Rising damp and why bitumen DPC still matters
Rising damp is capillary suction of groundwater and soil moisture up masonry walls—visible as tide marks, flaking paint, salt efflorescence, and musty ground-floor rooms. A continuous damp proof course (DPC) at the plinth interrupts the path when installed correctly. PetroDPC bitumen membrane rolls from Petroseal Enterprises are self-adhesive sheets designed for peel-and-stick placement in mortar beds without a propane torch.
A torn plastic DPC or a missing course at one bay is enough for years of damage. Specifying a manufactured bitumen DPC with controlled width and 15m roll length reduces patchwork failures common with ad hoc site-cut materials.
Roll sizes: 4.5", 9", 13", and 15m length
| Width | Typical application |
|---|---|
| 4.5" | Single-leaf walls, partition damp barriers |
| 9" | Standard nine-inch cavity and solid walls |
| 13" | Wider block courses, thicker plinth beams |
| 15m roll length | Continuous runs with fewer end joints along street fronts |
Choose width to match one or two block courses so the DPC spans the wall thickness with planned laps at corners and piers—each lap is an inspection point.
Installation at plinth level
- Install on a level, dry course per structural drawing.
- Remove dust and protruding mortar tails before bonding.
- Press continuously; do not bridge voids over honeycombed block.
- Lap corners by at least 100mm; roller-press overlaps.
- Collar penetrations with compatible sealant before the next lift.
Where DPC meets vertical rising wall membrane or horizontal podium waterproofing, show a lap detail so systems connect without a gap at the inside corner.
DPC versus roof membrane
DPC rolls are not roof cap sheets. They are width-optimized barriers for masonry capillary rise, not for permanent ponding water or UV exposure. For horizontal waterproofing at grade, use PetroGrip torch or PetroSelfGrip roof-grade sheets per the structural detail.
Inspection checklist
- Verify width submittal against block schedule before masonry starts.
- Photograph continuous runs and corner laps before concealment.
- Reject courses laid on mud or standing water.
- Repair tie holes and chases that slice the DPC line.
PetroDPC is Made in Pakistan by Petroseal Enterprises alongside APP, SBS, and PetroSelfGrip roof membranes. Measure external wall length, add lap allowances, and call 0321 8489737 for quantity take-offs before masonry mobilization.