Mega Engineering : Industrial Warehouse Waterproofing

Project Overview

62,000 sq ft across the roof and sidewall perimeter of a Mega Engineering industrial warehouse in Sangareddy.

Industrial waterproofing is different from residential and commercial in one critical way: the roof is a working surface. Forklifts cross it for maintenance access. HVAC units and exhaust systems are mounted on it. Water storage tanks sit on it. The waterproofing system must handle concentrated point loads, chemical exposure from industrial exhaust, and surface temperatures that routinely exceed 65°C in Telangana's summer.

The work was executed during active production operations. Warehouse shutdown was not an option. Crew access to the roof was managed in coordination with Mega Engineering's plant manager to avoid conflict with in-building crane operations and shift changeovers.

Substrate Condition at Intake

The original roof was a corrugated metal sheet structure with a concrete screed overlay applied in 2015. The screed had developed significant cracking — the thermal cycling on a metal-substrate roof is substantially higher than on a concrete flat roof, and standard cementitious screed cannot accommodate this movement indefinitely.

Water ingress was active at 9 locations, all tracing to screed cracks. Three locations had corrosion staining on the structural steel below, indicating water had been tracking through for at least two monsoon seasons.

The sidewall perimeter showed efflorescence and moisture migration at the wall-to-slab junction at four corners.

Method Selection Rationale

APP-modified bituminous membrane was specified for the roof system. APP (Atactic Polypropylene) modification gives bituminous membrane its key property for industrial roofs: high softening point. Standard bituminous membrane softens and deforms under direct sun at the temperatures reached on an industrial metal-substrate roof in Telangana. APP-modified membrane retains dimensional stability up to 130°C. This is the correct system for industrial and high-temperature roof applications. It is not the correct system for residential terraces that will be tiled or used as usable floor space — but for this application, it was the right choice.

The sidewall perimeter received an SBR-modified cementitious system — a different specification from the roof. System selection should match substrate and exposure conditions. Using a single system across all surfaces on a project is a mark of cost-cutting, not expertise.

Execution Highlights

The live production constraint required a detailed daily work plan shared with the plant manager each morning. Roof access was divided into six zones. At any time, a maximum of two zones were active. The remaining four zones remained accessible for plant maintenance as normal.

Structural steel inspection at the three corrosion locations identified one column that required a mechanical repair by Mega Engineering's structural team before waterproofing could proceed. This was flagged at the end of Week 1, addressed by Week 3, and did not affect the overall delivery schedule.

A critical detail on industrial warehouses is the parapet-to-gutter junction. Industrial roofs drain via internal box gutters or external gutter channels, not into conventional drainage outlets. The junction between the waterproofing membrane and the gutter system requires a custom flashing detail. Four custom flashings were fabricated on site and integrated into the membrane system.

Post-Handover

5-year written warranty issued covering the roof membrane system. The sidewall cementitious treatment is covered under the same document with separate clause terms reflecting the different exposure conditions.

One post-monsoon site visit completed, October 2023. No leak complaints. The three corrosion locations confirmed dry.

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Project commissioned by Mega Engineering for their Sangareddy industrial facility. Technical specification and site supervision by Subhash Chander, Victoria Waterproofing.