塑料茅草屋面的施工工艺的大同小异
塑料茅草，尽管茅草的材料有所不同，但各个国家和地区的施工方法、施工工艺大同小异。
(一)茅草的准备
首先要选择相对饱满和结实的秸秆或棕榈叶，在温度约为30°～35°以及略微潮湿的条件下使茅草自然干燥。由于茅草极易燃烧，因此依据相应地区的施工要求，可以对干燥的茅草进行防火的处理，以降低茅草的易燃性。茅草处理后，可以选择麻绳和铁丝等将其捆扎为直径为7～12cm的单元，以便最终使用。
(二)搭设屋架
茅草屋面主要选择铺在木屋架上。我国传统的木屋架主要为人字形屋架，而在非洲等地，异形人字形屋架较为普遍。这类屋架安装有别于我国屋架的安装形式，施工步骤如下：
1.在室内的中间固定2根临时立柱，到要求屋面标高的位置。根据室内面积的不同，可以对称固定3个或多个立柱。
2.在2根或多根立柱上，固定一根横木，作为脊檩。
3.对称安装椽子，一端固定在横木上，一端固定在墙体上或梁上。如果固定在梁上，在浇筑梁的时候预留相应的铁丝或直径8～12mm的钢筋，间距约为1～1.5m。
4.按施工要求，安装斜柱以及檩条以加固屋架。檩条的间距约为0.5～0.7m，并和茅草单元的长度成正比。
5.当屋面茅草铺放完后，从距离立柱上端0.8～1.2m处锯断。
(三)茅草的铺放和绑扎
铺放茅草是按从下往上的顺序，一层压住一层，用尼龙绳或铁丝将茅草绑扎在檩条上，并用木刷将其梳理整齐，特别是茅草的根部。茅草的搭接处尽量使其落在檩条处，将其遮住，以提高室内屋顶的整体性、美观性。由于茅草较为光滑，不宜直接蹬踏在茅草上作业，选取一根圆木固定在完成部位的茅草上，待茅草铺放完毕后，从上到下将圆木依次拆除。
茅草屋面的坡度控制在35°～40°，既有利于雨水的排放也能创造更大的室内空间。茅草的厚度约为15cm，茅草的密实度约为20～25kg/m2，茅草密实性强并不表明屋面性能好，它和所选取的茅草的种类和质量有很大关系。屋脊地方要选取柔韧性较好的茅草，而且茅草铺放完毕后，可以做适当的防水处理，如用添加防水剂的水泥砂浆掩盖在屋脊的茅草上。
(四)防火防虫处理
茅草具有较强的易燃性，一旦引燃，不易扑灭，因此采取行之有效的防火措施至关重要。常用方法有铺放防火卷材、喷洒防火剂、烟雾感应器等。防火卷材可以铺放在结构和茅草之间。国外有些地方用铝箔纸作为选取的材料铺放在茅草下，它不仅具有遏制明火的作用，而且具有很好的绝热性。喷洒防火剂可以在室内外都进行喷洒，以提高屋面的防火性能。防火措施采取的得当，可以为居住着获取宝贵的逃生时间。在建筑茅草房屋时要特别注意电线电缆的铺设位置以及漏电保护措施等，使用时则应尽量避免室内出现有危害性的明火。
厚厚的茅草是昆虫理想的栖息和繁殖的基地，而且其遭虫吃的危害性很大。在防虫措施上，一方面要进行喷洒除虫剂，一方面要做好茅草的清洁维护。
(五)茅草屋面的维护
茅草屋面的寿命大约为28年，因材料不同而又有差异。小麦和水稻秸秆约20～30年，棕榈约30～40年。茅草屋面的使用离不开及时适当的维修。通常情况下，经常的维护可以再延长10年左右，特别是屋脊的茅草，每隔6～8年需更换一次。茅草维护中还要对茅草面进行梳理，避免茅草翘起、鸟类做巢。
好的茅草屋面取决于屋面的形状坡度、房屋位置、茅草材料以及施工人的经验等，因此施工时要综合考虑各方面的因素。【塑料茅草】
The construction technology of plastic thatched roofs is very similar.
Plastic thatch, although the material of thatch is different, but the construction method and construction technology of each country and region are very similar.
(1) preparation of thatch
The first step is to select relatively plump and strong straw or palm leaves, in the temperature of about 30 degrees to 35 degrees and slightly humid conditions to make the natural drying of thatch. Because thatch is very combustible, according to the construction requirements of the corresponding areas, the dry thatch can be fireproof treatment to reduce the flammability of thatch. After thatch treatment, hemp rope and iron wire can be selected and bundled into 7-12 cm diameter units for final use.
(two) erection of roof truss
Thatch is the main choice for thatching. The traditional wooden roof truss in China is mainly zigzag roof truss, while in Africa and other places, the special-shaped zigzag roof truss is more common. The installation of this kind of roof truss is different from that of the roof truss in China. The construction procedures are as follows:
1. fix 2 temporary columns in the middle of the room to the required elevation of the roof. According to the different indoor areas, 3 or more columns can be symmetrically fixed.
2. on 2 or more columns, a crossbar is fixed as a ridge purlin.
3. symmetrical installation of rafters, one end fixed on the crossbar, one end fixed on the wall or beam. If fixed on the beam, the corresponding wire or 8-12mm steel bar should be reserved when pouring the beam. The spacing is about 1-1.5m.
4. according to construction requirements, install inclined columns and purlin to strengthen the roof truss. Purlin spacing is about 0.5 ~ 0.7m, and directly proportional to the length of thatch unit.
5. when the roofing thatch shop is finished, it is sawed off from 0.8 to 1.2m above the top of the column.
(three) planting and binding of thatch grass
The laying of thatch is in the order from bottom to top, pressing one layer at a time, using nylon rope or wire to tie the thatch to the purlin, and combing it with a wood brush, especially the root of the thatch. The overlap of thatch should be placed on the purlin as far as possible to cover it so as to improve the integrity and aesthetics of indoor roof. Because of the smoothness of the thatch, it is not suitable to pedal directly on the thatch. A log is selected to be fixed on the thatch. After the thatch is laid, the logs are removed from top to bottom.
The slope of thatched roof should be controlled between 35 and 40 degrees, which is conducive to the discharge of rainwater and the creation of larger indoor space. The thickness of thatch is about 15cm, and the density of thatch is about 20-25kg/m2. The high density of thatch does not indicate good roofing performance. It is closely related to the type and quality of thatch. The roof should be made of flexible thatch, and the thatch can be properly waterproof after laying, such as using cement mortar with waterproof agent to cover the thatch on the roof.
(four) fire prevention and pest control
Thatch has strong flammability, once ignited, it is not easy to extinguish, so it is very important to take effective fire prevention measures. Common methods include laying fireproof rolls, spraying fireproofing agents, smoke sensors, etc. The fireproof coil can be laid between the structure and thatch. Aluminum foil paper is used as a selected material to lay under thatch in some foreign countries. It not only has the effect of curbing open fire, but also has good insulation. Sprinkler fire-retardant can be sprayed indoors and outside to improve the roof's fire resistance. Proper fire prevention measures can provide valuable escape time for residents. In the construction of thatched houses, special attention should be paid to the laying position of wires and cables and leakage protection measures, etc., when used, should be as far as possible to avoid indoor harmful open fire.
Thick thatch is an ideal habitat for insects and breeding, and it is very harmful to insects. On pest control measures, spraying insecticides on the one hand should be cleaned and maintained on the one hand.
(five) maintenance of thatched roofs
The life of thatch roofs is about 28 years, because of different materials and differences. Wheat and rice straw are about 20~30 years old, and palm is about 30~40 years old. The use of thatched roofs is inseparable from timely and proper maintenance. Usually, regular maintenance can be extended for another 10 years or so, especially for roof grass, which needs to be replaced every 6 to 8 years. In the maintenance of thatch, we should comb the grass surface, avoid thatching and birds nest.
A good thatched roof depends on the shape and slope of the roof, the location of the house, the material of the thatch and the experience of the builder. Therefore, all factors should be considered in the construction. [plastic thatch]
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