Requirements for fixing waterproof backing board

1、 Overview of waterproof backing board

Waterproof backing board is an important component of building waterproofing engineering, mainly used for waterproofing treatment of walls, roofs, basements and other parts. It is usually made of polymer materials, modified asphalt or other waterproof materials, and has good waterproof performance, weather resistance and anti-aging ability. The correct fixation of waterproof backing board is a key link to ensure the long-term effective operation of the waterproof system. Improper fixation method may lead to problems such as damage and leakage of the waterproof layer.

2、 Preparation work before fixation

1. Requirements for grassroots treatment

Before fixing the waterproof backing board, the base layer must be thoroughly treated:

-The surface of the base layer should be flat, solid, free of looseness, sanding, cracks, oil stains, and other debris

-The moisture content of the concrete base should not exceed 9%, and the plastic film method can be used for testing

-The internal and external corners should be made into a circular arc shape or a 45 ° oblique angle, with a radius of no less than 50mm

-The protrusions on the surface of the base layer should be removed, and the depressions should be filled and leveled with cement mortar

-The surface of the base layer should be clean and dry, and can be cleaned with a vacuum cleaner if necessary

2. Material preparation

-The waterproof backing board should meet the design requirements and relevant national standards

-Fixed components (such as specialized adhesives, mechanical fasteners, etc.) should match the waterproof backing board

-Auxiliary materials such as sealant and waterproof tape should be fully prepared

3. Construction environment requirements

-The construction environment temperature should be between 5 ℃ and 35 ℃

-Construction is not allowed on rainy days, snowy days, or weather with winds above level 5

-It is expected that there will be rain and snow within 24 hours after construction, and construction should be suspended

3、 Fixed methods and technical requirements

1. Adhesive fixation method

(1) Full adhesion method

-Suitable for base layers with good flatness

-The adhesive should be evenly applied to the base layer and the back of the waterproof backing board

-The adhesive application area should not be less than 90% of the total area

-When pasting, it should be done in sequence from one end to the other, eliminating any air

-After pasting, gently tap with a rubber hammer immediately to ensure a firm bond

(2) Point sticking method

-Suitable for areas with slightly poor flatness at the grassroots level

-The adhesive is distributed in dots or strips with a spacing of no more than 400mm

-The adhesive area per square meter should not be less than 30% of the total area

-Fixed points should be encrypted at the edges

2. Mechanical fixation method

(1) Screw fixation

-Suitable for base layers such as concrete and steel structures

-Fixed component spacing: not more than 200mm around the perimeter and not more than 300mm in the middle

-The distance between the fixed parts and the edge of the board should be 20-30mm

-The fixed parts should use specialized waterproof screws and be equipped with waterproof washers

-The length of the screw should penetrate the base layer by at least 25mm

(2) Pressure strip fixation

-Suitable for large-area waterproofing projects such as roofs

-The spacing between the pressure strips should not exceed 500mm

-The width of the pressure strip should not be less than 40mm

-The distance between the fixing points of the pressure strip shall not exceed 300mm

-An elastic cushion layer should be installed between the pressure strip and the waterproof backing board

3. Hot melt fixation method

-Suitable for modified asphalt waterproof backing board

-The heating temperature should be controlled between 180-220 ℃

-The heating time should not be too long to prevent material aging

-After hot melting, it should be immediately compacted to eliminate air

-The overlapping part should be welded by hot melt welding

4、 Requirements for fixing detailed nodes

1. Yin Yang corner area

-Additional layers with a width of not less than 300mm should be added at the corners of yin and yang

-The additional layer should be fixed with adhesive first

-The main waterproof layer should avoid mechanical fixation at the internal and external corners

2. Root of pipeline

-The root of the pipeline should be treated with a conical frustum or an octagonal slope

-The waterproof backing board should be cut to match the shape of the pipeline

-Fixing should be done by combining adhesive and metal hoops

-The upper opening should be sealed tightly with sealing material

3. Deformation joint location

-A metal cover plate should be installed at the deformation joint

-The waterproof backing board should be fixed separately on both sides of the deformation joint

-The distance between the fixed point and the seam edge shall not be less than 100mm

-Elastic sealing material should be installed under the cover plate

4. Cornice area

-Metal pressure strips should be installed at the eaves

-The fixed spacing of the pressure strip shall not exceed 200mm

-The waterproof backing board should reserve a margin of not less than 50mm at the eaves

-The end should be sealed

5、 Fixed quality requirements

1. Appearance inspection

-The waterproof backing board should be flat, without wrinkles or bubbles

-The fixed points should be evenly distributed without obvious depressions or protrusions

-The joint area should be tight and free of curling edges

2. Bonding strength test

-The bonding strength of on-site pull-out test should not be less than 0.3MPa

-The number of tests shall not be less than 3 per 100 square meters

-Unqualified points should be reinforced

3. Sealing inspection

-There should be no leakage marks around the fixed point

-The joint area should undergo a water immersion or storage test

-The test time shall not be less than 24 hours

6、 Construction precautions

When laying waterproof backing boards, drainage slope should be considered, and fixing points should not obstruct drainage

2. Different fixing methods should not be mixed on the same construction surface

3. During the fixing process, mechanical damage to the waterproof backing plate should be avoided

4. Construction personnel should wear soft soled shoes to avoid trampling and damaging the waterproof layer

5. After the fixation is completed, the protective layer construction should be carried out in a timely manner

6. Insulation measures should be taken during winter construction to ensure the normal curing of adhesives

7. During the construction process, finished product protection should be done well to prevent subsequent processes from damaging the waterproof layer

7、 Common problems and solutions

1. Loose fixation:

-Reason: Inadequate grassroots treatment, improper selection of adhesive, excessive fixing spacing

-Solution: Add fixed points, replace adhesives, and reprocess the base layer

2. Waterproof backing board bulging:

-Reason: High moisture content in the base layer, uneven application of adhesive, incomplete exhaust

-Solution: Cut open the air release, reapply adhesive for fixation, and add pressure strips

3. Joint cracking:

-Reason: thermal expansion and contraction, improper fixing method, failure of sealing material

-Solution: Clean the seams, reseal, and add elastic pressure strips

8、 Acceptance criteria

1. Main control project:

-The quality certification documents for waterproof backing board and fixing materials are complete

-The fixing method and spacing meet the design requirements

-The processing of detailed nodes meets the requirements of the specifications

-The waterproof system has no leakage phenomenon

2. General projects:

-The surface of the waterproof backing board is flat and clean

-Fixed points arranged neatly without obvious defects

-The seam treatment is tight and aesthetically pleasing

-Finished product protection measures in place

9、 Maintenance requirements

1. Regularly check the sealing condition of fixed points and promptly address any issues found

2. Avoid drilling or nailing on the waterproof backing board

3. Avoid using sharp tools during cleaning

4. The fixed system should be thoroughly inspected every 2-3 years

5. During maintenance, materials and processes that match the original system should be used

10、 Safe and civilized construction

1. Clear safety warning signs should be set up on the construction site

2. When working at heights, safety belts should be fastened and a stable operating platform should be set up

3. During hot melt construction, attention should be paid to fire prevention and fire extinguishing equipment should be equipped

4. Construction waste should be classified and collected, and properly disposed of

5. Adhesive and other chemical materials should be stored in a well ventilated area

Through the detailed fixed requirements above, the construction quality of waterproof backing board can be ensured, the service life of the waterproof system can be extended, and reliable waterproof guarantee can be provided for buildings. During the construction process, strict adherence to design requirements and relevant national regulations should be implemented to ensure quality control at every stage.