Bonding

Figure 1.12 illustrates the effects of bonding. The stretcher bond is standard for cavity walls and normally a half-lap bond is used, but an increase in horizontal emphasis can be achieved by the less standard quarter or third bond. In conservation work it may be necessary to use half bricks (snap headers) to match the appearance of bonding in solid brick walls. For one-brick-thick walls more variations are possible most typical are the English and Flemish bonds. The equivalent English and...

Clay Brickwork

The bonding, mortar colour and joint profile have a significant visual effect on brickwork. The overall effect can be to emphasise as a feature, or reduce to a minimum, the impact of the bonding mortar on the bricks. Additionally the use of polychromatic brickwork with complementary or contrasting colours for quoins, reveals, banding and even graphic designs can have a dramatic effect on the appearance of a building. The three-dimensional effects of decorative dentil courses and projecting...

Softwood Cladding

Western red cedar has long been the preferred timber for external timber cladding because of its durability and warm colour. However, recently the popularity of larch and Douglas fir as softwood cladding has increased as greater emphasis is placed on the use of renewable resources from sustainable forests. Large quantities of these materials, which are classified as moderately durable to decay, will become available as Fig. 4.16 Timber pole construction - Hooke Park, Dorset. Lodge (Edward...

Acknowledgements

I wish to acknowledge the assistance of my colleagues in the Leicester School of Architecture, Department of Product and Spatial Design, Faculty of Art and Design, De Montfort University, Leicester, for suggesting amendments and additions to the various chapters of this book for its third edition, especially Robert Sheen in the Resources Centre for sourcing considerable material. I wish to thank my wife, Susan, for her participation and support during the production of this work, also my...

Atmospheric Pollution

Stones based on calcium carbonate are particularly vulnerable to attack by acid atmospheric pollutants. Sulfur dioxide in the presence of water and oxygen from the air produces sulfuric acid which attacks calcium carbonate to produce calcium sulfate. Limestones and calcareous sandstones are vulnerable to attack. In the case of limestone, the gypsum (calcium sulfate) produced at the surface is slightly soluble and on exposed surfaces gradually washes away leaving the eroded limestone clean. In...

Structural Glass

Glass columns are frequently used as fins to restrain excessive deflection caused by wind and other lateral loads to glass facades. The fixings between the facade glazing and fin units are usually stainless steel clamps bolted through preformed holes in the toughened or laminated glass, although silicone ad-hesives can also be used. Typically storey-height fins are 200-300 mm wide in 12-15 mm toughened glass, fixed into aluminium or stainless steel shoes to the floor and or glazing head. A soft...

Insitu Concrete

The quality of in-situ visual concrete is heavily dependent upon the formwork as any defects will be mirrored in the concrete surface. The formwork must be strong enough to withstand, without distortion, the pressure of the fresh concrete, and the joints must be tight enough to prevent leakage, which can cause honeycombing of the surface. A wide range of timber products, metals and plastics are used as formwork, depending upon the surface finish required. The Independent Television News...

Calcium Silicate Brickwork

Most design considerations are the same for either clay or calcium silicate brick. However, calcium silicate bricks are particularly popular for their light reflecting properties, for example in light wells or atria. Their smooth crisp appearance with a non-abrasive surface is particularly appropriate for some interior finishes and also forms an appropriate base for painted finishes. The use of complementary coloured mortars enhances the aesthetic effect when using strongly coloured bricks....

Jointing methods

Aluminium components may be joined mechanically with aluminium bolts or rivets non-magnetic stainless steel bolts are also appropriate. If aluminium is to be electric-arc welded, the use of an inert-gas shield, usually argon, is necessary to prevent oxidation of the metal surface. A filler rod, compatible with the alloy Fig. 5.18 Aluminium discs - Selfridges Store Birmingham. Architects Foster and Partners. Photographs Arthur Lyons Fig. 5.18 Aluminium discs - Selfridges Store Birmingham....

Green roofs

Green roofs are flat or low pitched roofs which are landscaped over the waterproofing layer. The landscaping may include some hard surfaces and have access for leisure and recreational functions as well as the necessary routine maintenance. Green roofs offer not only increased life expectancy for the waterproofing layer by protecting it from physical damage, ultraviolet light and temperature extremes, but also increased usable space. Environmental advantages include reduced and delayed...

Acrylated Rubber Paints

Acrylated rubber paints are suitable for internal and external applications exposed to chemical attack or wet and humid atmospheric conditions. Acrylated rubber paints are tending to replace chlorinated rubber coatings which rely on carbon tetrachloride solvent, now considered environmentally damaging. Acrylated rubber paints may be applied to metal or masonry by either brushing or spraying. Usually a film of dry thickness 100 microns is applied compared to 25-30 microns for most standard paint...

Limestone Bauxite

Fig. 3.3 Manufacture of calcium aluminate (high alumina) cement Fig. 3.3 Manufacture of calcium aluminate (high alumina) cement the concrete, in which changes in the crystal structure, accelerated by high temperatures and humidity, have caused serious loss of strength, increased porosity and subsequent chemical attack. Depending upon the degree of conversion, calcium aluminate cement becomes friable and a deeper brown in colour the exact degree of conversion can only be determined by chemical...

Variety

Bricks may be described as common, facing or engineering. Common bricks have no visual finish, and are therefore usually used for general building work especially where the brickwork is to be rendered, plastered or will be unseen in the finished work. Facing bricks are manufactured and selected to give an attractive finish. The particular colour, which may be uniform or multicoloured, results from the blend of clay used, and the firing conditions. Additionally, the surface may be smooth,...

Glass supporting systems

The fixing of glazing, and particularly solar control glasses, should be sufficiently flexible to allow for tolerances and thermal movements. A minimum edge clearance of at least 3 mm is required for single glazing and 5 mm for double-glazing units. Edge cover should be sufficient to cope with the design wind loading, with a minimum normally equal to the glass or unit thickness to ensure a neat sight line. Glass thickness The Planar Assembly Fig. 7.19 Typical facade glazing system should be...

Recycling of plastics

The use of plastics within European countries is approximately 44 million tonnes per year, with products for the construction industry accounting for over a half of the consumption of PVC. Currently most waste disposal is within landfill sites. However, certain thermoplastic products can be recycled into construction products. Expanded polystyrene waste can be recycled by solvent extraction into a material, which has the appearance and many characteristics of wood. PVC bottles can be recycled...

Mortars

The mortar in brickwork is required to give a bearing for the bricks and to act as a sealant between them. Mortars should be weaker than the individual bricks, to ensure that any subsequent movement does not cause visible cracking of the bricks, although too weak a mix would adversely affect durability of the brickwork. Mortar mixes are based on blends of either cement lime sand, masonry cement sand or cement sand with plasticiser. When the mix is gauged by volume an allowance has to be made...

Recycling Fibrereinforced Polymers

Currently, the majority of waste fibre-reinforced polymers (FRPs) are disposed into landfill sites. One alternative is to grind the material into powder and use this ground GRP in conjunction with other binders however, this process is difficult where embedded metal fixings were incorporated into the original components. The recyclate powder can be blended with other recycled plastics to produce GRP plastics lumber, which can be used for lightly loaded piles, decking, fencing and similar...

Monocoque construction

The Lord's Cricket Ground Media Centre (Fig. 5.19) was the world's first semi-monocoque building in aluminium. The media centre is a streamlined pod raised 14 m off the ground on two concrete support towers, giving journalists and commentators an uninterrupted view over the cricket ground. The structure consists of a curved 6 and 12 mm aluminium-plate skin welded to a series of ribs. Thus acting together, the skin and the ribs provide both the shape and the structural stability, a system...

Extensive Green Roofs

Extensive green roofs are designed to be lighter in weight, relatively cheap, not open to recreational use and to require the minimum of maintenance. Their prime purpose is either ecological or for the environmental masking of buildings. Planting should be of drought-tolerant, wind- and frost-resistant species such as sedums, herbs and grasses. Instant cover can be created by the installation of pre-cultivated vegetation blankets where the immediate visual effect is required. Alternatively, a...

Intelligent glass facades

An intelligent glass building facade changes its physical properties in response to sensors detecting the external light and weather conditions, thus reducing the energy consumption necessary to maintain the appropriate internal environment. Therefore intelligent facades have ecological significance in reducing global greenhouse emissions and also in reducing operational building costs to clients and users. Truly intelligent facades capitalise on the incident solar energy striking the facade of...

Carbon Content Of Ferrous Metals

The quantity of carbon alloyed with iron has a profound influence on the physical properties of the metal due to its significant effect on the microscopic crystal structure (Fig. 5.8). At ambient temperature a series of crystal forms (ferrite, pearlite and cementite) associated with different proportions of iron and carbon are stable. However, on increasing the temperature, crystal forms that were stable under ambient conditions, become unstable and are recrystallised into the high temperature...

Deterioration Of Timber

The major agencies causing the deterioration of timber in construction are weathering, fungi, insects and fire. The natural durability of timber is defined into five categories in relation to the resistance of the heartwood to wood-decaying fungi (BS EN 350-1 1994). On prolonged exposure to sunlight, wind and rain, external timbers gradually lose their natural colours and turn grey. Sunlight and oxygen break down some of the cellulose and lignin into water-soluble materials which are then...

Intensive Green Roofs

Intensive green roofs are generally designed to accept recreational activity and to include the widest range of vegetation from grass to shrubs and semi-mature trees. Depths of soil are typically between 200 and 300 mm, which together with the necessary minimum 50 mm of water reservoir and drainage systems generate an additional imposed load of typically 400 kg m2 on the existing or proposed structural system. Intensive green roofs may incorporate both soft and hard landscaping and slopes up to...

Manufacture Of Steel

The production of steel involves a sequence of operations which are closely inter-related in order to ensure maximum efficiency of a highly energy-intensive process. The key stages in the production process are the making of pig iron, its conversion into steel, the casting of the molten steel and its formation into sections or strip. Finally, coils of steel strip are cold rolled into thin sections and profiled sheet. The raw materials for the production of iron are iron ore, coke and limestone....

Standards

BS 144 1997 Specification for coal tar creosote for wood preservation. BS 373 1957 Methods for testing small clear specimens of timber. BS 476 Fire tests on building materials and structures Parts 3, 4, 6, 7, 10-13, 15, 20-24, 31-33 BS 644 2003 Timber windows. Factory assembled windows of various types. BS 1088 Marine plywood Part 1 2003 Requirements. Part 2 2003 Determination of bonding quality. BS 1186 Timber for and workmanship in joinery Part 2 1988 Specification for workmanship. Part 3...

Building Research Establishment Publications

BRE Digest 309 1986 Estimating daylight in buildings Part 1. BRE Digest 310 1986 Estimating daylight in buildings Part 2. BRE Digest 338 1988 Insulation against external noise. BRE Digest 346 The assessment of wind loads. Part 1 1992 Background and method. Part 2 1989 Classification of structures. Part 3 1992 Wind climate in the United Kingdom. Part 4 1992 Terrain and building factors and gust peak factors. Part 5 1989 Assessment of wind speed over topography. Part 6 1989 Loading coefficients...

Chemical attack and aggressive ground

The resistance of cured concrete to acid attack is largely dependent upon the quality of the concrete, although the addition of granulated blastfurnace slag GGBS or fly ash pulverised-fuel ash PFA increases the resistance to acids. Limestone-aggregate concrete is more vulnerable to acid attack than concretes with other aggregates. The resistance of cured concrete to chemical attack is defined by the design chemical class number, ranging from DC1 low resistance to DC 4 high resistance . The...

BRE Digests

BRE Digest 293 1985 Improving the sound insulation of separating walls and floors. BRE Digest 294 1985 Fire risk from combustible cavity insulation. BRE Digest 295 1985 Stability under wind load of loose-laid external roof insulation boards. BRE Digest 324 1987 Flat roof design thermal insulation. BRE Digest 336 1989 Swimming pool roofs minimising the risk of condensation. BRE Digest 337 1988 Sound insulation basic principles. BRE Digest 338 1988 Insulation against external noise. BRE Digest...

Rammedearth and cob construction

Earth construction is one of the oldest forms of building used by mankind. Rammed-earth buildings can be found in most countries, and many have survived hundreds of years. The ideal material is a well-graded mixture of gravel, sand, silt and clay fines. The clay content should be sufficient to act as an efficient binder, but not in excess to cause large moisture movement or cracking of the finished construction. In modern rammed-earth construction Portland cement is frequently incorporated as a...