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Pitched roof structure
Published in Derek Worthing, Nigel Dann, Roger Heath, of Houses, 2021
Derek Worthing, Nigel Dann, Roger Heath
The primary function of a roof is to protect the building below from the weather – principally falling rain, but also wind itself, wind-driven rain, snow and mists. Building Regulations Approved Document Part C: Site Preparation and Resistance to Contaminates and Moisture is concerned with the avoidance of moisture transfer from sources external to the roof. It is also concerned with internally generated condensation, as will be discussed later. Part C impacts more on the roof coverings than the structure; however, the pitch of the roof structure is one of the principal means by which roofs resist the ingress of moisture. The majority of houses in this country are constructed with pitched roofs. Generally the steeper the pitch, the more potentially effective a roof will be at avoiding the ingress of rain or other forms of precipitation. Whilst the angle of the pitch may be dictated by aesthetic or structural factors, it may also be influenced by the nature of the roof covering. Modern tiles permit very shallow pitches but some of the older traditional coverings, such as handmade clay tiles, require quite steep slopes to ensure that rain does not penetrate the roof covering. Shallow pitches are generally cheaper to construct, with savings in both timber and tiling.
Building Construction Technology and Management
Published in P.K. Jayasree, K Balan, V Rani, Practical Civil Engineering, 2021
P.K. Jayasree, K Balan, V Rani
The roof is the top part of a building and is built to protect the building from rain, snow, hail, direct sunlight from the wind, etc. Depending on the form and the material used, there are different types of roof. A ceiling is an overhead inner surface covering a room’s upper limits. It is not usually regarded as a structural element but as a finished surface that hides the underside of the roof structure or the floor above. Ceilings can be tastefully decorated.
Efficient Building Operation
Published in Scott Offermann, Creating a Strategic Energy Reduction Plan, 2020
Maintenance considerations to reduce energy consumption begin with verifying that the roof is clear of debris and in good repair. This should be done on a regular basis. The roof should be visually checked for deterioration and signs of leaks and water penetration. Water penetration can cause insulation to lose effectiveness and can transfer heat more rapidly. Professional roofing contractors can assess the age, condition, signs of water penetration and can also determine R-value of a roofing system if the information is not easily available.
Seismic vulnerability and risk assessment at the urban scale using support vector machine and GIScience technology: a case study of the Lixia District in Jinan City, China
Published in Geomatics, Natural Hazards and Risk, 2023
Yaohui Liu, Xinyu Zhang, Wenyi Liu, Yu Lin, Fei Su, Jian Cui, Benyong Wei, Hao Cheng, Lutz Gross
The factors that may affect the seismic performance of buildings, such as the building structure, characteristics, quality, age, and preservation state, are considered. The building data required in this study include the type of structure, roof type, number of floors, period of construction, and preservation state (Riedel et al. 2014). According to the urban planning data from Lixia District and Jinan city, the building period was divided into four subperiods: 2002-present, 1982-2002, 1960-1981, and before 1960. According to the RISK-UE seismic assessment method, the number of floors was divided into three categories: low-rise buildings with two floors or less, moderate-rise buildings with three to five floors (including five floors), and high-rise buildings with more than six floors (Lestuzzi et al. 2016). The roof types were divided into two categories: flat roofs and sloped roofs. The effects of site factors and topography on seismic vulnerability were not considered in this study.
Using convolutional neural networks to identify illegal roofs from unmanned aerial vehicle images
Published in Architectural Engineering and Design Management, 2023
In Taiwan, illegal structures are structures that lack a legal construction or usage license. These structures include illegal farmhouses, container houses, prefabricated buildings, and steel sheds. Illegal buildings are defined as illegally built structures, such as metal-sheet factories, factories, and illegal markets. Illegal roofs are defined as illegal rooftop additions on buildings that comprise two or more stories, and they are the most common type of illegal structures in Taiwan and the subject of this study. Illegal buildings are predominantly reserved for factories and manufacturing plants. Illegal roofs are primarily used for waterproofing, heat insulation, storage, and housing. Figure 1 depicts the relationship between illegal structures, illegal buildings, and illegal roofs. Most of the illegal buildings and illegal roofs within the study area are gable roofs (A), shed roofs (B), and flat roofs (C), as shown in Figure 2. These roofs are mostly constructed using durable steel. The beams and columns are made of H-shaped steel, and the trusses are made of C-shaped steel. The roofs themselves are predominantly made of metal materials, such as magnesium–aluminum–zinc alloys, aluminum–zinc plating, zinc plating, and stainless-steel baking varnish. Table 1 shows the perspective view, plan view, cross-sectional view, and features of gable roofs, shed roofs, and flat roofs.
An evaluation of the retrofit net zero building performances: life cycle energy, emissions and cost
Published in Building Research & Information, 2023
Replacement costs (RCs) are the planned expenditures for major building assemblies and systems (e.g. roofing membrane). Different assemblies have a different service life that is independent from the whole building service life. For example, a roofing system service life is 20–25 years, and a complete replacement is normally needed afterward. If the whole building service life is 60 years, then the roof system needs to be replaced at least once within the 60-year building life span to maintain the required level of insulation and moisture control. RCs are discounted to their present value, prior to the addition of the LCC total, using Equation (1) (Fuller & Petersen, 1995): where d is the discount rate (interest rate), t is the year, and n represents a specific year when the present value is calculated. PV indicates the present value, and F is the future case amount occurring at the end of the year n (Marszal & Heiselberg, 2011). For instance, if the discount rate is 5%, then the present value of $78.35 at the end of the fifth year will be $100. For decision-makers, those two amounts are time equivalent. Therefore, they will not have a preference between $78.35 received today and $100 received at the end of five years. In this study, the replacement frequency for HVAC systems and the water supply system is once during a 40-year life span, window replacement is once per 20 years, and other building components are assumed not to be replaced, with a discount rate of 3%.