Repairs in new Construction: Waterproofing of ACP Roof Joints

Due to improper design or implementation sometimes Part of the New projects are re-executed or repaired. Islamabad - Rawalpindi BRTS (Bus Rapid transit System) Consisted of 20 Stations Covering around 23 km path connecting twin cities. Each station Roof Consisted of ACP Sheets Fixed on Aluminum Frame with Steel supports. The joints of ACP sheets were filled by Silicon but improper materiel and workmanship caused leakage in joints. Total length of joints was over 400,000 RFT. Leakage was invariably from almost every area. So in order to avoid hectic procedure of tracing the leakage all the joints needed treatment so a permanent solution could be established:

1. The low thickness and poorly bonded silicon was removed and replaced with Polyurethane sealant.
2. After filling the joints, they were allowed to cure for 6–7 days before water Pounding test was conducted.
3. All the joints were covered by 6 inches wide LAM (Liquid applied Membrane) Polyurethane based Waterproofing system UV Resistant in four steps:
   1. Grinding for paint removal;
   2. PU Primer;
   3. PU Flood Coat with Reinforcement Fabric;
   4. Top coat keeping aesthetics. 

Presentation Learning Objectives:

1. Unseen Challenges in new Construction
2. Waterproofing of Vibrating Roof Structure
3. Waterproofing with Aesthetics 
4. Working on operating stations with challenges like Rainy Season and Height