Waterproof Drawings for Roof of Light Steel Structure Prefabricated Houses

The waterproof drawings for the roof of light steel structure prefabricated houses typically include the following key elements:

1. General Description of Steel Structure Design
This is the core guiding document of the drawings, specifying the design basis for the light steel structure (such as load codes and seismic grades), material selection standards (such as steel grades and zinc coating thickness), waterproofing grade requirements (e.g., roof waterproofing grade II or I), and construction process specifications. For example, the general description may stipulate that the roof slope must be ≥5% to ensure drainage efficiency or require that all joints be sealed with silicone weather-resistant sealant.

2. Roof Structure Layout Drawings
These include plan and sectional layout drawings of steel beams and purlins. As the primary load-bearing components, the span and spacing of steel beams directly affect the roof's waterproofing performance; purlins must be evenly spaced (typically 600-900mm) to provide support for the roof panels. For instance, in a certain project, the steel beams are spaced 6m apart, and the purlins are C-shaped steel with an 800mm spacing, ensuring uniform stress on the roof panels and preventing waterproofing layer cracking due to deformation.

3. Roof Panel and Waterproofing Layer Design Drawings
These must indicate the type of roof panels (such as color-coated steel sheets, resin tiles, or metal composite panels), their thickness, and connection methods. The waterproofing layer design should specify the laying direction, lap width (usually ≥80mm), and fixing method (such as mechanical fastening or full adhesion) of the waterproofing materials (such as TPO or PVC waterproofing membranes). For example, a resin tile roof requires a waterproofing underlayment to be laid on the purlins before installing the tiles to ensure that rainwater cannot penetrate.

4. Detailed Node Drawings
These focus on the waterproofing construction of easily leak-prone areas such as ridges, eaves, gutters, and wall penetrations. For example, the ridge should be designed with double-slope drainage and covered with galvanized steel sheets; the eaves should have a drip edge to prevent rainwater backflow; gutters should have a reserved drainage slope (≥1%) and be equipped with drainage strainers to prevent clogging. Detailed node drawings should indicate material dimensions, welding requirements, and sealing treatment methods.

5. Drainage System Design Drawings
These include the location, quantity, and diameter selection of downspouts. Light steel structure roofs typically use natural drainage, requiring the calculation of drainage volume based on the roof area to reasonably arrange downspouts. For example, a 1200㎡ roof may require six Φ110mm downspouts to ensure smooth drainage during heavy rain.

Additional Design Considerations: Waterproofing for light steel structure roofs should follow the principle of 'combining prevention and drainage,' achieving rapid drainage through reasonable slope design (typically 3%-5%) while using weather-resistant waterproofing materials and reliable node construction to ensure long-term waterproofing of the roof.