I. Project Overview
It is proposed to use 1.5mm thick JS composite waterproof coating system to provide
indoor flexible waterproofing for the project.
II. Basis and Principles
1.Technical Code for Roofing Works (GB50345-2004)
2. Code for Quality Acceptance of Roofing Works (GB50207-2002)
3.Technical Code for Indoor Waterproof Works of Buildings (CECS196:2006)
III. Construction Conditions:
1. When delivered to site, waterproof materials must be inspected and tested again, and any material if unacceptable shall not be used.
2. Materials must be sealed and stored in cold and dry place and kept away from water.
3. Tools and manpower necessary for construction must be sufficient and well arranged.
4. Sufficient lighting and ventilation facilities must be provided to ensure the safety of construction work.
5. The indoor slope of drainage must be set according to design requirements.
6. The base layer shall be able to bear enough strength and the surface must be firm, smooth and contain no sand.
7. The surface of base layer shall be free of dust, oil, particles and other foreign matters.
8. The intersecting part between horizontal and vertical planes, the corners and the internal and external angles shall be plastered with cement mortar to small smooth round angles.
9. Pipes connected to base layer, through-wall pipes and floor drains shall be firmly installed before constructing waterproof layer.
10. Where around pipe roots, 10×10mm grooves shall be made and sealed with sealing paste. Pipe surface shall be roughened or treated for rust resisting.
11. The base layer of JS composite waterproof coatings shall be kept away from water.
IV. Construction Process:
(I) Construction Conditions
1. Base layer must be toweled, firm, free of defects such as bump, crack, sand and void, etc. Hand-over inspection shall be done together with supervision engineer.
2. Base surface shall be flat, smooth and even in thickness. The planeness of base surface shall be inspected with 2m straight edge, with the largest void no longer than 5mm and no more than one void for every 1 m2 area.
3. Base surface shall be dry, with water content lower than 9%. The water content can be determined by such method: pave 1m2 APP rolling material on the base in a smooth manner, and keep it that way for 3～4h, after that, check if there is any water mark on base surface and APP rolling material. No water mark means the paving work is satisfactory.
4. If base surface is ragged or contains big pit, the surface shall be made smooth with polyester cement mortar.
5. The internal and external angles at the intersecting part between horizontal and vertical planes shall be made to smooth round angle, with arc radius no smaller than 50mm.
6. Sharp and hard articles or sand pimples projecting from base surface shall be removed completely or plastered with polyester cement mortar with the arc radius of plastered area is greater than 300mm. Partial positions such as internal and external angles and pipe root shall be carefully cleaned. If any rust, abrasive paper, wire brush or solvent shall be used for cleaning.
7. Components to pass through base layer shall be installed before waterproof layer construction.
8. Waterproof material and system components shall be stored at dry and well-ventilated place to prevent sunshine, rain and fire source.
(II) Process Flow
Cleaning base layer→applying base layer treating agent→applying additional waterproof layer at connecting parts→line snapping→large-area applying APP waterproof rolling material→torch-applied lapping joint→inspection and acceptance
(III) Operating Keys and Technical Requirements
1. Cleaning base layer: Remove projecting matters and foreign matter on base surface. If any oil or rust, wire brush or organic solvent shall be used for cleaning.
2. Applying base layer treating agent: Apply treating agent on treated base layer with long-handle roller brush in an even manner, without missing any area or exposing the base. Only when base treatment is completed and dried to certain degree (no stick to hand), shall APP rolling material be installed.
3. Additional waterproof layer for partial positions: Before paving large-area APP waterproof rolling material, partial positions shall be provided with waterproof measures first, including roof gutter, eave gutter, flashing, internal and external angles, parapet, pipe root on projecting roofing and outfall, etc.
4. Construction method for partial positions:
(1) The intersecting parts between roof gutter, eave gutter and roofing shall be paved by periphery adhesion paving method with adhering width no less than 200mm. APP waterproof rolling material shall reach to the top of external side of gutter from gutter bottom and the closing end shall be fixed and sealed. (See the Figure)
(2) Parapet shall be set with flashing, with the closing end of APP waterproof rolling material set on the top of parapet or into the groove on parapet and fixed and sealed. (See the Figure)
(3) APP waterproof rolling material shall not be less than 50mm in storm inlet. (See the Figure)
(4) The flashing height of movement joint shall not be less than 250mm. APP waterproof layer shall be paved on the upper part of masonry at both sides of movement joint. Movement joint shall be filled with cushion material and covered with APP waterproof rolling material. (See the Figure)
(5) Pipe root projecting from roofing shall be provided with additional waterproof layer at periphery, with the width or height no less than 300mm. The closing end of waterproof layer shall be fixed with metal fittings and filled with sealing material. (See the Figure)
(6) Waterproof method for other positions is detailed in attached figures. If any unconformity between the Proposal and the site (due to limited sources of engineering information), adjustment can be made according to site conditions.
5. Large-area pavement of APP waterproof rolling material:
For large-area pavement, it is better to adopt rolling pavement method. When paving is finished, then treat lapping joint by torch-applied bonding.
(1) Line snapping: The dimensions (80mm wide for both long and short sides) of lapping joints shall be determined according to the width of APP waterproof rolling material and set on base surface that has been treated and dried. Then, the baseline for paving APP waterproof rolling material shall be snapped.
(2) Torch-applied paving rolling material: Put the whole roll of APP waterproof rolling material at the starting end and spread rolling material against the baseline for a length of about 1m. Pull up the 1m material by a person from the front side of material, heat the glue on the back side of material by another person with a spray lamp, and adhere it to the base when the glue is melted. After that, fix the end of rolling material and compact tightly.
When the section firmly adheres to base layer, the person with the spray lamp shall wait ahead for the next section to be paved till the whole roll of material is paved. When heating APP waterproof rolling material and base layer, the spray lamp shall be kept in a distance 0.3～0.5m away from the positions to be heated and shall move back and forth (the flame shall not stay at one position for a long time, otherwise the base may be exposed or the base material of modified asphalt may fall apart immediately). The heating shall be done evenly to prevent high temperature or material burning. As long as the glue at back side of rolling material becomes black and has few micro bubbles (a large amount of bubbles are not allowed), the material roll shall be further spread immediately. A third person shall follow behind to remove air and compact the material.
(3) The lapping joint and closing end of APP waterproof material must be evenly and fully heated to ensure tight bonding between APP waterproof materials at lapping joints and that melted asphalt glue could be squeezed out from the edge. Then spread the asphalt glue and use it to seal the edge so as to ensure the tightness of lapping joints.
6. Inspection and acceptance: When paving APP waterproof rolling material, lapping
joints shall be inspected with screw driver. If any boding is not tight, repair shall be made at once. Construction personnel and quality inspector shall carry out inspection from time to time. Only when previous work is considered acceptable, the next step can be constructed. Attention shall be paid to ensure correct paving method is adopted for partial positions.
Construction Process of JS Composite Waterproof Coatings
Cleaning base layer→Making additional waterproof layer for pipe roots, internal and external angles→first film of waterproof coating→second film of waterproof coating→third film of waterproof coating→24-hour water storage test→inspection and acceptance
1. Base-layer treatment:
The surface of base layer shall be clean, free of projections and foreign matters. Such dirt as oil and rust must be completely removed with wire brush or organic solvent. After cleaning, the surface shall also be wetted, but attention must be made to prevent water accumulating on the surface.
2. Additional waterproof layer for partial positions:
Before large-area coating, an additional waterproof layer with reinforced cloth shall be set at partial positions such as pipe root, internal and external angles according to the following steps. Firstly, apply a layer of waterproof coating evenly on the surface with painting brush or rubber scraper, then immediately attach reinforced cloth. When applying reinforced cloth, use paint brush to pack it to good leveling and best contact with underneath coating, with overlapping width of 100mm, then apply one-two passes of paint on the surface to satisfied thickness.
3. Construction of the first film of waterproof coating:
Before applying the first layer, the JS composite waterproof coating shall be formulated to required grade and mixed evenly, then apply a very thin layer of coating on the base surface with paint brush or rubber scraper. After that, apply the coating evenly according to required thickness.
4. Construction of the second film of waterproof coating:
Apply the same coating a second time in the same way. The painting direction of the second time must be vertical to that of the first layer. The amount of coating shall be the same as that of the first layer.
5. Construction of the third film of waterproof coating:
When the second layer becomes dry, apply the third layer in the same way as above. The painting direction of this time must be vertical to that of the last time. The design requirements must be met and the overall thickness of waterproof layers must be 1.5mm.
6. Water storage test:
Following the completion of coating work, 24h water storage test is carried out for leak inspection, and no leakage means ready for acceptance.
V. Finished Product Protection
1. Since the flexible waterproof system composed of JS composite waterproof coating is relatively weak, it must be protected appropriately from damage.
2. The waterproof layer without protection shall not bear heavy load or contact with
articles with sharp angles to prevent damage.
3. For protecting waterproof layer, construction workers shall wear soft-sole shoes and are not allowed to wear spiked shoes. Any damage to waterproof layer, if found, shall be repaired immediately.
4. During the operation of APP waterproof rolling material system for roofing works, regular inspection shall be carried out and foreign matters (leaves, etc.) on roofing shall be removed from time to time to make sure downpipe smooth.
VI. Construction Precautions
1. The coating for internal and external angles shall be even and in plural and shall be applied after wall painting is finished to prevent coating accumulation and cracking due to uneven thickness. 1-2 hours after wall painting is finished, additional coating shall be applied according to the degree of coating accumulating or falling so as to make sure the surface of internal and external angles and wall is in the same plane and prevent coating cracking.
2. Before applying waterproof layer, pipes and buried parts shall be installed and fixed firmly so that there will be no need to making holes in the future that may damage waterproof layers and cause leakage.
3. When igniting or heating, be careful to keep flame spray nozzle away from person.
4. Construction site shall be clear of inflammable or explosive substances. Fire
fighting equipment shall be available at site and smooth traffic for fire fighting shall be maintained in case of fire.
5. Inflammable or explosive substances necessary for construction shall be stored at
special place, and kept safe by special person.
6. Gasoline torch and other inflammable substances must be put in specified store
attended by special person.
7. In case of grade 5 wind or above, the construction of APP waterproof rolling
material shall be stopped.
8. Quality Problems:
1) Void and bubble in film waterproof coating: The problem may come from two aspects. The mixing method or time of coating materials is inappropriate, leading to uneven mixing, which can be solved by using mixers with high power and small rotation. Another reason may be that the base layer is not clean. Therefore, before painting, the base layer shall be cleaned thoroughly, free of foreign matters or dust, or any void. If any void, it shall be treated according to process requirements to prevent damage or leakage to coating film.
2) Bump in film waterproof coating: The base layer has scale or sand that may cause bad bonding. So the base layer shall be applied and protected properly. When the bottom layer is finished and solidified, other layers shall be painted one by one according to construction process.
4) Breaking of film waterproof coating: The coating film may be broken or scratched if workers walk on coating layers or put tools or materials on coating layers during the construction of film coating layers or when all coating work is finished but waterproof layers haven’t been solidified. Appropriate protection measures shall be provided while coating work is being done.
1. Acceptance shall be carried out according to codes and standards, including Technical Code for Roofing Works (GB50345-2004), Code for Quality Acceptance of Roofing Works (GB50207-2002) and Technical Code for Indoor Waterproof Works of Buildings (CECS196:2006).
2. During the construction of waterproof layer, every each layer is completed, strict inspection shall be made by special persons respectively from work team, construction team and quality inspection department. Only when one layer is considered acceptable, the next layer can be constructed.
3. Hand-over inspection for every item shall be carried out one by one by relative parties, and submitted for acceptance before covering work is done. No subsequent work shall be done when previous work has not been approved.
VIII. Quality Assurance Measures
1. The Construction Proposal, national standards and codes shall be complied with during the construction of waterproof works.
2. Construction workers must be well trained and have work permit.
3. Waterproof materials delivered to site shall be subject to spot check. Unacceptable materials shall not be used.
4. Construction work shall be arranged in a reasonable manner. Self-inspection shall be carried out strictly to make sure each work step is of good quality.
5. Construction quality, process and safety shall be supervised and managed by management personnel.
IX. Safety and Civilization Construction Measures
1. Safety and civilization construction system shall be implemented strictly to set up a civilized circumstance at construction site, make sure the safety of construction and build up a good company image.
2. Have a good understanding of and strictly comply with state and government project management systems with regard to construction safety and civilization, impact on surrounding residents and noise control.
3. A complete set of work responsibility system shall be set up and strictly implemented.
Examination on construction civilization shall be carried out.
4. Fine management shall be implemented. For example, workers shall stand in queue
when entering into or leaving plant. It is prohibited to drink wines in work. Uniforms shall be worn in work.
5. Set up and implement power safety system during construction.
6. Make sure construction site is cleaned and residual material is disposed properly
when construction work is completed.
X. Fire Fighting Measures
1. Fire Protection Regulations of the People’s Republic of China and the General Waterproof Measures for Construction Site issued by Ministry of Public Security shall be strictly implemented.
2. Sufficient fire fighting equipment shall be provided at construction site, administrated and maintained by special persons and inspected regularly.
3. Construction site shall be divided into respective zones for fire work, inflammable material storage and living, and these zones shall be kept in appropriate fire separation distance.
4. Open fire management system shall be set up at construction site.
Ⅺ. Rainproof Measures in Construction Period
1. If the base-layer treating agent needs to be painted beforehand, it can only be half a day earlier than paving.
2. Large-area pavement of SBS rolling material shall be done in parallel with construction of partial positions and joints sealing. At the end of every working day, no closing end or edge can be left unfinished.
3. At the end of every day, the rolling material that has been applied shall be adhered tightly to base layer to prevent rainwater entering into the bottom of the rolling material.
4. If there is any sign of rainfall by exact forecast, the base layer that has already been provided with a part of waterproof measures shall also be provided with covering facilities to prevent water entering into the base layer.