Unit Weight of Construction Materials

Unit weight or density is used to quantify the weight per unit volume of an object. When it is expressed in the basic SI Unit of mass (kg/m³), it is usually referred to as density, but when expressed in terms of weight (kN/m³), it is usually referred to as unit weight.

Density (kg/m³) = Mass (kg)/Volume (m³)

The unit weight of a material is very important in calculating the self-weight of the material, especially when evaluating the permanent actions in a structure. Without the knowledge of the unit weight of a material, it will be impossible to accurately estimate the bodyweight and the load it subsequently carries when used as a structural member. This article is dedicated to providing a handy list of the unit weight of various construction materials according to EN 1991-1-1:2002.

The density of a material can vary depending on the composition, process of manufacturing, and other factors. However, the density of man-made products is fairly constant (or controllable) when compared with the density of direct products of nature. Therefore, natural materials are expected to have slightly different properties even when they are occurring in the same place.

(a) Unit weight of concrete and mortar

Materials	Density (kN/m3)
Hardened normal weight concrete	24.0
Reinforced concrete (normal percentage)	25.0
Fresh concrete	25.0
Cement mortar	19.0 to 23.0
Gypsum mortar	12.0 to 18.0
Lime-cement mortar	18.0 to 20.0
Lime mortar	12.0 to 18.0

(b) Unit weight of natural stones

Natural Stone	Unit weight (kN/m3)
granite, syenite, porphyry	27.0 to 30.0
basalt, diorite, gabbro	27.0 to 31.0
tachylyte	26.0
basaltic lava	24.0
gray wacke, sandstone	21.0 – 27.0
Dense limestone	20.0 – 29.0
other limestone	20.0
volcanic tuff	20.0
gneiss	30.0
slate	28.0

(c) Unit weight of timber and timber derived products

Timber/timber derived product	Unit weight (kN/m3)
timber strength class C14	3.5
timber strength class C22	4.1
timber strength class C30	4.6
timber strength class D30	6.4
timber strength class D50	7.8
timber strength class D70	10.8
homogeneous glulam GL24h	3.7
homogeneous glulam GL32h	4.2
combined glulam GL24c	3.5
combined glulam GL32c	4.0
combined glulam GL36c	4.2
softwood plywood	5.0
birch plywood	7.0
laminboard and blockboard	4.5
chipboard	7.0 to 8.0
cement-bonded particle board	12.0
flake board, oriented strand board, wafer board	7.0
hardboard, standard and tempered	10.0
medium density fibreboard	8.0
softboard	4.0

(d) Unit weight of metals

Metal	Unit weight (kN/m3)
aluminium	27.0
brass	83.0 – 85.0
bronze	83.0 – 85.0
copper	87.0 – 89.0
cast iron	71.0 – 72.5
wrought iron	76.0
lead	112.0 – 114.0
steel	77.0 – 78.5
zinc	71.0 – 72.0

(e) Unit weight of glass and plastics

Material	Unit weight (kN/m3)
Broken glass	22.0
Glass in sheets	25
Acrylic sheet – plastic	12.0
polystyrene, expanded, granules	0.3
foam glass	1.4
Terracota (solid)	21
Cork (compressed)	4

(f) Unit weight of asphalt/pavement materials

Material	Unit weight (kN/m3)
gussasphalt and asphaltic concrete	24.0 – 25.0
mastic asphalt	18.0 – 22.0
hot rolled asphalt	23.0
sand (dry)	15.0 – 16.0
hardcore	18.5 – 19.5
Quarry dust	14.1

(g) Roofs and roofing materials

Material	Weight per unit area (kN/m2)
Steel roof trusses in spans up to 25 m	1.0 – 2.0
Corrugated asbestos-cement or steel sheeting, steel purlins etc.	0.4 – 0.5
Roofing felt and screed	2.0
Patent glazing (with lead-covered astragals), steel purlins etc.	0.4
Slates or tiles, battens, steel purlins etc.	0.7 – 0.9
Plain roofing tiles	0.6 – 0.9
Interlocking roofing tiles	0.6
0.45 mm gauge aluminium roofing sheet	0.014

(h) Block works, brick works, partitions, and wall finishes

Material	Weight per unit area (kN/m2)
225 mm block work	2.87
150 mm sandcrete block work	2.15
Wall finishes (both sides)	0.6
12 mm plaster rendering	0.3
Two-coat gypsum 12 mm thick	0.215
Plasterboard 13 mm thick	1.1
Gypsum panels 75 mm thick	4.4
Clay hollow block	0.0113 / mm thick
Common clay blocks	0.0189 / mm thick
Engineering clay bricks	0.0226 / mm thick
Refractory bricks	0.0113 / mm thick

(i) Floor finishes

Material	Weight per unit area (kN/m2)
Clay floor tiles	0.575
25 mm thick terrazo floor	0.6
37 mm thick screeding	0.8
Terrazo paving	0.0222 / mm thick
6 mm thick glazed tile + adhesive	0.181
8 mm thick glazed tile + adhesive	0.214
10 mm thick glazed tile + adhesive	0.246
10 mm thick porcelain floor tiles + adhesive	0.275
8 – 10 mm thick vitrified floor tiles + adhesive	0.215
10 mm thick granite floor tiles + adhesive	0.346
12 mm thick granite floor tiles + adhesive	0.4
20 mm thick granite floor tiles + adhesive	0.622