Construction Technology - Essay Example

? Construction Technology Q d. Cold roof There is a design of the cold roof that has an attic space that is not ventilated. In this kind of design, the placing of the cold roof insulation is done in the same way as the one with ventilation and the ceiling of sealed completely so that it can be in a position of preventing any air from entering into the attic gap. A polypropylene membrane that is breathable is then used as the roof underlay. This is important as is enhances the diffusion of the moist air that is inside through it, while keeping the moisture outside from getting inside. There are no ventilations and the air in the gaps leave via the breather membrane (Lstiburek, and Carmody, 2004). The condensation’s risk is low with the roofs that do not have ventilations. If there exist any water pipes that go through the gap, then there might be a chance that they will freeze over. This is a problem that can be dealt with by insulating the pipes. Aside from the prevention of the ice dams, we find that the cold roofing is the best for the maintenance of the ceiling insulation of the building in a good condition. If the attic space is ventilated in a proper manner and the moisture inside is eliminated, a cold roof will greatly decrease the winter humidity that is within the building. If the weather becomes warm, we find that a cold roof will be important in making the building remain cool. With a cold roof, the temperature of the roof remains the same as that of the outside air. The cold roof helps in the prevention of the formation of the ice dams. These ice dams can always be a constant problem with the warm roofs. The formation of the ice dams is as a result of the melting of the snow on the roof and consequent freezing on the overhang (Lstiburek, and Carmody, 2004). Nevertheless, as there is melting of more snow, the ice dams catches water, which results to the seeping of moisture to the building through the roof, and this can always bring about structural damage. As the snow does not melt in the cold roof, there is nothing like the formation of ide dams and any other thing associated with it. Figure: Ductwork interior to thermal and pressure boundary The construction of the conventional cold roof involves an attic space that is well ventilated, and with a roof that is pitched. There is horizontal placing of insulation between the floor’s ceiling below and the attic joists. Any breaks or even spaces in the ceiling are sealed completely for the purposes of keeping the moist air out from the building. Then there is also the fitting of the roof rafters with an underlay of bitumen roof that air and moisture cannot get through. Ventilation is put in the gap between the insulation and the pitched rafters. The warm air that is inside moves up and escapes via the ventilations and the gag inside is filled up with the cold air outside. As a result, then temperature that is between the inside and the outside becomes equal, and there is some danger of condensation in these kinds of cold roofs. Interstitial is a major problem that occurs in the cold deck roofs in which the insulation is put between the joists that are found in the space above the ceiling. The insulation’s position implies that the roof deck together with a bigger part of its structure do not have adequate protection from the low temperatures that occur during the periods of winter (Lstiburek, and Carmody, 2004). These features than become quite older as compared to the building’s interior, and the air that has penetrated into the room below then condenses on the structure of the timber probable resulting to decay. When doing new work, the cold deck roofs are not the best and have in fact been banned in some countries such as Scotland. Q e. Suitable floor construction Simple spread footings The initial 900 to 1,200 clay layer can easily be moved as a result of shrinkage and expansion, and this depends on the amount of moisture available. Therefore, it is generally essential for the foundations to be excavated to a depth whereby the amount of moisture available stays stable. According to the British Standard 8004, the best minimum depth for foundations is 1m. But if the area has some trees around, depths of up to three meters is recommended. In the clay soil type, before the concretion of the foundations, it is important to ensure that the trench is protected from the heave by using a comprehensive layer to line it. This is actually the most ideal type of foundation with the crawlspace or basement construction for a clay type of soil. For majority of the soils that have fine grains such as clay it is appropriate to use the simple spread footings. This mainly depends on the load’s magnitude or intensity (Lstiburek, and Carmody, 2004). The foundation’s location in relation to the type of the soil should be aware of the hydrostatic pressure and the foundation walls since there is moisture in the soil. Alternative methods are usually used in the foundation if the structure loads of the soil are very heavy and the soil is poor, however, in the clay soil type, this is the best method because the soil is very fine and the structure loads not heavy. The method is also chosen because it is economical as compared to the alternative methods of foundation construction. There are some single spot square pads at the columns where the bearing walls have a form of elongation. They are nearly always reinforced. The load is delivered to the supporting soils directly by these footings. This type of foundation construction is also preferred because it is the most appropriate in the construction of houses that do not go beyond four stories. More so, it requires firm or strong soil conditions like clay type as they are in a position to support the construction on the spread footings area. This design is a very simple one as it offers adequate footing area for the distribution of the structure’s weight onto the soil. Characteristically, a 4.5” wide x 9” concrete footing is used. In addition, the footing’s width distributes the live and dead structure’s load on the soil, which allows an archetypal 8” wide concrete wall that is to be put on the footing. Moreover, the poured footing enables the provision of a surface that is level for the walls of concrete foundation (Lstiburek, and Carmody, 2004). The footings’ thickness will actually vary in accordance with the unleveled conditions of the soil. It should also be taken into consideration by the designer that even if the soil bearing is satisfied with a 12” wide footing, the crew of the foundation might require at least 16” so that they can have enough area for setting the wall forms on those footings as well as allowing for adjustments to be done on the errors in the dimension. An ideal spread footing foundation is usually also called the T wall.   As the building’s weight increases against the capacity of the bearing or the good bearing soil’s depth, the footings should be expanded in size or even some different systems should be used. Q f. The first floor of the house is usually the most vital part of the whole house. This is due to the fact that majority of the systems of support that is created for the house are situates in this section. Different from that, the floor is constructed in a different manner as it serves as the separation between flats as well as taking up most of the weight of the house. One has to know the parts of the first floor and the way they are built. The most critical part in the construction of the first floor of a building is the laying out a proper foundation for the house (Lstiburek, and Carmody, 2004). Nonetheless, the foundation of a house is the keystone of the whole house that is going to be constructed. This has the implication that when the foundation is damaged or removed, the house will not be in a position of standing on its own. It acts as the major framing’s leverage of the first floor of the building. Without this, it will not be possible for the frame to remain standing for a long period of time. Therefore, the need to always build the frame might be required when there is no optimum construction of the foundation. The material that is most commonly used in the construction of the first floor is concrete. It can either be put into forms that form the walls or even the use of concrete blocks. It can be used together with some other frames by just creating the spaces where the major joints will be fitted. The major joints will act as the frames’ main attachment to the foundation. There are various kinds of joints that can be used constructions (Lstiburek, and Carmody, 2004). For the building’s first floor, it is advisable and important that complex joints are used. This is purposely for making sure that the foundation, together with the frames is able to maintain their ground for some long periods. Some other materials that can be used in the construction of the first floor and also in the attachment of the frame to the base or foundation are screws, cement, nuts and duty glue. The kind of material is used in the construction or the laying of the first floor depends on the kind of building that is being constructed. The budged that goes into the laying of the first floor is also another important factor that should be taken into consideration when buying the materials, but for the frames, the main material that is used in the construction of this section. However, some other materials like aluminum and steel can also be used. Q g. The retail buildings are usually of five kinds namely the down-town shopping centers, distribution centers that are warehouse-type, supermarkets that are single storey, and mixed use residential or commercial and retail buildings whereby the retail units take up the sections of the superstores and ground floor. Nonetheless, we find that the retail sector appears to be very competitive and hence the steel building attributes in delivering solutions that are flexible and lightweight fast and cheaply makes steel to be the best and most preferred material of construction in this sector. The experience of consumer is vital in the retail construction. Using steel in the building, the plans of the retail floors are maximized, which gives the retailers the highest and best scope for configuring the layouts of the store to make the most sales to the targeted clients. Most retailers, especially the supermarkets are occupied by owners and thus, different from the other commercial sectors, are greatly interested in the cost of whole life and added value by having a sustainable design. As a consequence, this retail sector takes the lead in the consumption of low carbon constructions that are sustainable. The large retailers also do the procurement of large centers of distribution and majority of supermarket stores do diversification and hence purchase mixed-use constructions that for the reasons of planning usually consist of several upper floors of use for residential purposes. Floor systems In the retail construction, composite floor slabs are the most commonly used and are usually between 150mm to 180mm deep and a span of between 3m and 4m between the secondary beams. Their advantage is that their capacity of load is quite high and is able to achieve up to two hours of resistance to fire (Lstiburek, and Carmody, 2004). An imperative practical requirement is the hanging of services from that are from the steel decking together with the fact that the re-entrant shape is always considered the best for this reason whereby the heavy services as well as the lighting are backed from the slab. Slimdek is considered the best in the construction in the sector of mixed-use building and multi-storey retail particularly if the height of the building is controlled for the purposes of planning, and thus the least depth of the structure is critical to the construction’s success. It is also used in the basement car parking so that it can help in the minimization of the costs of sub-structure. Figure: The 4D’s of water-tightness The wall underlay either is an inflexible wall underlay; that is fibre cement or playwood, or a flexible wall underlay; that is a synthetic or paper-based. The wall underlays are installed in a direct manner over the framing. Then the cavity battens are also installed in a direct manner over the wall underlay. There are no more wall underlay that is required between the cavity battens and the wall cladding save for the situations that include the following: The metal cladding requires a layer of separation between the cavity battens and cladding that contain the treatment that is copper based. On a backing that is not rigid, the stucco requires a wall underlay that is flexible just like the backing that is not rigid. The wall underlay should be fitted according to the instructions or the required guidelines for the purpose of making sure that the water is led to the cavity’s bottom. It is very important to fit the wall underlay as it will help in the formation of a second line of protection to the framing from air or moisture. Reference Lstiburek, J.W. and J. Carmody, 2004, Moisture Control Handbook, ISBN 0-471-31863-9, John Wiley & Sons, Inc., New York, NY. Read More