Direct answer
Climate drives modifier choice by plane: exposed horizontal roofs in Punjab and Sindh need heat-stable APP cap sheets (PetroGrip APP with aluminum or granular surfacing) because sustained UV and temperature swing stress plain bitumen films. Below-grade walls and rafts face groundwater and structural movement—PetroGrip SBS provides the flexibility and lap integrity those planes need.
Monsoon season increases hydrostatic head against basements; it does not change APP into an below-grade default. Competitors marketing one membrane type nationwide ignore that split—Petroseal documents both on separate system pages.
Climate-linked specification
| Exposure | Climate stress | Petroseal starting point |
|---|---|---|
| Exposed flat roof Lahore | UV, high deck temperature | PetroGrip APP 4mm cap |
| Basement Lahore / high table | Monsoon head, movement | PetroGrip SBS; double-layer if critical |
| Podium planter | Root moisture + movement | PetroGrip SBS primary |
| Industrial roof traffic | Mechanical + heat | APP cap + protection or pavers |
| Split slab occupied below | Movement + leak risk | SBS structural plane |
Manufacturer landscape
Roofline, Grace Chemicals, Petroseal, and imported rolls all appear on Pakistani roofs. Climate-appropriate spec means APP/SBS call and surfacing on each ply—Petroseal PetroGrip is manufactured locally with batch marking for submittal match. Importers may suit consultant-named global products; domestic manufacturers suit lead time and Lahore site support.
Cross-reference
For modifier chemistry detail, lap checklists, and FAQs, read the main APP vs SBS PetroGrip guide. Link /waterproofing/lahore and /waterproofing/roof from consultant specs for application context.