Direct answer
Self-adhesive bitumen membrane (PetroSelfGrip) waterproofs bathrooms, terraces, and flame-restricted details without a propane torch. Peel the release film, position on primed dry concrete, roll laps, and turn sheets up walls to the specified height—then flood-test before tile. Choose 1.5mm for internal wet rooms under tile; 2mm for terraces and weather-exposed pods.
On whole-building envelopes, Petroseal typically pairs PetroSelfGrip wet pods with torch-applied PetroGrip APP or SBS on the main roof or basement field. Lahore contractors (Unicorn, Water Seal, Roof Power, and others) may install several membrane brands—require named gauge, upturn, primer, and flood-test holds, not a generic “chemical waterproofing” line item.
Specification starting points
| Condition | Thickness | Upturn / detail | Petroseal product |
|---|---|---|---|
| Internal bathroom / kitchen under tile | 1.5mm | ≥150mm walls; higher at showers | PetroSelfGrip |
| Terrace / weather-exposed wet area | 2mm | Parapet and threshold continuous pan | PetroSelfGrip |
| Lift pit / flame-restricted basement detail | 1.5–2mm | Lap to SBS field sheet | PetroSelfGrip + PetroGrip SBS |
| Main exposed roof field | Torch APP/SBS | — | PetroGrip APP (not self-adhesive alone) |
| Retrofit leak, no external access | Diagnose first | May need negative-side strategy | See positive vs negative-side guide |
When cold-applied membrane beats a torch on site
Open flame is restricted or unsafe in bathrooms, kitchens, stair landings, elevator machine rooms, and many hospital wards. PetroSelfGrip carries rubberized bitumen on the underside; the applicator peels, positions, and presses. Laps are rolled firm and sealed per detail.
Developers specify PetroSelfGrip for wet-area pods while keeping torch APP or SBS on the main roof. Petroseal manufactures both families in Lahore so one brand covers the envelope.
Thickness: 1.5mm vs 2mm
| Gauge | Typical use |
|---|---|
| 1.5mm | Internal wet rooms, utility areas, light detailing under tile |
| 2mm | Terraces, bathrooms with outdoor exposure, repair zones, pre-finish weathering |
On residential terraces, 2mm full-field sheets with upturns at parapets and door thresholds form a continuous pan when corners and pipe penetrations are patched from the same roll.
Substrate preparation
Bond strength depends on a clean, dry, sound substrate. New concrete should be cured and free of laitance; old slabs need grinding where paint, oil, or loose mortar exists. Do not stick membrane over standing water or green concrete—blistering follows within weeks.
Corners at wall-floor junctions should be coved or filleted before membrane so the sheet does not bridge a sharp ninety-degree angle under tension.
Bathrooms and wet rooms
Full-floor membrane under the tile bed, with sheets turned up at least 150mm on walls (higher at shower zones per consultant detail), contains migration water even when grout joints age. Partition walls between bathroom and bedroom should carry the membrane upturn on the wet side.
PetroSelfGrip has been used on institutional projects alongside torch membrane on main roofs—one manufacturer, mixed by zone. See /waterproofing/bathroom-wet-area and /systems/self-adhesive-membrane.
Terraces: slopes, upturns, and protection
Terraces need positive fall to drains before membrane. After membrane, use a compatible protection board or screed bed before porcelain or stone so construction carts do not puncture the sheet.
Where the terrace meets a torch-applied main roof, show a lap sequence in the drawing—bond PetroSelfGrip to PetroGrip torch membrane with primer and overlap width defined.
Storage and common mistakes
- Store rolls in shade; heat softens adhesive and makes release film harder to strip.
- Do not stop membrane at the shower curb—continue under benches and curbs.
- Roll lap pressure at seams; avoid generic tape instead of proper overlaps.
- Keep PetroGrip/PetroSelfGrip through the stack for primer compatibility at transitions.
- Do not treat self-adhesive bathroom membrane as a full basement tanking substitute under high hydrostatic head.
For submittals and pairing with APP or SBS on the same project, contact Petroseal at 0321 8489737 or petrosealenterprises.com.