Mapei Planiseal 88 Grey Osmotic Waterproofing Cement 20kg — Foundation, Tank & Concrete Waterproofing

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

• Foundations, footings & ground beams
• Basements & lift pits
• Retaining & perimeter walls
• Drinking-water & storage tanks
• Swimming pools & ornamental ponds
• Septic tanks & manholes
• Drainage channels & canals
• Inside and outside faces of concrete and blockwork

How to Use — Step-by-Step

Step 1 — Prepare the surface. Make sure it is sound, clean and rough. Remove dust, oil, grease, paint, laitance and loose material by mechanical brushing, grinding or high-pressure water. Repair cracks and honeycombing first.

Step 2 — Saturate with water. Thoroughly wet the surface until damp with no standing pools ("saturated surface-dry"). A dry substrate weakens the bond and the osmotic reaction.

Step 3 — Mix. Pour clean water first, then add the powder gradually while mixing with a low-speed drill and paddle — about 4.2–4.6 L per 20 kg bag. Mix 2–3 minutes to a smooth, lump-free slurry. Only mix what you can use within 1 hour.

Step 4 — First coat. Apply evenly by brush, trowel or spray at ~1 mm, working it well into the surface.

Step 5 — Second (and third) coat. After 5–6 hours (max 24), apply the next coat with strokes at 90° to the first for full, pinhole-free cover. Add a third coat for higher water pressure. Build to 2–3 mm total.

Step 6 — Cure and protect. Shield from sun, wind and rain for 24 hours; mist lightly with water in hot weather. Allow 7 days before backfilling, tiling, filling tanks or drinking-water contact.

Coverage guide: at 2 mm (~3 kg/m²) a 20 kg bag covers ≈ 6–7 m²; at 3 mm (~4.5 kg/m²) ≈ 4–4.5 m².

Important Information

• Do not apply in temperatures below +5 °C or above +35 °C, in direct hot sun, on frozen substrates, or when rain or frost is expected within 24 hours.
• Always pre-wet the substrate — never apply to a dry surface.
• Respect the 1-hour pot life. Do not re-temper (add more water) once the mix starts to stiffen; discard and mix fresh.
• Not a crack-bridging membrane on its own. For structures with movement or active cracking, reinforce corners/joints with mesh or pair with a flexible membrane.
• Wait 7 full days before filling potable-water tanks; rinse the tank before first use.
• Protect fresh coats from rain, sun and wind, and moist-cure in hot/windy conditions to prevent cracking.
• Safety: contains cement — wear gloves and eye protection; the wet mix is alkaline and can irritate skin and eyes. Keep away from children. Refer to the Mapei Safety Data Sheet.
• Store in a dry place; use within 12 months. Confirm details against the current Mapei Technical Data Sheet for your specific job.

FREQUENTLY ASKED QUESTIONS 

Q: What is Mapei Planiseal 88 used for? A: It is an osmotic cementitious mortar used to waterproof foundations, basements, retaining walls, water tanks, swimming pools and concrete/masonry structures against water penetration, including under pressure.

Q: Is Planiseal 88 safe for drinking water tanks? A: Yes. Planiseal 88 is certified for contact with potable (drinking) water, and can be filled after 7 days of curing.

Q: How much water do I add to Planiseal 88? A: About 4.2–4.6 litres of clean water per 20 kg bag (21–23% by weight), mixed to a smooth, brushable slurry.

Q: How many coats of Planiseal 88 do I need? A: 2–3 coats to reach a total thickness of 2–3 mm, with 5–6 hours between coats.

Q: What is the coverage of a 20 kg bag? A: Approximately 1.5 kg/m² per mm of thickness — roughly 6–7 m² at 2 mm, or 4–4.5 m² at 3 mm.

Q: Was Planiseal 88 previously called something else? A: Yes — it was formerly sold as Idrosilex Pronto.

Q: Where can I buy Mapei Planiseal 88 in Kenya? A: At Shabbiri Hardware, Magadi Road, Ongata Rongai and Tuala (past Nazarene University). Call 0741 042484 or 0745 554008.

STORE & DELIVERY INFORMATION

Main Branch: Magadi Road, Ongata Rongai, Nairobi

Tuala Branch: Past Nazarene University, Tuala

Call / WhatsApp: 0745 554008 / 0741 042484

Email: info@shabbirihardware.co.ke

Store Address: Magadi Rd, Ongata Rongai, Kenya

 Countrywide Delivery Available

•  Same-day delivery within Nairobi
•  Next-day delivery to other towns across Kenya

Delivery Locations: Nairobi, Mombasa, Nakuru, Kisumu, Eldoret, Thika, Naivasha, Kakamega, Bungoma, Kericho, Kitale, Machakos, Meru, Embu, Isiolo, Nanyuki, Malindi, Voi, Garissa, and more.