Metal Sheet Roof Waterproofing in Karachi
Seamless coating for corrugated, galvanised and shed roofs including screw heads, laps and ridges.
Metal sheet roofs on factories, sheds, hangars and godowns leak mostly at screw heads, overlaps and ridge lines. Replacing the sheets is expensive, so we restore the roof with a seamless coating that seals every weak point.
Problem: why metal sheet roof waterproofing is needed
Thermal expansion loosens screws and washers. Rust forms at laps and the sheet slowly corrodes. Rain then enters through fasteners and overlaps, damaging stored goods and equipment.
- Dripping near screws and overlaps
- Rust spots and flaking paint on the sheets
- Condensation and drips under the roof on cool mornings
- Very hot interior under metal sheets
Our solution
We remove rust, treat the metal, seal each fastener and overlap with reinforcing mesh and mastic, and apply a flexible elastomeric coating that adds waterproofing and reflects heat.
Waterproofing methods used in Pakistan
Elastomeric coating with fabric reinforcement
Stretchable coating with polyester strips at laps and ridge for long lasting sealing.
Rust converter and anti-corrosive primer
Stops corrosion before the coating is applied so rust does not return under the membrane.
Polyurethane coating
High build coating with strong adhesion on metal for demanding industrial roofs.
Reflective white topcoat
Reduces heat gain inside sheds and warehouses.
Application process: how we work
- Inspect sheets, screws, laps and gutters
- Mechanical cleaning and rust removal
- Tighten or replace fasteners
- Anti-corrosive primer on bare metal
- Seal laps, screw heads and ridges with mesh and mastic
- Apply two coats of elastomeric membrane and finish with reflective top coat
Why choose Royal Chemical Service
- ISO certified quality management
- Trusted by well known Pakistani brands, banks and hospitals
- Free site inspection and clear written quotation
- Trained application team with proper surface preparation
- Quality materials and a tested, handed-over finish
Frequently asked questions
Can an old rusted metal roof be waterproofed?
Yes, if the sheet is structurally sound. Heavily corroded sheets are replaced locally before coating.
Will the coating peel off the metal?
Not when the surface is cleaned and primed correctly. Preparation is the most important step.
Can work be done while the factory is running?
Yes, since work is on the outside of the roof we normally do not stop your operations.
Does it reduce noise and heat?
The coating lowers heat gain, and also reduces rain drumming noise slightly.
Get a free inspection and quotation
Tell us what you need. We reply the same day during working hours.