A TERM PAPER

ON

THERMAL PROPERTIES OF POPULAR BUILDING MATERIALS IN NIGERIA

BY

ASHIRU MONSURU OLATUNDE

(ARC/05/5596)

COURSE- ARC 810

(APPLIED CLIMATOLOGY)

MENTOR: PROF. OGUNSOTE, O.O.

SEPTEMBER, 2011

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TABLE OF CONTENT

TITLE PAGE NUMBER

1.0 INTRODUCTION 1

2.0 POPULAR BUILDING MATERIALS IN NIGERIA 2

2.1 CONCRETE 2

2.2 LATERITE 2

2.3 STONE 3

2.3.1 REQUIREMENTS OF GOOD BUILDING STONES 3

2.4 TIMBER 4

2.5 METALS 6

2.6 PLASTICS 7

2.7 GLASS 7

3.0 THERMAL PROPERTIES OF BUILDING MATERIALS IN NIGERIA 8

3.1 ABSORPTIVITY 8

3.2 SPECIFIC HEAT 9

3.3 THERMAL CONDUCTIVITY 9

3.3.1 CONDUCTANCE VS CONDUCTIVITY 10

3.4 DIFFUSIVITY 12

3.5 THERMAL DIFFUSIVITY 12

3.6 THERMAL MASS 13

REFERENCES 15

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LIST OF FIGURE

Figure 1: Thermal diffusivity measurement apparatus. 13

LIST OF TABLES

Table 1: Selected Nigerian timber species and their uses in building construction 5

Table 2: Thermal Properties of Building Material at Room Temperature 8

Table 3: Building Materials And Their Thermal Conductivity For Dry (Indoor) And Wet

(Outdoor) Conditions. 10

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1.0 INTRODUCTION

The aim of design with climate is to maintain comfort within buildings. Thermal design

of buildings for thermal comfort requires an understanding of the basic thermal properties of

building materials. Komolafe (1988) opine that Climatic factors do not affect people's comfort

alone, they can also impair the safety of buildings and lead to building damage and premature

fatigue of building materials. Heat transmission and absorption by building materials is affected

by the absorptivity, the conductivity and thermal capacity of the materials. These properties of

materials determine the characteristics of wall and roof elements and therefore the way they will

modify the thermal environment. In tropical region for instance, with reference to Nigeria,

materials like zinc, aluminum and asbestos are commonly used in form of sheets for roofing in

modern building constructions, but these materials have a high ability to conduct heat (solar

radiation) into the interior space of a building, a situation that causes discomfort in indoor space

in dry season.

The heat flow through any building material is dependent on the thermal properties of the

material (Akpabio et al., 2001). It can therefore be deduced that the heat generated indoor

depends solely on the rate of heat conducted through the building materials used for the

construction. Materials used in walls, floor and other sun-exposed parts of the house should have

adequate thermal storage or reflectance, that is, thermal properties able to respond to the needs of

the climate where the building is located. Hence, the problem is not only what is readily

available and economically affordable to the people, but also what is thermally desirable and

efficient.

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2.0 POPULAR BUILDING MATERIALS IN NIGERIA

Building material is any material which is used for a construction purpose. Many

naturally occurring substances, such as clay, sand, wood and rocks, even twigs and leaves have

been used to construct buildings. The popular building materials in Nigeria are laterite, stone,

concrete, timber, metal, plastics, bamboo, and glass.

2.1 CONCRETE

Concrete is a composite building material made from the combination of aggregate and a

binder such as cement. The most common form of concrete is Portland cement concrete, which

consists of mineral aggregate (generally gravel and sand), portland cement and water in

predetermined proportions. After mixing, the cement hydrates and eventually hardens into a

stone-like material. When used in the generic sense, this is the material referred to by the term

concrete. Additional materials called admixture may be added to influence the properties of

concrete. Concrete as building material is very good in compression (Fullerton, 1979)

2.2 LATERITE

Laterite is a porous soil ranging from soft earthly material to hard rock. It ranges in

colour from white to dark red, depending on the amount of iron in the soil. Laterite is found in

areas of high temperatures with high rainfall and well defined rainy season (Fadamiro and

Ogunsemi, 1996). Products of laterite include brick, compressed laterite blocks, tiles, pipes,

sanitary wares, etc. It has the following properties.

Laterite hardens on drying (e.g. sundried block)

At a very high temperature, it melts and when it cools, it produces a very hard, semi-

vitrified building material.

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2.3 STONE

Stone is a natural resource available in most parts of the world often with low cost of

extraction and is generally usable without further processing other than cutting and simple

dressing.

2.3.1 REQUIREMENTS OF GOOD BUILDING STONES

The following are the requirements of good building stones:

(i) Strength: The stone should be able to resist the load coming on it. Ordinarily this is not of

primary concern since all stones are having good strength. However in case of large structure, it

may be necessary to check the strength.

(ii) Durability: Stones selected should be capable of resisting adverse effects of natural forces

like wind, rain and heat.

(iii) Hardness: The stone used in floors and pavements should be able to resist abrasive forces

caused by movement of men and materials over them.

(iv) Toughness: Building stones should be tough enough to sustain stresses developed due to

vibrations. The vibrations may be due to the machinery mounted over them or due to the loads

moving over them. The stone aggregates used in the road constructions should be tough.

(v) Specific Gravity: Heavier variety of stones should be used for the construction of dams,

retaining walls, docks and harbours. The specific gravity of good building stone is between 2.4

and 2.8.

(vi) Porosity and Absorption: Building stone should not be porous. If it is porous rain water

enters into the pour and reacts with stone and crumbles it. In higher altitudes, the freezing of

water in pores takes place and it results into the disintegration of the stone.

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(vii) Dressing: Giving required shape to the stone is called dressing. It should be easy to dress so

that the cost of dressing is reduced. However the care should be taken so that, this is not be at the

cost of the required strength and the durability.

(viii) Appearance: In case of the stones to be used for face works, where appearance is a

primary requirement, its colour and ability to receive polish is an important factor.

2.4 TIMBER

The wood that is suitable for building or other construction purposes is called timber.

When sawn into various market forms like beams, battens and planks, etc., it is called converted

timber. Timber and other wood products have, for ages, remained one of the major structural

materials for building construction worldwide due to their renewable nature, availability in

various sizes, shapes and colours, affordability, relatively high fatigue resistance and specific

strength, ease of joining, durability, and aesthetic appeal (Goldstein, 1999). Also, un-serviceable

wooden building components are re-cyclable either for their structural properties, e.g., reused

permanently as framing or temporarily as form-work, or for their heat content as fuel.

Timber is a material that provides much better thermal insulation than the metals or

concrete; it has higher ratios of strength and stiffness to weight than the other major materials; it

is relatively easy to work and to join requiring only simple tools; and in certain circumstances it

has high durability (Keenan and Tejada, 1984). In Nigeria, the major area of structural utilization

of wood is in roof construction, with the building industry alone consuming about 80% of the

country’s estimated 20 million cubic meters of annual lumber production (Alade and Lucas,

1982, Lucas and Olorunnisola, 2002).

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Table 1: Selected Nigerian timber species and their uses in building construction

Building Component Recommended Timber Species

Carcassing Afara (Terminalia superba),), Albizia (Albizia spp.), Alstonia (Alstoniaboonei), Celtis (Celtis spp.), Dahoma (Piptadeniastrum africanum), Danta(Nesogordonia papaverifera), Ilomba (Pycnanthus angolensis), Iroko(Milecia excelsa), Obeche (Triplochiton scleroxylon)

Door and window frames(external)

Agba (Gossweilerodendron balsamiferum), Albizia (Albizia spp.), Apa(Afzelia africana), Danta (Nesogordonia papaverifera), Gedu Nohor(Entandrophragma angolense), Iroko (milecia excelsa), Lagos Mahogany(Khaya ivorensis), Opepe (Nauclea diderricchii)

Doors and windows – Solid Afara- white (Terninalia superba), Apa (Afzelia africana), Black Afara(Terninalia ivorensis), Gedu Nohor (Entandrophragma angolense), Iroko(milecia excelsa), Lagos Mahogany (Khaya ivorensis), Mansonia(Mansonia altissima), Sapelewood (Entandrophragma cylindricum), Utile(Entandrophragma utile)

Flooring and decking Agba (Gossweilerodendron balsamiferum), Albizia (Albizia spp.), Danta(Nesogordonia), Iroko (milecia excelsa), Omu (Entandrophragmacandolei) (Opepe (Nauclea diderricchii), Sapelewood (Entandrophragmacylindricum)

Shingles and battens Abura (Mitragyna stipulosa), Black Afara (Terninalia ivorensis), GeduNohor (Entandrophragma angolense), Mangrove

(Rhizophora racemosa)

Sills and thresholds Dahoma (Piptadeniastrum africanum), Iroko (milecia excelsa), Opepe(Nauclea diderricchii)

Stair Treads Guarea (Guarea spp.), Mahogany (Khaya spp.), Sapelewood(Entandrophragma cylindricum)

(Entandrophragma cylindricum) Abura (Mitragyna stipulosa), Afara (Terminalia

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Roof rafters and purlins superba), Agba(Gossweilerodendron balsamiferum), Albizia (Albizia spp.), Danta(Nesogordonia papaverifera), Iroko (milecia excelsa), Obeche(Triplochiton scleroxylon), Opepe (Nauclea diderricchii), Sapelewood(Entandrophragma cylindricum)

Source: (Okigbo, 1964)

2.5 METALS

Recognition of metals is based on two headings, namely ferrous and non-ferrous metals.

Ferrous metals are produced from iron ore, cast iron, wrought iron and steel while ferrous metals

include aluminium, copper, zinc, bronze and brass. Metal sheets for roofing are quite effective

in warm, humid climates, for these materials can be at the same time reflective and impermeable.

They are also highly conductive, and they cool down as quickly as they heat up (Gut and

Ackerknecht 2005). In Nigeria, materials like zinc, aluminum and asbestos are commonly used

in form of sheets for roofing in modern building constructions, but these materials have a high

ability to conduct heat (solar radiation) into the interior space of a building, a situation that

causes discomfort in indoor space in dry season (Akpabio et al., 2001).

Aluminium is leading the way into the future of the construction industry. The great

growth in the use of aluminum metal indicates its versatility. It has a unique combination of

useful properties: lightness, good thermal and electrical conductivity, high reflectivity,

malleability, resistance to corrosion, and excellent tensile strength in alloyed form (Komolafe,

1988).

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2.6 PLASTICS

The term plastics cover a range of synthetic or semi-synthetic organic condensation or

polymerization products that can be molded. The two major types of plastic are thermoplastics

and thermosetting resins (thermosets). Plastics vary immensely in heat tolerance, hardness, and

resiliency.

2.7 GLASS

Glass is used in building mainly as flat glass and for products such as lences, glass fibres

and foamed (cellular) glass (Fadamiro and Ogunsemi, 1996). Glass has the following properties.

I. Appearance: Glass is transparent and more or less colourless.

II. Strength properties: Glass in building is required to resist loads including wind

loads, impact by persons and animals and sometimes thermal and other stresses.

III. Thermal insulation: Although glass is dense and is a good conductor of heat, its

surface resistance is high so that doubling the thickness almost halves the heat lost

through a single plane, the optimum gap being about 20mm.

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3.0 THERMAL PROPERTIES OF BUILDING MATERIALS IN NIGERIA

The basic properties that indicate the thermal behavior of building materials are:

absorptivity, density (p), specific heat (cm), and thermal conductivity (k).

Table 2: Thermal Properties of Building Material at Room Temperature

Material Thermal Conductivity(W/m degree K) @~300 K

Specific Heat(J/kg degree K)

Density(kg/m3)

Brick 0.7 840 1600Concrete – cast dense 1.4 840 2100Concrete – cast light 0.4 1000 1200Granite 1.7-3.9 820 2600Glass (window) 0.8 880 2700Hardwoods (oak) 0.16 1250 720Softwoods (pine) 0.12 1350 510Polyvinyl chloride 0.12-0.25 1250 1400Paper 0.04 1300 930Acoustic Tile 0.06 1340 290Particle board (low density)

0.08 1300 590

Particle board (high density)

0.17 1300 1000

Fiberglass 0.04 700 150Expanded polystyrene 0.03 1200 50

Source: (Incropera, 1990)

3.1 ABSORPTIVITY

Absorptivity is the property of a surface which determines what proportion of incident

radiation it absorbs. It is the property of a material which determines radiant exchange of a

surface with its environment. It is the main factor in determining the temperature response to

short-wave (solar) radiation, and is dependent largely by color.

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3.2 SPECIFIC HEAT

Specific heat of a substance is the amount of heat energy required to raise the temperature

of a unit mass of the substance by one degree Celsius. Specific heat describes a material's ability

to store heat energy. It is measured in J/kg degree C (ASHRAE, 2005).

3.3 THERMAL CONDUCTIVITY

Thermal conductivity of a material is the rate of heat flow through a unit area of unit

thickness of the material for a unit temperature difference across the material. It is also known as

the K-value and is measured in W/m degree C. Good insulators have lower thermal

conductivities (ASHRAE, 1977).Thermal conductivity as a material property will not differ with

the dimensions of the material, but it is dependent on the temperature, the density and the

moisture content of the material (CLEAR website). Generally light materials are better insulators

than heavy materials, because light materials often contain air enclosures. Dry still air has a very

low conductivity. A layer of air will not always be a good insulator though, because heat is easily

transferred by radiation and convection.

When a material, for instance insulating material, becomes wet, the air enclosures fill

with water and, because water is a better conductor than air, the conductivity of the material

increases. That is why it is very important to install insulation materials when they are dry and

take care that they remain dry.

The process of conduction and radiation often generate heat experience in interior spaces via the

roof and walls. The radiation transport is strongly dependent on temperature and particularly

significant at high temperatures. The convention can be negligible for small pore sizes (Akpabio

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et al., 2001). The temperature variation with thickness of a solid material determines if a material

is suitable as heat insulator or conductor. The actual heat transmission by conduction depends on

the bonding between molecules (Collieu and Powney, 1977).

3.3.1 CONDUCTANCE VS CONDUCTIVITY

Conductivity (k) is a material property and means its ability to conduct heat through its

internal structure. Conductance on the other hand is an object property and depends on both its

material and thickness. Conductance equals conductivity multiplied by thickness, in units of

W/m²K. As conductivity is the reciprocal of resistivity, the total resistance of a material can

therefore be given as its total thickness divided by total conductivity (CLEAR website).

Table 3: Building Materials And Their Thermal Conductivity For Dry (Indoor) And Wet (Outdoor) Conditions.

Group Material Specific mass (kg/m3)

Thermal conductivity (W/mK)Dry Wet

Metal Aluminium 2800 204 204Copper 9000 372 372Lead 12225 35 35Steel, Iron 7800 52 52Zinc 7200 110 110

Natural stone Basalt, Granite 3000 3.5 3.5Bluestone, Marble 2700 2.5 2.5Sandstone 2600 1.6 1.6

Masonry Brick 1600-1900 0.6-0.7 0.9-1.2Sand-lime brick 1900 0.9 1.4  1000-1400 0.5-0.7  

Concrete Gravel concrete 2300-2500 2.0 2.0Light concrete 1600-1900 0.7-0.9 1.2-1.4  1000-1300 0.35-0.5 0.5-0.8  300-700 0.12-0.23  Pumice powder concrete 1000-1400 0.35-0.5 0.5-0.95

  700-1000 0.23-0.35  Isolation concrete 300-700 0.12-0.23  

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Cellular concrete 1000-1300 0.35-0.5 0.7-1.2  400-700 0.17-0.23  Slag concrete 1600-1900 0.45-0.70 0.7-1.0  1000-1300 0.23-0.30 0.35-0.5

Inorganic Asbestos cement 1600-1900 0.35-0.7 0.9-1.2Gypsum board 800-1400 0.23-0.45  Gypsum cardboard 900 0.20  Glass 2500 0.8 0.8Foam glass 150 0.04  Rock wool 35-200 0.04  Tiles 2000 1.2 1.2

Plasters Cement 1900 0.9 1.5Lime 1600 0.7 0.8Gypsum 1300 0.5 0.8

Organic Cork (expanded) 100-200 0.04-0.0045  Linoleum 1200 0.17  Rubber 1200-1500 0.17-0.3  Fibre board 200-400 0.08-0.12 0.09-0.17

Wood Hardwood 800 0.17 0.23Softwood 550 0.14 0.17Plywood 700 0.17 0.23Hard-board 1000 0.3  Soft-board 300 0.08  Chipboard 500-1000 0.1-0.3  Wood chipboard 350-700 0.1-0.2  

Synthetics Polyester (GPV) 1200 0.17  Polyethene, Polypropene 930 0.17  

Polyvinyl chloride 1400 0.17  Synthetic foam

Polystyrene foam, exp. (PS) 10-40 0.035  

Ditto, extruded 30-40 0.03  Polyurethane foam (PUR) 30-150 0.025-0.035  

Phenol acid hard foam 25-200 0.035  

PVC-foam 20-50 0.035  Cavity isolation

Cavity wall isolation 20-100 0.05  

Bituminous materials

Asphalt 2100 0.7  Bitumen 1050 0.2  

Water Water 1000 0.58  Ice 900 2.2  Snow, fresh 80-200 0.1-0.2  Snow, old 200-800 0.5-1.8  

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Air Air 1.2 0.023  Soil Woodland soil 1450 0.8  

Clay with sand 1780 0.9  Damp sandy soil 1700 2.0  Soil (dry) 1600 0.3  

Floor covering Floor tiles 2000 1.5  Parquet 800 0.17-0.27  Nylon felt carpet 0.05    Carpet (with foam rubber) 0.09    

Cork 200 0.06-0.07  Wool 400 0.07  

Source: Comfortable Low Energy Architecture website

3.4 DIFFUSIVITY

Diffusivity is the measure of how fast heat travels through a material, and is a function of

the conductivity divided by the product of the density and specific heat (units: area/time). The

time lag between outside and inside peak temperatures is a function of the thickness of the

material divided by the square root of the diffusivity.

3.5 THERMAL DIFFUSIVITY

The principle of thermal diffusivity is to generate a signal on one face of a material and

examine the response on the other face (Meukam, P. 2004).

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Fig. 1: Thermal diffusivity measurement apparatus.

Source: (Meukam P., 2004)

Materials used in walls, floor and other sun-exposed parts of the house should have

adequate thermal storage or reflectance, that is, thermal properties able to respond to the needs of

the climate where the building is located. Hence, the principle of thermal mass.

3.6 THERMAL MASS

Thermal mass is a property that enables building materials to absorb, store, and later

release significant amounts of heat. Buildings constructed of concrete and masonry have a

unique energy-saving advantage because of their inherent thermal mass (EUSFHVEW, 2001).

These materials absorb energy slowly and hold it for much longer periods of time than do less

massive materials. This delays and reduces heat transfer through a thermal mass building

component, leading to the following results.

1. There are fewer spikes in the heating and cooling requirements, since mass slows the

response time and moderates indoor temperature fluctuations.

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2. A massive building uses less energy than a similar low mass building due to the reduced

heat transfer through the massive elements (EUSFHVEW, 2001).

The thermal mass of concrete has the following benefits and characteristics:

Delays peak loads

Reduces peak loads

Reduces total loads in many climates and locations

Works best in commercial building applications

Works well in residential applications

Works best when mass is exposed on the inside surface

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REFERENCES

Akpabio, L.E, Ekpe, S.D, Etuk, S.E, and Essien, K.E (2001): Thermal Properties of Oil and

Raffia Palm Fibrers, Global J.Pure Appl. Sci., 7(3): 575-578.

Alade, G.A. and Lucas, E.B. (1982): Timber connector: a major contributor to structural

failure in wooden components in Nigeria. Paper presented at the 36th annual

meeting of the Forest Products Research Society, mechanical fastening session,

New Orleans, U.S.A., June 24, 1982. 22 pp.

ASHRAE Handbook of Fundamentals, 1977.

ASHRAE Handbook of Fundamentals, 2005.

Comfortable Low Energy Architecture website:

(http://www.learn.londonmet.ac.uk/packages/clear/index.html )

Collieu, A.M.B and Powney, D.J (1977): The Mechanical and Thermal Properties of

Materials. London: Edward Arnold. p. 283.

Energy Use of Single-Family Houses with Various Exterior Walls, “EUSFHVEW” (2001).

Fullerton, R.L. (1979): “Building Construction In Warm Climates (vol. 1)” Oxford University

Press, London.

Goldstein, E.W. (1999): Timber construction for Architects and Builders. McGraw-Hill, New

York, USA.

Gut, P. and Dieter, A. (2005): Climate Responsive Building. St. Gallen, Switzerland:

24 SKAT [Swiss Centre for Development Cooperation in Technology and

Management].

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Incropera, F., De Witt, D. (1990): Introduction to Heat Transfer, 2nd Edition, John Wiley and

Sons

Keenan, F.J. and Tejada, M (1984) : Tropical Timber for Building Materials in the Andean

Group Countries of South America

Komolafe, L. K. (1988): "Influence of Climate on Building Design and Thermal Performance

Assessment of Some Construction Materials" in Ten Years of Building and Road

Research. Edited by G. N. Omange, NBRRI, Lagos. pp 95-108.

Lucas, E.B. and Olorunnisola, A.O. (2002): Wood processing and utilization in Nigeria: the

present situation and future prospects in: Ajav, E.A., Raji, A.O., and Ewemoje,

T.A. (Eds) Agricultural Engineering in Nigeria: 30 Years of University of Ibadan

Experience, Published by the Department of Agricultural Engineering, University

of Ibadan, Nigeria. pp. 98-109.

Meukam, P. (2004): Construction and Building Materials.

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