Types of Waterproofing in G.I Corrugated Sheet

Waterproofing Sheet: Do you prefer a low-maintenance roof that can prove as a strong barrier to moisture, heat, and other elements? Opt for GI (galvanized iron) sheet today.

Iron is a hard substance that exists in four distinct crystalline forms. When heated, it can be shaped into materials with varying characteristics. Apart from its physical presence, iron is found in the human body for growth and development. However, it has some drawbacks: This element forms a layer of oxide called ’rust’ in damp conditions.

To overcome the issue, different methods are applied on the product to enhance its life and usefulness. Some of the most common ones include paint, oiling, powder coating, and galvanizing. Some users apply dual coatings for better results.

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Waterproofing GI Corrugated Sheets

Galvanized roofs are susceptible to damage because of leaks and severe weather conditions. If your roof structure needs a repair, contact Lakhwa Chemical Services today!


Following are some essentials needed for G.I waterproofing sheet:

  • Powerwasher
  • Power screwdriver with bits
  • Brush, roller, or spray gun
  • Liquid Rubber (seam-type)
  • Liquid Rubber Waterproof Sealant


Before working on the GI roof, inspect the fasteners. Over time, these accessories can get loose and create problems during work. Tighten the fasteners and wash the roof to commence work.


To waterproof a GI sheet, it is essential to clear the rust or particulates present. Most experts use the ‘Abrasive Blast Cleaning Method’. However, the process is not practical for large-sized sheets. Various chemicals or solutions can be applied instead.

Use liquid rubber seam tape to seal cracks or seams more than 1/8th inch long. Press and hold the tape for 30 seconds to develop a strong bond. Metal-bonding caulking can also be used to fill smaller seams or cracks. The drying time is an important aspect in the process. The seam tape and caulking takes 60 minutes and 2 hours respectively.

Ensure that the GI sheet is free from oil, grease, and other contaminants. Use high pressure water to remove glued debris or flaking rust. If the sheet is not leak-proof, use 20cm wide roof fleece. After applying, brush the area with a single coat of anti-corrosion or waterproofing chemical.

Application of Primer

Most GI roof sheets require one or two coats of primer before the application of intermediate and top coats. Sufficient time must be maintained between the coat applications. Priming is necessary before waterproofing galvanized iron to ensure proper adhesion and quick drying.

Sealing and Waterproofing

There are several methods to ensure a crystal-clear coat. Most experts use airless spray technology for a quick result. Others use brush and rollers. However, care should be taken about the dry film thickness of the coat; it should be 175 microns. Mask the entire area (not to be painted) with non-adhesive tape and protect sensitive items, such as glass from paint spills or over spraying.

Elastomeric rubberized paint is the best waterproofing chemical for GI sheets. Following are some factors that should be managed by waterproofing experts:

  • Temperature range: 12 to 25c
  • Humidity: 80%
  • Dilution: 3% by volume with water

Two coats of elastomeric paint should be applied at an interval of 3-6 hours. Ensure that the paint offers high SRI (solar reflective index), strong UV resistance, and flexibility.

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Galvanized corrugated iron sheet offer several advantages for users. It is one of the most sought-after roofing materials for users. Besides commercial, industrial, and agricultural purposes, it is used for residential roofing, fencing, and partitioning.

Corrugated GI waterproofing sheet are available in different specifications in the local market. Their lightweight nature helps reduce the load on structures. Moreover, these sheets are fire-resistant, long-lasting, and low-maintenance. If you are constructing a new home, reconditioning an existing structure, or replacing your roof, GI corrugated sheets is one of the most beneficial options.

To evade leakage and water ingress, have your GI sheets waterproofed by Lakhwa Chemical Services today!

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