How to specify an exterior coating system for Bangladesh's climate

Step-by-step procedure

1. 1

   Survey the exposure

   Record orientation, rain-driven elevations, shading, proximity to the coast or industry, and pollution load. A south-west monsoon-facing wall in Chattogram is a different specification from a shaded inner courtyard in Dhaka.

2. 2

   Identify the substrate

   Confirm whether you are coating fresh render, existing paint, exposed concrete, AAC block or an insulation basecoat. Each dictates a different primer and often a different film build.

3. 3

   Set the performance targets

   Aim for low liquid water absorption combined with high water-vapour permeability so trapped moisture can escape. Add crack-bridging where hairline movement is expected.

4. 4

   Choose the binder

   Pure acrylic for general exposure and best value; silicone-modified for self-cleaning and heavy rain exposure; elastomeric where crack bridging dominates. Match the topcoat chemistry to the basecoat.

5. 5

   Choose the colour realistically

   Prefer inorganic pigments and light to mid tones on high-UV elevations. Deep saturated colours fade faster and run hotter, increasing thermal movement.

6. 6

   Build a sample panel

   Apply the full system on at least 2 m² of the actual facade, view it in morning and afternoon light, and get written client approval before mass application.

7. 7

   Write the maintenance cycle

   Issue the client a maintenance schedule: annual inspection, low-pressure wash every 2–3 years, sealant renewal at joints, and recoat interval for the chosen system.

Coastal and industrial exposure

Near the coast, salt-laden air accelerates chloride ingress and coating failure. Increase film build, tighten the recoat cycle, and pay particular attention to sealing exposed concrete edges and balcony soffits.