Detailed explanation of the method for fixing the inner corner of waterproof backing board

1、 The importance of fixing the inner corner of waterproof backing board

In building waterproofing engineering, the inner corner is a weak link that is prone to leakage problems. Yinjiao refers to the concave corner area at the junction of two walls or the ground and the wall surface. Due to factors such as stress concentration and material shrinkage deformation, these areas are prone to cracking, leading to the failure of the waterproof layer. As an important component of the waterproofing system, the quality of the internal corner fixation of the waterproof backing board directly affects the service life and waterproofing effect of the entire waterproofing project.

The correct method of fixing the inner corner can:

1. Ensure the continuity and integrity of the waterproof layer at the internal corners

2. Disperse stress and reduce the risk of cracking

3. Improve the overall integrity and durability of the waterproof system

4. Provide a good base for subsequent waterproof coating or roll construction

2、 Preparation work before fixing the inner corner of waterproof backing board

1. Grassroots treatment

Grassroots treatment is an important preparation work before fixing the waterproof backing board:

-Remove impurities such as dust, oil stains, and loose materials from the surface of the base layer

-Repair holes and cracks in the base layer to ensure a smooth surface

-For concrete base layer, it is necessary to check for defects such as honeycomb and rough surface and carry out treatment

-The moisture content of the base layer should meet the material requirements, generally not exceeding 8%

2. Material preparation

-Waterproof backing board: select specifications and materials that meet the design requirements

-Special adhesive: Select the matching adhesive according to the backing board material

-Auxiliary materials: sealant, waterproof tape, metal pressure strip, etc

-Tools: cutting tools, spatula, roller, hot air gun, etc

3. Measurement and laying out

-Measure and set out according to the design drawings and actual site conditions

-Mark the laying position of the backing board and the internal corner treatment line

-Calculate the cutting size of the backing board and minimize the seams as much as possible

3、 Method for fixing the inner corner of waterproof backing board

1. Direct pasting method

This is a commonly used method for fixing internal corners, suitable for most waterproof backing boards:

1. Cutting of backing plate: Cut the backing plate according to the size of the inner corner, and the length should exceed the inner corner by at least 100mm

2. Adhesive coating: Apply adhesive evenly on the back of the backing board and the base layer

3. Positioning and fixation: Align the backing plate with the concave corner position and start pasting from one end

4. Compaction treatment: Use a roller or trowel to compact from the middle to both sides, eliminating bubbles

5. Joint treatment: The overlapping width of adjacent backing plates shall not be less than 50mm, and the joint shall be treated with sealant

2. Mechanical fixation method

For special parts or projects with higher requirements, mechanical fixation assistance can be used:

1. Positioning drilling: Drill holes on both sides of the corner according to the design spacing

2. Install fasteners: Use specialized plastic expansion bolts or metal pressure strips to fix them

3. Sealing treatment: Use sealant around the fixed parts for waterproof sealing

4. Surface coverage: After fixation, the surface is covered with a layer of waterproof tape or coating

3. Prefabrication method

For highly standardized projects, prefabricated corner fittings can be used:

1. Prefabricated corner fittings: Factory prefabricated into L-shaped or arc-shaped corner backing plates

2. On site installation: directly insert it into the female corner for fixation

3. Joint treatment: Seal the overlap with the flat backing plate

4. Hot melt welding method

Suitable for thermoplastic waterproof backing board:

1. Edge treatment: Cut the edge of the backing board into a 45 ° oblique angle

2. Hot melt welding: Use a hot air gun to weld two backing plates at the internal corners

3. Pressure shaping: Immediately use specialized tools to press and shape after welding

4. Inspection and acceptance: Check whether the weld seam is continuous and dense

4、 Special part handling techniques

1. Handling of the junction of yin and yang corners

When the yin corner is adjacent to the yang corner, the processing sequence should be yin corner first and then yang corner:

1. First, complete the fixing of the inner corner backing plate

2. Cover the male corner backing plate with the female corner backing plate

3. Strengthen the joint with sealant

2. Root treatment of pipelines

Key points for fixing the internal corners of pipelines passing through walls:

1. Cut the backing plate into an arc shape that matches the pipeline

2. Install using the sleeve cutting method, tightly fitting the pipeline

3. Seal the surrounding area of the pipeline with sealant in a circular manner

3. Deformation joint treatment

Special treatment method for deformation joint corner:

1. The backing plate is broken at the deformation joint

2. Fill the gap with elastic sealing material

3. Surface covered with waterproof tape or metal cover plate

5、 Key points of quality control

1. Material quality control: All materials should have qualification certificates and testing reports

2. Process control: Strictly follow the construction process requirements for operation

3. Node inspection: Focus on inspecting key parts such as corners and pipe roots

4. Finished product protection: After fixation, avoid human damage and proceed to the next process in a timely manner

6、 Common problems and solutions

1. Hollow at the corner of the vagina

Reason: Uneven application or inadequate compaction of adhesive

Solution: Cut off the hollow area, re paste and fully compact it

2. Cracks at the corners

Reason: Stress concentration or material shrinkage

Solution: Add reinforcement layer and use elastic sealing material for treatment

3. Loose fixation

Reason: Improper selection of adhesive or inadequate base treatment

Solution: Clean the base layer, select suitable adhesives, and add mechanical fixation if necessary

7、 Safety precautions

1. Take safety protection measures when working at heights

2. Pay attention to insulation protection when using electric tools

3. Maintain good ventilation during the construction of chemical adhesives

4. Prevent burns and fires during hot melt construction

Conclusion

The fixing of the inner corner of the waterproof backing board is a key process in waterproof engineering, which requires construction personnel to master professional fixing techniques and rich practical experience. Only through scientific construction methods, strict quality control, and meticulous node processing can the integrity and durability of the waterproof system be ensured, providing reliable waterproof protection for buildings. In practical engineering, suitable internal corner fixing methods should be selected based on specific engineering conditions, material characteristics, and design requirements, and experience should be continuously summarized to improve construction quality.