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....

Building Research Establishment Publications

SD2 2002 Timber frame dwellings U-values and building regulations. BRE Digest 208 1988 Increasing the fire resistance of existing timber floors. BRE Digest 299 1993 Dry rot its recognition and control. BRE Digest 301 1985 Corrosion of metals by wood. BRE Digest 307 1992 Identifying damage by wood-boring insects. BRE Digest 327 1993 Insecticidal treatments against wood boring insects. BRE Digest 340 1989 Choosing wood adhesives. BRE Digest 345 1989 Wet rots recognition and control. BRE Digest...

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...

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...