There are various types of civil engineering materials used in roofing. Each type of civil engineering material has different functions when used in the construction process.
In building roofs, there are a variety of engineering material depending on the type and characteristics of the materials. Roofing material for cool houses also varies. For a cool house the following building material are used
Single-ply membrane (White)
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This refers to roofing membranes which are field applied with use of just one layer of membrane material (either composite or homogenous) instead of multiple layers. The materials’ thickness ranges from 1.1mm – 2mm. They may be homogenous or reinforced with glass fiber. Advantage of this material is that when combined with insulation and continuous support the form complete durable roof systems. They are quickly installed, they have the potential of prefabricating, easily repaired and also they have a very good service performance. This is the type of roofing material required for the project.
This refers to wood that has been prepared for building. In this case timber will be used to construct Fascias and Barge Rafters. Also, timber will be used in the installation of soffit, purlin, roof struts, roof hangers, wall plate, and ceiling joists. Timber is preferred because it has several advantages. Its weight is light and it offers both protective and decorative uses, it’s a cheap product, it’s a better thermal insulator, it’s readily available and the structures build of timber are easily repaired.
Metal. (Stainless steel)
Metals will be used for flashing at all the levels of the structure. This is for the protection of the intersection and joints from moisture intrusion. Joints to be protected include valleys, ridges and hips. Also, metal flashing will be used to protect openings in the roofs for skylights and chimneys and also for the protection of fascia intersection. In this case, stainless steel is the chosen metal because of its corrosion resistant, durability, its availability and its relative cheap price.
Structural frame – columns and beams
The size strength and materials of beams and columns are dictated by weight and the use of the building. In this case, reinforced concrete columns and beams will be used. Engineering materials used in this case include:
Aggregates are available in various sizes. They provide a very strong concrete. Fine aggregate is made of particles between 0.3 – 5 mm. Coarse aggregate have particles larger to up to 40mm.Gravel Aggregates are preferred because of their low radioactive background and there low cost. There fractions are as follows: 3 – 10 mm, 5 – 20 mm, 5 – 40 mm, 20 – 40 mm. These aggregates are obtained from gravel pits, lakes, riverbeds and riverbeds.
Portland cement will be the majorly used type of cement.
Steel to be used for reinforcement is usually provided as individual steel bars or those welded together into a mesh. The bars are utilized in the construction of beams and columns.
The beams and columns will be doubly reinforced with steel. This is because steel is corrosion resistant and also it is readily available.
When mixing these materials, good quality water is required. Drinking water is recommended in this process. However, water fetched from rivers and lakes usually has a normal quality. Salty must never be used in this mixing of the concrete. Apart from the mixing process, water is used in the curing process.
This granular material made of fine mineral particles. It comprises of granules of diameter between 0.0625 – 2 millimeters. It its divided into five sub-groups basing on size.
Very fine sand (0.625-0.125)
Fine sand (0.125 – 0.75mm)
Medium sand (0.25 – 0.5mm)
Coarse sand (0.5 – 1mm)
Very coarse sand (1mm – 2mm)
Green roofs are known to be environmentally friendly. Some of the advantages of green roofs include: reduction of storm water runoff as part of sustainable development, Reduction of energy use, Climate change mitigation, climate change adaptation and lessening of he urban heat island effect To continue with environmental friendly construction, green roofs should be incorporated into the design. The design of the roof should consist of a gradient of 30 to 100. The minimum fall should be 1:6. This encourages drainage. The roof should be designed such that it is waterproof and there is no leakage. This is ensured by choosing a good, durable water proof roofing material. Waterproof installation with its detailing perimeters, outlets and protrusions through the roof must be taken into account the depth of the green roof build. The water proofing is one hundred and fifty millimeters above the substrate level at interval up-stands and protrusions, and at least one hundred millimeters at external perimeters. Up-stands, roof perimeters, outlets and protrusions through the roof is protected by an un-vegetated barrier such as 20-40mm rounded shingle or concrete paving slabs. This is the same depth as the substrate and not less than 500mm across. The water proof layer is designed in such a way that it is 150 mm above other elements
Insulation of the building controls the flow of heat in a building. It slows the rate of heat flows into a building in summer or out in winter. This not only saves the environment but also saves on heating costs as well as cooling costs. To achieve this, some modifications have to be included in the selection of the material to be used for construction and the design of the building. The external walls and ceilings are insulated to facilitate the saving of heating and cooling costs. To facilitate this, double bricks are used on the walls to facilitate drawing the relatively steady temperature of the ground. Design of the windows should be the ones with energy efficiency this saves a larger percentage of energy conserving the environment. This is by featuring non-reactive gas in a vacuum closed gap, soft coatings, tepid edge spacers and other effective frame technology. To take advantage of the suns heat and light, the house orientation is designed such that the windows are facing south i.e. south facing windows. Also, a double framed wall saves energy. In our building, this will be achieved by designing to construct walls with offset vertical framing. This framing will eliminate thermal bridging.