Mapei Planiseal 88 Grey Osmotic Waterproofing Cement 20kg — Foundation, Tank & Concrete Waterproofing
MAPEI · Trusted Waterproofing Since 1937
Mapei Planiseal 88 Grey Osmotic Waterproofing Mortar
One bag. Total protection. The crystalline cement coating that turns ordinary concrete into a permanent water barrier — trusted on foundations, tanks and pools nationwide.
Damp walls, leaking tanks and sweating basements all share one cause — water finding its way through porous concrete. Mapei Planiseal 88, the grey osmotic mortar formerly branded Idrosilex Pronto, solves that problem at the source. Mix it with clean water, brush it on, and its reactive minerals soak into the concrete and grow microscopic crystals that plug the capillaries from the inside out. The wall itself becomes the waterproofing layer — sealed for the life of the structure, resistant to standing water pressure, and effective whether the water pushes from the front or seeps from behind. It's rated for drinking-water tanks, easy enough for any mason to apply, and always on the shelf at Shabbiri Hardware, Ongata Rongai & Tuala.
What Makes It the Contractor's First Pick
🏠 Seals From the Foundation Up
Keeps groundwater and soil moisture out of footings, plinths and basement walls for good.
🚰 Fit for Drinking Water
Lines potable tanks and reservoirs safely once it has cured for a week.
🖌 One-Product Simplicity
No primers or extra layers — add water, then brush, trowel or spray two to three coats.
💪 A Bond That Lasts
Grips tightly to concrete and hardens above 25 MPa for years of reliable service.
Put It to Work On
Full Technical Data
Applying Planiseal 88 — 6 Easy Steps
Get the surface right. The substrate must be solid, clean and lightly textured. Clear off dust, grease, flaky paint and laitance, and make good any cracks or voids before you begin.
Wet it thoroughly. Douse the concrete with clean water so it is evenly damp — but not pooling. Dry concrete steals water from the mix and stops it curing properly.
Prepare the mix. Stir the powder into 4.2–4.6 litres of clean water per 20 kg bag using a slow drill and paddle until it is smooth and free of lumps. Mix only a batch you can finish inside an hour.
Lay coat one. Work an even 1 mm layer into the surface with a brush, trowel or spray, making sure it keys well into the concrete.
Follow with coat two. After 5–6 hours, brush the next layer at right angles to the first so no pinholes remain. Add a third coat where water pressure is high. Finish at a 2–3 mm total build.
Cure and protect. Shelter the coating from sun, wind and rain for the first 24 hours and mist it in the heat. Wait a full 7 days before backfilling, tiling or filling any tank.
💡 Handy estimate: one 20 kg bag covers roughly 6–7 m² at 2 mm, or about 4–4.5 m² at 3 mm.
Read This Before You Apply
- Hold off in temperatures below +5 °C or above +35 °C, under fierce sun, on frozen concrete, or if rain or frost is due within 24 hours.
- Always pre-soak the surface first — applying to dry concrete weakens both the grip and the crystallising action.
- Don't re-wet a batch that has begun to set. Discard it and mix fresh within the one-hour working time.
- As a rigid coating it doesn't bridge moving cracks on its own — reinforce those areas with mesh or a flexible membrane.
- Give a potable-water tank the full 7-day cure, then rinse it before filling for use.
- Being cement-based, wear gloves and eye protection; the alkaline wet mix can irritate skin and eyes, so keep it away from children.
- Keep bags dry and use within 12 months. For anything job-specific, refer to Mapei's current Technical Data Sheet.
Buy Mapei Planiseal 88 at Shabbiri Hardware
Genuine Mapei waterproofing products and building materials — right here in Rongai and Tuala.
📍 Magadi Road, Ongata Rongai • 📍 Tuala — Past Nazarene University
📞 0741 042484 | 0745 554008
Specifications
| Brand | Mapei |
| Model | MP88-25KG-GRY |
| Category | Waterproofing & Sealants |
| Availability | In stock |
| Sourced by | Shabbiri Hardware Kenya Limited |
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