The detailed structure of the joints of the roof waterproof project is an important part of the waterproof project. The leakage of the roof often comes from the above parts. In addition to the construction influencing factors, it is particularly important to do all the detailed structural treatment and related technical design. ­

1 Detailed structure of nodes
The roof waterproof engineering nodes are generally many and complicated. Different structures, forms and materials have different designs. Numerous nodes include: roof eaves, gutters, water dropouts, flooding, pressure roofing and deformation joints, lattice joints, waterproofing pipelines, embedded parts, access holes, construction joints, floor drains and waterproofing joints Close and so on.

1.1 Principles of node design
1.1.1 Comprehensively consider the structural deformation, temperature difference deformation, dry shrinkage deformation, vibration and other factors. Additional layers should be added on the node fortification to adapt to the deformation of the base layer. In the construction of the waterproof layer, the empty paving method is appropriate, and high elasticity and high extension materials can be used for corresponding treatment in the selection of materials.
1.1.2 Adopt the combination of flexible sealing, anti-discharge, and the combination of materials and construction waterproofing.
1.1.3 Nodes should be designed with complementary multi-channel fortifications such as coiled material, paint, seals, and rigid waterproof materials. ­
1.1.4 Consider the overall fortification capability. The focus is on waterproof and durable years. For this reason, the performance indicators of the materials used on the nodes should be higher than other parts, especially the aging resistance is better. ­
In addition, because each building is not necessarily all the same, individual design is still required. At this time, the design of the node should be spiritual, that is, refer to the design principles and standards and combine the specific circumstances to design, it is not appropriate to apply standard drawings uniformly. ­

1.2 Design of main nodes
According to the requirements of the national standard GB50207-94 (roof engineering technical specification), the design of the main node structure is as follows.
1.2. 1 cornice
Unorganized drainage cornices are divided into prefabricated and integral cast-in-place types. Most of the ends of the cornice are embedded with sealing materials. Design and treatment: There is a groove at the end of the cornice, and the end is pressed into the groove to fix it, the sealing material is tightly sealed, and the top can also be wiped with cement mortar. ­
1.2.2 Gutters and Yaogous
The design of gutters and gutters should determine the drainage slope. In addition, for the places where deformation cracks are prone to occur, such as gutters, gutters and roof joints, additional layers are added and empty paved, and the width of the empty paving should be 200mm. The waterproof layer of the outer eaves seal should be fixed at the end and sealed with cement mortar.
1.2.3 Water drop and floor drain
The design of the water drop should select the water drop fittings and the diameter of the water drop that are compatible with the waterproof material. There is a groove at the junction of the water drop and the base layer, and the sealing material is embedded and fixed. The elevation and slope of the water outlet should be reasonably determined. Generally, the drainage slope within 500mm around the water outlet is not less than 5%. It is better to choose paint for waterproof material, make it into a seamless coating film, and lay additional layer and waterproof layer. ­
1.2.4 The end of flooding
Mistakes in flooding treatment are one of the causes of leakage, and there are currently three improvements:
(1) When the flooding of the brick parapet is not high, the coiled material can be directly laid under the top of the parapet, and the top should be waterproofed. ­
(2) When the wall is a brick wall, leave grooves and do not make eaves. In the past, the eaves often cracked, causing water to seep into the room from behind the waterproof layer. In the current design, the end of the waterproof layer is fixed and sealed into the groove, the minimum height of the groove from the roof leveling layer should not be less than 250mm, and the upper wall of the groove should also be waterproofed. ­
(3) When the wall is made of concrete, the end of the coiled material can be nailed with metal beading and embedded with sealing material. ­
1.2.5 Press top
In the past, most of the topping designs were bricklaying, cement mortar, or precast concrete blocks, and the topping method of cast-in-place concrete. But from time to time shrinkage, cracking and leakage occurred. For this reason, metal pressing has been changed or synthetic polymer coil pressing has been adopted so as to increase the pressing fortification. ­
1.2.6 Deformation joint
It is divided into general deformation joints and high and low span deformation joints. Deformation seam design: the seam should be filled with foam plastic or asphalt hemp, the upper part is filled with cushioning material, and covered with high extension and high strength coiled material. Concrete cover or metal gland should be buckled on the top.
In the past, there was a method of eaves elevating between high and low cross-deformation joints, but the operation was difficult. Now it is also changed to coil material sealing treatment, and a metal covering plate is used for external protection.
1.2.7 Pipes passing through waterproof layer
There are various types of pipes, including steam pipes extending out of the roof, pipes passing through the bathroom, pipes passing through the basement and the reservoir, etc. In order to prevent the shrinkage of the concrete and the cracks caused by the separation of the pipe circumference, there must be a groove between the pipe and the concrete during the design, generally 20 X 20 (mm), filled with sealing material, and the pipe root is raised Make a 1/10 drainage slope to facilitate drainage, and then make a waterproof layer. The pipe extending out of the roof waterproof layer also requires the waterproof layer and the pipeline to be firmly tied, and then sealed with a sealing paste. The basement, water storage tank and bathroom adopt casing waterproofing treatment, that is, the concrete is buried before the concrete is poured, and several water stop pieces are welded. When the pipeline passes through the casing, the two ends are filled with sealing material. ­
1: 2.8 entrance and exit
There are horizontal and vertical entrances and exits. The horizontal entrances and exits are mostly the horizontal entrances and exits where the doors are opened. The waterproof layer of the entrances and exits should be pressed against the concrete steps. The waterproof layer of the vertical entrance and exit of the roof should be pressed under the concrete topping ring. ­
1.2.9 Split seam
Common compartmental joints include structural layer, leveling layer, rigid waterproof layer compartment. The waterproof treatment of the grid seam can be filled with sealing materials, laid with coiled material, or tiling. Generally, the width of the seam of the embedded seal is no more than 40mm, and the smallest is not less than l0mm. An additional protective layer should be added to the exposed compartment.
1. 2.10 Construction joint
Waterproof concrete is generally not allowed to retain construction joints. In underground buildings, storage tanks and other projects, horizontal construction joints can be left on the vertical wall. The construction joints are divided into structural construction and material water-proof construction joints, which are not described here.

2 Design of exhaust roof, steam barrier, separation, stripping, etc.
2.1 Exhaust roof
Exhaust roof is also called “breath roof”. If the water content of the heat insulation layer and the leveling layer is too large or it does not dry when immersed in rain, and the waterproof layer must be laid on it, the insulation layer may fail or the waterproof layer may bulge, affecting the quality. Therefore, the roof should be considered as an exhaust roof. ­
The design of the steam exhaust roof is to leave vertical and horizontal channels or buried perforated thin tubes in the insulation layer, and set vertical steam exhaust holes (tubes) at the intersections, so that the gas after the water is evaporated can be smoothly discharged into the atmosphere. ­
The exhaust channel formed by the retaining groove is 20 ~ 40mm, the exhaust tube diameter is §25, and it coincides with the leveling layer division gap.
The exhaust duct spacing should be 6m, set vertically and horizontally, and every 36 square meters of roof area should be equipped with an exhaust hole. The exhaust hole should be waterproof.
2.2 Vapor barrier ­
Make a waterproof layer under the insulation layer called vapor barrier. Insulation layer often contains retention water for construction leveling layer maintenance and water seepage when the waterproof layer fails. In order to improve the waterproof quality, the vapor barrier is designed according to certain conditions, and the specifications restrict the use of the vapor barrier. In the area north of latitude 40 ° north and the indoor air humidity is greater than 70%, or the indoor air humidity in other areas is always greater than 80%, the thermal insulation roof can be designed with a vapor barrier.
2.3 Break away
Detachment, also known as isolation, refers to the isolation measures taken during the design between the structural layer and the waterproof layer to avoid the mutual influence of deformation. For example, there is a non-bonding isolation measure between the rigid waterproof layer of fine stone concrete and the structural base layer, or “detached roof”. The materials of the isolation layer include paper-ribbed ash, low-grade mortar, sand layer, plastic film, dry linoleum, etc. ­
For the parapet of a building, the gable is cracked due to the thermal expansion and contraction of the roof structure layer. When designing, the gap between the structural layer and the parapet should be considered. ­
An isolation layer should be provided between the flexible waterproof material, the metal waterproof material and the rigid protective layer, and between the rigid waterproof layer and the base layer to ensure that the waterproof layer is not damaged. ­
2.4 Stripping
The base layer is cracked, and the coiled material or the coating film is stretched. If the waterproof layers on both sides of the seam are too firmly bonded to the base layer, the waterproof layer cannot handle the extension and break. At this time, the waterproof layer on both sides of the seam needs to be stripped, and the waterproof layer in the stripping area participates in the extension. The size of the peeling zone is related to the bonding strength. The stronger the bonding, the more difficult the peeling. The size of the peeling zone is proportional to the tensile strength of the material. The higher the tensile strength of the material, the easier it is to peel off.

3 Roof slope design and catchment area
If conditions permit, appropriately increasing the slope of the flat roof is beneficial to the rainwater roof to prevent seepage and drain.
3.1 When the slope height of the roof is below 25%, coiled material should be used instead of paint.
3.2 Slope search for structures refers to the elevation of one side of the roof slab, and its slope is 3%. For thermal insulation materials, the slope is 2% ~ 2.5%. ­
3.3 The slope width of the roof is greater than 18m, it is better to use the structure to find the slope, especially with the ceiling decoration under the roof panel, the structure is more suitable for slope detection. ­
3.4 In the northwest region with little rain, the slope of the flat roof is appropriately reduced, which can be less than 2%. Unstructured drainage can be done on the floors below five floors. ­
3.5 The slope of the gutter and eaves is 1%, and the water drop in one direction shall not exceed 200mm.