STP ShaliDrain 10F
STP’s HDPE dimpled drain board that shields waterproofing membranes from backfill damage and carries groundwater safely away from the structure.
What is it?
A 710 gsm HDPE dimpled sheet, 10 mm dimple height, factory-bonded to 110 GSM polypropylene geotextile fleece; supplied in 2.3 m x 20 m rolls.
Where is it used?
Basement and retaining walls, podium decks, terrace gardens, tunnel linings, underground parking, dam faces, and pipeline trenches — wherever a membrane needs protection and drainage.
Why use it?
Backfill punctures and abrades unprotected membranes; ShaliDrain 10F absorbs that damage while its 4.6 l/m²/s drain flow relieves hydrostatic pressure before it reaches the structure.
How is it applied?
Rolled out dimples-to-substrate, fleece facing the soil, with joints lapped 20-30 cm and sealed by hot-air welding or tape, then backfilled within 30 days.
About STP ShaliDrain 10F
ShaliDrain 10F is not a waterproofing membrane — it’s the layer that protects one. STP Limited manufactures it as an HDPE sheet embossed to a 10 mm dimple height and laminated at the factory with a 110 GSM polypropylene geotextile fleece. The dimpled core forms a continuous air gap and drainage channel against the structure, while the geotextile filters groundwater through and holds soil fines back, so the channel doesn’t silt shut. Sold in 2.3 m × 20 m rolls (about 46 m² each), it sits in STP’s Waterproofing range alongside the company’s membranes and coatings, meant to be used with them, not instead of them.
For Delhi NCR and most Indian metros, the case for a drainage composite comes down to site reality rather than exotic engineering. Basement excavations sit through monsoon water tables, backfill is rarely the clean aggregate a spec calls for, and compaction happens with whatever equipment is on site. A membrane applied directly against that backfill has a short life. ShaliDrain 10F goes between the two — membrane on the structure, board over the membrane, backfill against the board. STP benchmarks its compression, tensile, and flow properties against European geosynthetic standards (EN 9864, EN 10319, EN 12958, EN ISO 11058/12956), the closest recognised third-party reference this product category has, since India has no dedicated IS specification for dimple drainage boards yet.
The technical insight
The number worth checking on the data sheet is drain flow capacity — 4.6 l/m²/s (EN 12958) — which determines whether the board can actually carry away site groundwater; the taller-dimpled ShaliDrain 12F trades some flexibility for a larger air-gap volume and higher flow on aggressive water tables. The geotextile’s 95-micron opening size (EN ISO 12956) is the other detail worth confirming — fine enough to filter backfill soil at 120 mm/s permeability without clogging, so drainage keeps working years after installation. Compression strength of 230 kN/m² covers standard backfill and podium loading, but deep excavations or heavier surcharge should be checked against actual site loads, not assumed.
Where it is used
- Basement and retaining wall membrane protection before backfill
- Podium decks and terrace/roof garden drainage layers
- Metro, rail, and road tunnel lining drainage
- Underground and multi-level basement car parks
- Raft foundations, as a moisture barrier in place of lean concrete blinding
- Dam faces, reservoir walls, water-retaining structures
- Pipeline trenches and underground utility corridors
- Swimming pool and water tank exterior drainage
Key advantages
- Absorbs backfill impact and abrasion instead of the membrane underneath
- 230 kN/m² compression strength handles standard backfill and podium loads
- 4.6 l/m²/s drain flow actively relieves hydrostatic pressure
- 95-micron geotextile filters soil fines so drainage doesn’t silt up
- Resists acids, alkalis, solvents, and plant root penetration
- Rated -30°C to +80°C and drinking-water safe
- Lightweight, flexible rolls install faster than rigid boards on irregular walls
- STP rates correct installations for 25+ years service life
Limitations & considerations
- Protects and drains — it doesn’t waterproof on its own; a membrane is still required
- UV exposure capped at 30 days before it must be covered
- Reaction-to-fire Class E — not a fire-rated product
- Drainage only works if overlaps are correctly lapped and sealed
- Very high water tables may call for the taller ShaliDrain 12F instead
- Full-width rolls need level, dry, covered storage on site
Selection & best practice
Lay ShaliDrain 10F dimples-to-substrate and fleece facing the soil — that’s what lets the geotextile filter properly instead of getting buried against the wall. Keep overlaps to a genuine 20 cm minimum vertically and 30 cm horizontally, welded or taped rather than just butted. Don’t leave the board exposed beyond its rated 30 days before backfilling, and confirm the waterproofing membrane underneath has cured and been inspected first — once backfill goes in, it’s no longer accessible for repair.
Specifications
| Product Type | HDPE Dimpled Drain Board with Fleece |
| Dimple Height | 10 mm (EN 9863-1) |
| Total Weight | 710 gm/m² (EN 9864) |
| Geotextile | 110 GSM polypropylene fleece |
| Compression Strength | 230 kN/m² |
| Tensile Strength (MD/CMD) | 8 ± 1.6 kN/m / 6 ± 1.2 kN/m (EN 10319) |
| Drain Flow Capacity | 4.6 l/m²/s (EN 12958) |
| Water Permeability | 120 mm/s (EN ISO 11058) |
| Pack Size | 2.3 m width × 20 m length rolls (~46 m²/roll) |
Industry use cases
Residential & Commercial Basements
Delhi NCR builders lay it over the retaining-wall membrane before backfilling, so the membrane survives contact with soil and debris.
Metro & Rail Infrastructure
Used behind tunnel linings and diaphragm walls to drain seepage and protect the waterproofing system from groundwater pressure.
Podiums & Terrace Gardens
Installed under planters and landscaped decks so irrigation water drains away instead of pooling against the membrane.
Underground Parking
Wraps basement car-park walls, pairing membrane protection with continuous drainage to reduce dewatering-pump load.
Dams & Water-Retaining Structures
Applied to dam faces and reservoir walls where chemical resistance and drinking-water approval matter alongside drainage.
Frequently asked questions
Does ShaliDrain 10F waterproof the wall by itself?
Which side faces the wall — dimples or fleece?
How much overlap do joints need?
What’s the difference between ShaliDrain 8F, 10F, and 12F?
How long can it stay exposed before backfilling?
How much does one roll cover?
How we position STP ShaliDrain 10F
Within STP’s range, ShaliDrain 10F sits between the lighter ShaliDrain 8F and the taller-dimpled ShaliDrain 12F for higher water tables, with ShaliDrainCell 30 as the heavier-duty cellular option for deep podium drainage. It’s designed to pair with an STP waterproofing membrane on the same wall, not replace one. Fosroc doesn’t manufacture a directly equivalent HDPE dimple board — its below-grade range centres on membranes, coatings, and injection systems (Proofex, Brushbond) — so a mixed-brand specifier would typically pair a Fosroc membrane with a dimple board from a dedicated geosynthetics supplier rather than a like-for-like Fosroc product.
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