Technical construction procedures of polyurethane waterproof coating

Polyurethane Waterproof Coating (PU coating) is a reactive moisture-curing one-component coating also a kind of polymer waterproof coating which is widely used for floor waterproofing, roof waterproofing and wall waterproofing works and many other civil engineering waterproofing and industrial waterproofing construction works.
 
I. Construction procedures
 

• Base course treatment → primer painting → construction waterproofing layer with polyurethane coating → construction of waterproof protective layer

 
II. Technical requirements for waterproof construction
 
1.Base treatment

• Before painting the waterproof layer with the liquid waterproofing polyurethane coating, clean the sundries and mortar hard blocks on the surface of the base course and wipe them with a clean wet cloth. The next process can be carried out only after the base course is checked to be free of defects such as unevenness, air crack and sanding.

2.Base primer application

• Preparation of primer (base course treatment agent): first mix the polyurethane waterproof coating with water in the ratio of 1:2 (weight ratio), and the prepared material must be used up within 2 hours.
• Primer brushing: evenly brush the prepared primer on the base surface with a long handle roller brush, with a brushing amount of about 0.3kg/m2. After about 4 hours, the next process can be carried out when the hand does not stick.

3.Construction waterproof layers with the polyurethane coating

• The polyurethane waterproof coating shall be well prepared for use. It shall be forcibly stirred with an electric mixer for 3 ~ 5 minutes until it is fully and evenly stirred. The stirred coating shall be used up within 2 hours.
• Additional waterproof treatment for the pipe root passing through the wall, top and ground, floor drain, drain outlet, internal and external corners, deformation joints and other weak parts, the reinforcement layer (additional layer) of the above parts shall be made before the large-scale construction of the coating layer.
• Painting and application of the first waterproof coating: after the material of the previous coating reinforcement layer is cured and dried, check whether there are residual bubbles in the additional layer. If not, paint the first coating; If there are bubbles or pores, press the mixture into the pores with a plastic scraper, brush the film locally, brush the film locally, and then construct the first layer of film.Apply and scrape the first layer of polyurethane coating waterproof material, which can be evenly applied and scraped with a plastic scraper to strive for the same thickness, about 100mm.
• Brushing the second waterproof coating: after the first coating is cured, the second coating can be evenly coated and scraped. The coating direction should be perpendicular to the coating direction of the first coating, and the layer thickness is the same, about 50mm. The interval between the second coating and the first coating is generally not less than 24 hours.
• The protective layer for the coating: after the last coating is cured and dried, the mortar or fine aggregate concrete protective layer can be constructed according to the appropriate form required by the architectural design.

III. Quality quarantee for the project

• The coating waterproof material must comply with the design and relevant standards, and have product certificate and test report.
• The coating waterproof layer and its local deformation that should be strengthened, the practices of embedded hangers and internal and external corners must meet the design requirements and the provisions of construction specifications without leakage.
• Before the coated film is cured, people and articles are not allowed to accumulate, so as to avoid damage to the waterproof layer of the film and leakage.
• Bulging: the base course has peeling, sanding, cracking and non drying, resulting in poor adhesion of the film;The base course construction shall be carefully operated and maintained. After the base course is dry, the bottom coating shall be applied first, and then cured, and then applied layer by layer according to the waterproof layer construction process.

IV. Civilized construction and environmental protection measures

• During the handling, loading and unloading of mechanical equipment, materials and materials, it shall be ensured that the built working wells and facilities are not damaged.
• During construction, a good working environment shall be maintained, and materials, tools and standby equipment shall be orderly.
• Take good care of construction machines, tools and materials and eliminate waste.

V. Safety technical measures:

•  Carry out mobilization training and safety education for construction personnel to make them have a comprehensive understanding of the material properties and safety measures used by construction personnel, and strictly implement the labor protection system during operation.
•  Special personnel shall be assigned to direct the vertical transportation of materials and cooperate up and down to avoid accidents.
•  It is strictly forbidden for the upper construction personnel to throw objects at will, and the tools shall not be placed at will to avoid falling and hurting people.
•  The scaffold and skid used for hanging waterproof must be laid stably without suspension, and the support must be firm. It can be used only after being confirmed by the security inspection personnel.
•  Carry out fire education and training for workers, and master the knowledge of fire prevention and extinguishing and the correct use of fire-fighting equipment.
•  Most waterproof materials are inflammable or chemical products, so a special material warehouse shall be set up. When facing the work, they shall be stored in a clean and dry place, away from the water source and fire source. Fireworks are strictly prohibited. On site operators are not allowed to smoke, with obvious signs and equipped with fire-fighting equipment.