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...

Thermosetting Plastics Phenol formaldehyde

Phenol formaldehyde (PF) was the original, and remains the cheapest thermosetting resin. Currently, its main use is in the production of laminates by the hot pressing of layers of resin-impregnated paper, fabric or glass fibre. The cured resin is brown, but heat-resistant laminates for working surfaces and wallboards are laminated with a decorative printed paper film and coated with a clear melamine formaldehyde finish. Phenol formaldehyde is resistant to ignition, but produces a phenolic smell...

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...

Lead Sheet Cladding

For cladding, the thickness of lead to be used dictates the maximum spacing between vertical joints and the Fig. 5.25 Traditional lead roof. Contractor Norfolk Sheet Lead. Photograph Courtesy of Lead Contractors Association Fig. 5.25 Traditional lead roof. Contractor Norfolk Sheet Lead. Photograph Courtesy of Lead Contractors Association distance between laps. Vertical joints may be wood-cored rolls or welts and occasionally standing seams or hollow rolls, where the risk of physical damage from...

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...