一、概述1.基本特點以冷彎薄壁型鋼構件為基本結構骨架，以新型結構板材為結構體系，配以其它保溫、裝飾材料，經工廠集成生產和現場裝配而成的房屋建筑體系。

　　1、 Overview 1. Basic characteristics: A building system composed of cold-formed thin-walled steel components as the basic structural framework, new structural plates as the structural system, and other insulation and decorative materials, integrated in the factory and assembled on site.

　　該系統采用冷彎薄壁型鋼結構體系，具有截面尺寸小、自重輕等特點，比傳統建筑的使用面積提高5～10%，顯著地降低了基礎造價；獨特的墻體承重體系，使建筑造型富于輕靈動感，提高了室內布局的靈活性；低碳環保型建筑材料，使建筑耐久性更好、結構更安全，具有良好的抗震、防火、熱工、隔聲性能，是一種高效節能型綠色建筑體系。

　　The system adopts a cold-formed thin-walled steel structure system, which has the characteristics of small cross-sectional size and light self weight. It increases the usable area by 5-10% compared to traditional buildings and significantly reduces the foundation cost; The unique load-bearing system of the walls gives the building a light and dynamic appearance, enhancing the flexibility of indoor layout; Low carbon and environmentally friendly building materials make buildings more durable, structurally safer, and have good seismic, fire, thermal, and sound insulation properties. They are an efficient and energy-saving green building system.

　　2.適用范圍超輕鋼住宅體系適用于1～6層（不含地下室，檐口高度應不大于12m）的新建、改建、擴建建筑。但是冷彎薄壁型鋼骨架與鋼結構、鋼筋混凝土結構的混合結構建筑物的層數不受此限。

　　2. Scope of application: The ultra light steel residential system is suitable for newly built, renovated, and expanded buildings with 1 to 6 floors (excluding basements, with eaves height not exceeding 12m). However, the number of floors in mixed structure buildings with cold-formed thin-walled steel frames, steel structures, and reinforced concrete structures is not limited by this.

　　二、性能指標耐久性能：70年以上的使用年限；耐雪性能：1.55kN/㎡的基本雪壓；抗震性能：9度設防（基本地震加速度0.4g）；抗風性能：0.85kN/㎡的基本風壓，209km/hr的風速隔音性能：外墻隔音（200mm厚墻體）的隔聲量為65dB，內墻（雙面雙層9.5mm石膏板，181mm墻體）隔聲量為44dB；通風性能：自然通風和送風相結合，保證室內空氣清新潔凈，新風量大于15％；外墻抗沖擊性能：250kg的集中沖擊荷載；保溫隔熱性能：200mm厚墻體的熱阻值為4.24K?㎡/W，其保溫隔熱性能是490mm厚多孔砌塊磚的2倍。

　　2、 Performance indicator durability: a service life of over 70 years; Snow resistance performance: basic snow pressure of 1.55kN/m2; Seismic performance: 9-degree fortification (basic seismic acceleration 0.4g); Wind resistance performance: basic wind pressure of 0.85kN/m2, wind speed of 209km/hr Sound insulation performance: the sound insulation of the exterior wall (200mm thick wall) is 65dB, and the sound insulation of the interior wall (double-sided double-layer 9.5mm gypsum board, 181mm wall) is 44dB; ventilation performance: a combination of natural ventilation and air supply to ensure fresh and clean indoor air, with a fresh air volume greater than 15%; External wall impact resistance performance: concentrated impact load of 250kg; Thermal insulation performance: The thermal resistance value of a 200mm thick wall is 4.24K? ㎡/W, and its thermal insulation performance is twice that of a 490mm thick porous block brick.

　　三、規范性引用文件主要引用下列標準條文，當標準被修訂后，使用最新版本的引用標準：《建筑結構荷載規范》GB50009-2012《混凝土結構設計規范》GB50010-2010《建筑抗震設計規范》GBSOOll-2010《建筑設計防火規范》GB50016-2014《鋼結構設計規范》GB50017-2003《冷彎薄壁型鋼結構設計規范》GB50018-2002《建筑結構可靠度設計統一標準》GB50068-2001《低層冷彎薄壁型鋼房屋建筑技術規程》JGJ227-2011《水泥纖維平板》JC/T412.1-2006《纖維增強硅酸鈣板》JC/T564.1-2008《鋼結構工程施工質量驗收規范》GB50205-2001《碳素結構鋼》GB/T700-2006《冷彎型鋼技術條件》GB6725-2008《低合金高強度結構鋼》GB/T1591-2008《鋼結構工程質量檢驗評定標準》GB50221-2001其它國家或行業現行相關專業技術規范、規程。

　　3、 Normative reference documents mainly refer to the following standard provisions. When the standard is revised, the latest version of the reference standard is used: "Code for Load of Building Structures" GB50009-2012 "Code for Design of Concrete Structures" GB50010-2010 "Code for Seismic Design of Buildings" GBSOOll-2010 "Code for Fire Protection Design of Buildings" GB50016-2014 "Code for Design of Steel Structures" GB50017-2003 "Code for Design of Cold formed Thin walled Steel Structures" GB50018-2002 "Unified Standard for Reliability Design of Building Structures" GB50068-2001 "Technical Specification for Low rise Cold formed Thin walled Steel Buildings" JGJ227-2011 "Cement Fiber Plate" JC/T4121-2006 "Fiber Reinforced Calcium Silicate Board" JC/T564.1-2008 "Construction Quality of Steel Structure Engineering Acceptance Specification" GB50205-2001 "Carbon Structural Steel" GB/T700-2006 "Technical Conditions for Cold Formed Steel" GB6725-2008《 Low alloy high-strength structural steel "GB/T1591-2008" Quality inspection and evaluation standards for steel structure engineering "GB50221-2001 Other relevant professional technical specifications and regulations currently in use in other countries or industries.

　　四、 輕鋼住宅體系七大優勢1.安全

　　4、 Seven advantages of light steel residential system: 1. Safety

　　與木結構建筑相比，鋼結構建筑防火性能和防白蟻性能大大優于木結構建筑。超輕鋼結構形式建筑在北美的出現和發展很大原因是因為木結構自身的防火性能和防白蟻性能較差，因此在輕型木結構基礎上發展了超輕鋼結構體系。

　　Compared with wooden structures, steel structures have significantly better fire and termite resistance. The emergence and development of ultra light steel structure buildings in North America are largely due to the poor fire and termite resistance of wooden structures. Therefore, ultra light steel structure systems have been developed on the basis of lightweight wooden structures.

　　與傳統磚混結構相比，鋼結構體系本身較磚混結構更具延展性和彈性。超輕鋼結構屬于板肋結構體系，它由輕鋼龍骨和歐松板形成的墻體、樓板作為承重結構，屬于超靜定結構體系，單根輕鋼龍骨或歐松板的破壞不會立即導致整體結構的破壞，有利于建筑物內人員逃生。同時自重輕的鋼結構建筑更有利于抵抗地震時的水平荷載（水平荷載為建筑物自重和水平加速度的乘積，質量越小的建筑物承受的水平荷載越小）。所以在地震多發區域的日本和臺灣，低層建筑多為自重較輕的輕型木結構和鋼結構建筑。

　　Compared with traditional brick and concrete structures, steel structure systems themselves have more ductility and elasticity than brick and concrete structures. Ultra light steel structure belongs to the plate rib structure system, which is composed of walls and floors formed by light steel keel and European pine board as load-bearing structures. It belongs to the ultra static structural system, and the damage of a single light steel keel or European pine board will not immediately cause the overall structure to be destroyed, which is conducive to the escape of personnel inside the building. Steel structure buildings with light self weight are more conducive to resisting horizontal loads during earthquakes (horizontal loads are the product of the building's self weight and horizontal acceleration, with smaller buildings bearing smaller horizontal loads). So in earthquake prone areas such as Japan and Taiwan, low rise buildings are mostly lightweight wooden and steel structures.

　　2.方便與傳統磚混結構相比，自重輕的鋼結構建筑的運輸量小于磚混結構。利于在運輸不便的區域如島嶼、山區建造。超輕鋼建筑還可以根據項目需要在工廠完成部分拼裝任務，形成整片墻體和樓板，減少現場作業量，加快現場安裝速度，適用于當地施工條件惡劣，施工周期較短的項目。

　　2. Compared with traditional brick and concrete structures, the transportation volume of lightweight steel structure buildings is smaller than that of brick and concrete structures. Beneficial for construction in areas with inconvenient transportation, such as islands and mountainous regions. Ultra light steel buildings can also complete partial assembly tasks in the factory according to project needs, forming whole walls and floors, reducing on-site workload, accelerating on-site installation speed, and suitable for projects with harsh local construction conditions and short construction periods.

　　3.環保

　　3. Environmental Protection

　　輕鋼住宅體系產品所采用的建筑材料均為符合國家標準的綠色環保材料，所用輕鋼龍骨70年后仍可回收利用，現場建造過程中大量使用成品構件安裝，建造用水需求量小，整個建造過程比磚混結構大大減少廢水、廢塵和固體廢棄物的排放，有利于當地環境的保護。輕鋼住宅體系建造過程中材料損耗減少60%，現場垃圾減少80%，可回收材料占80%，建筑節能提高50%。

　　The building materials used in the light steel residential system products are all green and environmentally friendly materials that meet national standards. The light steel keel used can still be recycled after 70 years. During the on-site construction process, a large number of finished components are used for installation, and the construction water demand is small. The entire construction process greatly reduces the discharge of wastewater, dust, and solid waste compared to brick and concrete structures, which is conducive to the protection of the local environment. During the construction process of the light steel residential system, material loss is reduced by 60%, on-site waste is reduced by 80%, recyclable materials account for 80%, and building energy efficiency is increased by 50%.

　　4.節能輕鋼住宅體系外墻采用雙層保溫結構，由內向外分別為：石膏板、輕鋼龍骨、R19離心玻璃纖維棉、OSB（歐松板）、呼吸紙、擠塑板和外墻飾面層。由于墻體采用R19離心玻璃纖維棉和25mm厚擠塑板雙層保溫材料，墻體系統的熱阻值可達到為4.24K?㎡/W，其保溫隔熱性能是490mm厚多孔砌塊磚墻體的2倍。建筑屋蓋由內向外分別為：石膏板、R30離心玻璃纖維棉、輕鋼龍骨、OSB（歐松板）、防水卷材和屋面裝飾層。封檐板為多孔構造，使整個屋架通風透氣，流通的空氣既可防霉也可起到保溫隔熱的作用，整個屋蓋系統熱阻值為5.284K?㎡/W，是普通120mm厚混凝土屋頂（熱阻值為0.07K?㎡/W ）的75倍。

　　4. The exterior wall of the energy-saving light steel residential system adopts a double-layer insulation structure, which consists of gypsum board, light steel keel, R19 centrifugal glass fiber cotton, OSB (European pine board), breathing paper, extruded board, and exterior wall decorative layer from inside to outside. Due to the use of R19 centrifugal glass fiber cotton and 25mm thick extruded polystyrene board double-layer insulation material in the wall system, the thermal resistance value of the wall system can reach 4.24K? ㎡/W, and its insulation performance is twice that of 490mm thick porous brick walls. The building roof is composed of gypsum board, R30 centrifugal glass fiber cotton, light steel keel, OSB (European pine board), waterproofing membrane, and roof decoration layer from inside to outside. The eaves panel is a porous structure that allows the entire roof truss to be ventilated and breathable. The circulating air can not only prevent mold but also provide insulation. The thermal resistance value of the entire roof system is 5.284K? ㎡/W, which is 75 times that of a regular 120mm thick concrete roof (with a thermal resistance value of 0.07K? ㎡/W).

　　5.實用

　　5. Practical

　　輕鋼住宅體系雙層保溫裝飾外墻厚度僅為180mm，比一般不含保溫裝飾的磚混結構墻體（一般為240mm）還要小60mm.

　　The thickness of the double-layer insulation decoration exterior wall of the light steel residential system is only 180mm, which is 60mm smaller than the general brick and concrete structure wall without insulation decoration (usually 240mm)

　　根據所做項目測算，輕鋼住宅體系的得房率比普通磚混結構要提高5%-10%。同時由于輕鋼結構體系采用墻板和樓板受力而非傳統的梁柱受力，所以輕鋼建筑室內幾乎無梁無柱，空間利用更高。

　　According to the project calculations, the yield of light steel residential systems is 5% -10% higher than that of ordinary brick and concrete structures. At the same time, due to the use of wall panels and floor slabs instead of traditional beam column loads in the light steel structure system, there are almost no beams or columns in the interior of light steel buildings, resulting in higher space utilization.

　　6.快捷

　　6. Quick and efficient

　　輕鋼住宅體系采用工廠加工構件，現場拼裝，無需養護，所以施工速度比普通磚混結構要提高30%-50%。整個施工流程分：基礎施工、墻體安裝、屋頂安裝、結構封板、外墻保溫、室內裝飾、室外裝飾和完工交房八大步驟。不含基礎施工的毛坯房施工周期為1-2個月，精裝修房施工周期為2-3個月。一套100平方米的超輕鋼主體結構安裝時間只需4-5天，整體施工周期比傳統建筑至少縮減1/2的時間。

　　The light steel residential system adopts factory processed components, on-site assembly, and does not require maintenance, so the construction speed is 30% -50% faster than ordinary brick and concrete structures. The entire construction process is divided into eight steps: foundation construction, wall installation, roof installation, structural sealing, external wall insulation, indoor decoration, outdoor decoration, and completion and handover. The construction period for rough houses without foundation construction is 1-2 months, and the construction period for fine decoration houses is 2-3 months. A 100 square meter ultra light steel main structure can be installed in just 4-5 days, reducing the overall construction period by at least half compared to traditional buildings.

　　7.綜合經濟效益好

　　7. Good comprehensive economic benefits

　　A.施工周期短，早投產早得益；B.有效使用面積增加；C.投資使用分配合理，價符其值；地上與地下工程費分配90:10；D.材料與人工費分配?60:40；因此輕鋼住宅體系綜合經濟效益優于鋼筋混凝土結構。

　　A. Short construction period, early production and benefits; B. Increase in effective usage area; C. Reasonable allocation of investment use and value matching; Distribution of above ground and underground engineering costs 90:10; D. What is the allocation of material and labor costs? 60:40； Therefore, the comprehensive economic benefits of light steel residential systems are superior to those of reinforced concrete structures.

　　六、超輕鋼主體結構性能1.鋼材的選用用于低層冷彎薄壁型鋼房屋承重結構的冷彎薄壁型鋼, 應采用現行國家標準《碳素結構鋼》GB/T700、《低合金高強度結構鋼》GB/T1591 規定的Q235、Q345 ，以及滿足現行國家標準《連續熱鍍鋅鋼板及鋼帶》GB/T 2518、《連續熱鍍鋁鋅合金鍍層鋼板及鋼帶》GB/T14978 要求的Q550 級鋼材。

　　6、 Performance of Ultra Light Steel Main Structure 1. Selection of Steel: Cold formed thin-walled steel used for load-bearing structures of low rise cold-formed thin-walled steel buildings should use Q235 and Q345 specified in the current national standards "Carbon Structural Steel" GB/T700 and "Low alloy High strength Structural Steel" GB/T1591, as well as Q550 grade steel that meets the requirements of the current national standards "Continuous Hot dip Galvanized Steel Plate and Strip" GB/T 2518 and "Continuous Hot dip Aluminum Zinc Alloy Coated Steel Plate and Strip" GB/T14978.

　　2.結構性能冷彎薄壁型鋼鋼材強度設計值應按下表采用。冷彎薄壁型鋼材強度設計值（N/mm?）鋼材牌號鋼材厚度t（mm）屈服強度fy抗拉、抗壓和抗彎f抗剪fv端面承壓（磨平頂緊）feQ235鋼t≤6.0235205120310Q345鋼t≤6.0345300175400Q550鋼t≤0.6585500285—0.6＜t≤0.95504702700.9＜t≤1.25154402501.2＜t≤1.54654002303.鍍鋅量要求最小鍍層要求是保護鋼材不被腐蝕，對鍍鋅層厚度的使用按設計的要求進行。常用鍍鋅量要求如表下表所示。最小鍍鋅量要求（g/㎡）地區類別鍍鋅量最低要求一般地區180沿海地區、高腐蝕性地區275

　　2. The strength design values of cold-formed thin-walled steel for structural performance should be adopted according to the following table. Design value of strength for cold-formed thin-walled steel (N/mm?) Steel grade Steel thickness t (mm) Yield strength fy Tensile, compressive, and bending strength f Shear strength fv End face compression (ground flat and tightened) feQ235 steel t ≤ 6.0235205120310Q345 steel t ≤ 6.0345300175400Q550 steel t≤0.6585500285—0.6＜t≤0.95504702700.9＜t≤1.25154402501.2＜t≤1.54654002303. The minimum requirement for galvanized coating is to protect the steel from corrosion, and the thickness of the galvanized layer should be used according to the design requirements. The commonly used galvanizing requirements are shown in the table below. Minimum requirement for galvanizing amount (g/㎡) Regional category Minimum requirement for galvanizing amount General area 180 Coastal area, high corrosive area 275

　　4.鋼材的耐腐蝕性能根據建筑物建造地點環境不同，型鋼鍍鋅量要求也不同。鋅層多少決定房屋構造使用壽命。目前，各國標準基本分三擋：1）構件地處潮濕環境且裸露狀態時，鍍鋅量要求275克/m? (相當鍍鋅厚度為20微米);2 ）承重及外墻構件，鍍鋅量要求180克/m? (相當鍍鋅厚度為13微米);3 ）非承重構件, 鍍鋅量要求120克/m?(相當鍍鋅厚度為8微米);

　　4. The corrosion resistance of steel varies depending on the environment of the building construction site, and the requirements for the amount of galvanizing on the steel section also differ. The amount of zinc layer determines the service life of the building structure. At present, the standards of various countries are basically divided into three levels: 1) When the component is located in a humid environment and exposed, the required amount of galvanizing is 275 grams/m ? (equivalent to a galvanizing thickness of 20 microns); 2) The load-bearing and exterior wall components require a galvanizing amount of 180 grams/m ? (equivalent to a galvanizing thickness of 13 microns); 3) Non load bearing components require a galvanizing amount of 120 grams/m ? (equivalent to a galvanizing thickness of 8 microns);

　　根據英國鋼鐵公司對不同地區、環境的15棟輕鋼住宅跟蹤取樣測試結果是：輕鋼鍍鋅構件銹蝕率為三年平均不到0.1微米，也就是說，8微米厚鍍鋅冷彎薄壁型鋼構件，正常使用條件下，使用壽命可達240年。而一般住宅設計壽命僅60年；

　　According to the tracking sampling test results of 15 light steel residential buildings in different regions and environments by British Steel Company, the corrosion rate of galvanized components of light steel is less than 0.1 microns on average over three years. In other words, the 8-micron thick galvanized cold-formed thin-walled steel components can have a service life of 240 years under normal use conditions. However, the design lifespan of general residential buildings is only 60 years;

　　美國國家住宅研究中心NAHB對4棟地處環境較差寒冷或炎熱近海地域輕鋼住宅跟蹤取樣測試結果表明：目前采用的輕鋼鍍鋅構件住宅使用壽命可達100年以上；

　　The National Center for Housing Research (NAHB) in the United States conducted tracking sampling tests on four light steel residential buildings located in cold or hot coastal areas with poor environmental conditions. The results showed that the current use of light steel galvanized components in residential buildings can have a service life of over 100 years;

　　中國二汽掛片試驗得到: ?如十堰、蘭州、桂林、昆明等地干燥、無腐蝕介質條件， 五年腐蝕深度為：0.00327。

　　China Second Automobile Group's hanging test results:? Dry and non corrosive medium conditions in places such as Shiyan, Lanzhou, Guilin, Kunming, etc., with a five-year corrosion depth of 0.00327.

　　七、超輕鋼主體結構構件的特性

　　7、 Characteristics of ultra light steel main structural components

　　八、超輕鋼主體結構構件打包方式我們以房屋部件（如：墻體、屋架）進行打包，方便識別，裝卸便捷。

　　8、 The packaging method for the main structural components of ultra light steel is to package the building components (such as walls and roof trusses) for easy identification and convenient loading and unloading.

　　九、超輕鋼主體結構安裝步驟第一步:根據各部件圖紙把部件拼裝好，然后用自攻螺釘連接成整體第二步：根據地基放線把組裝好的部件放到指定位置，并用臨時支撐固定第三步：復檢尺寸及矯正龍骨第四步：調整好墻體位置后與基礎連接,部件與部件連接第五步：安裝墻面抗風拉帶和拉緊器等其他配件第六步：安裝屋架/樓板，完畢說明：多層房屋，安裝完樓板骨架后，安裝樓面結構板并固定一層墻面結構板后，再按第一步安裝二層框架。

　　9、 The first step of installing the ultra light steel main structure is to assemble the components according to the drawings of each component, and then connect them into a whole with self tapping screws. The second step is to place the assembled components in the designated position according to the foundation layout, and fix them with temporary supports. The third step is to recheck the dimensions and correct the dragon bones. The fourth step is to adjust the position of the wall and connect it to the foundation. The fifth step is to install the wall anti wind tension band and other accessories such as tensioners. The sixth step is to install the roof truss/floor slab. After installing the floor slab skeleton, install the floor structural plate and fix the first floor wall structural plate. Then, install the second floor frame according to the first step.

　　十、施工工藝流程1.基礎施工流程包括：測量放樣 → 地基驗槽 → 管道預埋 → 墊層澆筑 → 鋼筋綁扎 → 模板施工 → 隱蔽驗收 → 基礎澆筑 → 模板拆除 → 基礎驗收 → 基礎軸線放樣。

　　10、 Construction process: 1. The basic construction process includes: measurement and layout → foundation trench inspection → pipeline pre embedding → cushion layer pouring → steel bar binding → formwork construction → concealed acceptance → foundation pouring → formwork removal → foundation acceptance → foundation axis layout.

　　2.墻體系統施工流程包括：墻體測量放樣 → 墻架拼裝（若墻體為工廠拼裝，此步驟放在工廠完成）→ 防水、防潮膜（墊）鋪設 → 單片墻架安裝 → 臨時斜撐施工→ 墻體校正 → 墻體之間連接 ?→ 外墻體X 剪力鋼帶施工 → 墻體復檢 → 墻體抗拔、抗剪錨栓與基礎連接 → 墻面板（OSB板）安裝 →（水電管線安裝→填保溫棉→內側墻面板（石膏板））→ 呼吸紙安裝 → 保溫板安裝 → 刷界面劑 → 網格布或鋼絲網 → 砂漿 → 裝飾層。

　　2. The construction process of the wall system includes: wall surveying and setting out → wall frame assembly (if the wall is assembled in the factory, this step is completed in the factory) → waterproof and moisture-proof membrane (pad) laying → single wall frame installation → temporary slant support construction → wall correction → wall connection? → Construction of exterior wall X shear steel strip → Wall re inspection → Wall pull-out and shear anchor bolt connection with foundation → Installation of wall panel (OSB board) → (Installation of water and electricity pipelines → Filling of insulation cotton → Inner wall panel (gypsum board)) → Installation of breathing paper → Installation of insulation board → Application of interface agent → Mesh cloth or steel wire mesh → Mortar → Decorative layer.

　　3.樓蓋系統施工流程包括：

　　3. The construction process of the floor system includes:

　　樓板測量放樣 → 樓板邊導軌安裝 → 樓蓋梁安裝 → 梁端腹板加勁件、加勁短柱設置 → 樓蓋支撐系統安裝 → 樓蓋梁上貼雙面膠（3mm泡棉膠）→ 樓面板（OSB板）安裝 → 40厚細石砼（內配鋼絲網）澆筑→（水電管線安裝→填保溫棉→吊頂板（石膏板））→裝飾面層。

　　Floor measurement and layout → Installation of floor edge guide rails → Installation of floor beams → Setting of web plate stiffeners and short columns at beam ends → Installation of floor support system → Applying double-sided tape (3mm foam adhesive) on floor beams → Installation of floor slabs (OSB boards) → Pouring of 40mm thick fine aggregate concrete (with steel wire mesh inside) → Installation of water and electricity pipelines → Filling of insulation cotton → Ceiling board (gypsum board) → Decorative surface layer.

　　4.屋蓋系統施工流程包括：桁架測量放樣 → 桁架與墻體連接件安裝 →桁架安裝 → 校正 → 設置屋架支撐系統 → 小屋脊板、檐口安裝 → 屋面板安裝 → 大屋脊板安裝 → 防水卷材鋪設 → （水電管線安裝 → 填保溫棉 → 吊頂板（石膏板））→ 屋面瓦安裝。

　　4. The construction process of the roof system includes: truss measurement and layout → installation of truss and wall connectors → truss installation → calibration → setting up the roof truss support system → installation of small roof ridge and eaves → installation of roof panels → installation of large roof ridge panels → laying of waterproof rolls → (installation of water and electricity pipelines → filling of insulation cotton → ceiling panels (gypsum boards)) → installation of roof tiles.