Geosynthetic Clay Liner Construction Guideline
In construction projects, waterproofing is always a key step. Geosynthetic Clay Liner (also named GCL orBentonite waterproof blankets), which is known for their self-healing ability and reliable performance, are becoming more and more popular in modern engineering. This guideline will break down what this material is all about and how to install it properly.
Product Overview
The core material of a waterproof blanket is natural sodium bentonite. This special clay has a few impressive features:
1. Water swelling: When it meets water, it expands 10 to 16 times its original volume, forming a dense, gel-like waterproof layer.
2. Self-healing: If the blanket is slightly damaged, the nearby bentonite will expand when wet and fill the cracks automatically.
3. Eco-friendly: It’s made from natural minerals, so it’s safe for the environment.
Installation Steps
1. Laying the Blanket
- Direction matters: The fabric side should face the base surface, and the film side should face the water.
- Leave some slack: Keep it naturally loose with about 1–2% extra length to handle expansion.
- Proper overlap:
- Non-film type: overlap width should be about 200–300 mm.
- Film type: overlap width should be at least 100 mm, and seal the joints with mastic.
2. Fixing Methods
- Flat surfaces: Use cement nails and washers, spacing them no more than 500 mm apart.
- Vertical surfaces: Nail spacing should be 300–500 mm, and always work from top to bottom.
- Special areas: Reinforce fixing at the top and bottom edges.
3. Joint Sealing (The Most Important Step)
- Non-film type: Spread bentonite waterproof powder along the seam—about 100 mm wide and 5 mm thick.
- Film type: In addition to the powder, apply mastic for a double seal.
- Damage repair: Cover damaged areas with a new blanket patch extending at least 300 mm beyond the break.
4. Edge Treatment and Protection
- Edges: Roll the end into a pre-dug groove, seal it with mastic, and press firmly.
- Protection: Within 48 hours after inspection, pour the protective concrete layer to avoid long exposure.
5. Typical Applications
Bentonite waterproof blankets are widely used in:
- Underground projects: basements, subways, tunnels.
- Municipal works: landfills, artificial lakes, reservoirs.
- Building construction: as an additional waterproof layer for roofs.
Construction Tips
- Hire professionals: Experienced crews know how to handle tricky details like surface prep and joint sealing.
- Mind the details: Small things—like seams and edges—decide the overall waterproofing quality.
- Protect early: Don’t leave the blanket exposed too long; the protective layer should go on as soon as possible.
With its natural self-repair function and stable waterproof performance, the Geosynthetic Clay Liner is becoming a major choice in modern waterproofing projects. Follow the right installation steps and pay attention to the details—you’ll get the most out of what this material has to offer.
Contact us for quotation!
Sichuan Zhonglong Environmental Protection Co., Ltd.
📞Tel: +86 173 8021 9980
📬Email: sichuanzhonglong@163.com
🌐Website: https://www.zhonglonggeo.com
🎬Youtube: https://youtube.com/@zhonglonggeo