mm at most, for example 0–2 or 0–4.
Explained in 1.1 Reading a sieve size
Material list: Sand
Mentioned in (35 pages): 1.1 1.2 1.3 1.4 1.5 2.1 2.4 3.1 3.2 3.3 3.4 4.1 4.2 4.3 4.4 5.1 5.2 5.3 6.1 6.2 6.6 7.1 7.4 7.5 7.6 7.8 7.9 8.3 8.4 9.1 9.2 10.2 10.5 10.6 10.7
Screed
A level sand–cement layer on top of a concrete slab, ready for the floor finish. To screed is also to draw a straight board along rails to level sand or concrete.
Explained in 5.3 Laying a floor screed
Mentioned in (15 pages): 1.1 1.3 3.1 3.2 3.3 4.1 5.3 6.2 7.4 7.5 7.6 7.7 8.4 9.1 9.3
Sources: Public-sector works specification for screeds and plaster (UK Contracts Finder) · Oregon State University Extension, Installing pavers
Self-binding gravel
Crushed gravel with its fines and a little clay left in, laid damp and compacted until it sets firm.
Explained in 8.2 Self-binding gravel path
Material list: Path gravel with fines
Mentioned in (6 pages): 7.3 8.1 8.2 8.3 8.5 8.6
Sources: University of Copenhagen (IGN), Self-binding gravel · Building crusher fines trails (USDA Forest Service, via American Trails)
Sieve size
Two numbers in mm that name a smaller and a larger sieve. 8–16 mostly passes a 16 mm sieve and mostly stays on an 8 mm sieve. Standards write it d/D, as in 8/16.
Explained in 1.1 Reading a sieve size
Mentioned in (28 pages): 1.1 1.5 2.1 2.2 2.3 2.4 3.1 3.2 3.3 3.4 4.1 4.2 4.3 4.4 5.1 5.2 5.3 6.1 6.2 7.2 7.3 7.4 7.5 8.1 8.2 8.3 8.4 9.1
Single-size
A narrow size such as 8–16 with no fines. About 30–40 % of the volume stays open, so water runs through, and washed stone like this will not compact tightly.
Explained in 1 Basics
Mentioned in (7 pages): 1.2 1.4 4.1 6.1 6.5 7.4 7.6
Sources: Oregon State University Extension EM 9204, Soakage trenches · University of Kentucky AEN-108, Permeable pavement · Washington State Department of Ecology
Soakaway
A pit filled with clean stone that holds rainwater from a roof or paving and lets it seep into the ground. Keep it at least 5 m from buildings.
Explained in 6.5 Soakaway
Mentioned in (5 pages): 1.1 6.4 6.5 6.6 7.1
Sources: Hastings Borough Council, Soakaway advice note · Washington State University Extension, Improving drainage · Oregon State University Extension EM 9204, Soakage trenches
Soil texture
The share of sand, silt and clay in a soil. Find it with a jar test or by pressing moist soil into a ribbon between your fingers.
Explained in 10.6 Testing your soil
Mentioned in (2 pages): 10.5 10.6
Sources: Colorado State University Extension, Estimating soil texture · Clemson University HGIC, Soil texture analysis: the jar test
Structural fill
Crushed stone with fines, placed and compacted in thin layers to raise the ground under a slab, paving or a light building. Good compaction keeps it from settling later.
Explained in 2.3 Structural fill
Mentioned in (6 pages): 1.1 1.2 1.3 2.3 2.4 7.1
Sources: US DOT, Equipment and lift thickness optimization for structure backfill · HAUC (UK), Reinstatement specification, compaction table
Sub-base
The lower layer of compacted crushed stone under a drive or road, laid on the subgrade. In the UK the standard sub-base is called Type 1.
Explained in 3.2 Base for driveways
Mentioned in (11 pages): 1.1 1.2 1.3 3.1 3.2 6.2 7.1 7.4 7.5 8.2 8.3
Sources: UK Specification for Highway Works, Series 800 · UK government, Guidance on the permeable surfacing of front gardens
Subgrade
The firm natural ground that the first layer is built on, with topsoil and soft patches dug out.
Explained in 7.7 Concrete driveway
Mentioned in (3 pages): 7.7 8.2 9.3
Sources: BRANZ Bulletin 412, Concrete driveways · Iowa DOT Standard Specifications §2431
Subsoil
The soil under the topsoil, below the colour change. Keep it apart from topsoil when you dig and store soil.
Explained in 10 Garden soil
Material list: Dug soil and subsoil
Mentioned in (4 pages): 2.3 10.1 10.2 10.4
Sources: Defra (UK), Code of practice for the sustainable use of soils on construction sites
Topsoil
The uppermost layer of soil, with the most organic matter. For lawns and beds, never under a load.
Explained in 10 Garden soil
Material list: Topsoil
Mentioned in (19 pages): 1.3 2.2 2.3 3.1 3.2 4.1 6.1 6.4 7.5 7.7 8.1 8.2 9.3 9.5 10.1 10.2 10.4 10.5 10.7
Sources: University of Connecticut, Purchasing topsoil · Defra (UK), Code of practice for the sustainable use of soils on construction sites
Voids
The open space between the grains. Washed single-size stone is about 30–40 % voids, and that space is what stores and carries water.
Explained in 6.5 Soakaway
Mentioned in (3 pages): 6.2 6.5 7.4
Sources: Oregon State University Extension EM 9204, Soakage trenches · University of Kentucky AEN-108, Permeable pavement
Washed
Rinsed with water to remove the fines. Concrete and drainage need clean, washed material. Washed stone will not compact tightly, so bases and fill keep their fines.
Explained in 1.3 Washed or unwashed
Mentioned in (36 pages): 1.1 1.2 1.3 1.4 1.5 2.1 2.2 2.4 3.1 3.2 3.3 3.4 4.1 4.2 4.3 4.4 5.1 5.2 5.3 6.1 6.2 6.3 6.4 6.5 6.6 7.2 7.4 7.5 7.6 7.8 7.9 8.1 8.2 8.4 9.1 9.6
Sources: ASTM C33-03, Concrete aggregates · Washington State Department of Ecology
Water–cement ratio
The weight of water in a mix divided by the weight of cement. A higher ratio makes concrete weaker.
Explained in 7.7 Concrete driveway
Mentioned in (1 pages): 7.7
Sources: FHWA Highway Materials Engineering Course, Cement and water in concrete
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