Waterproofing in Kenya (2026): Roof Slabs, Bathrooms, Tanks and Waterproof Cement

Water is the main enemy of concrete and plaster. A flat roof that leaks, a shower that wets the next room or a basement wall that weeps all come from water getting through. Waterproofing is cheapest when done during building, but most problems can be fixed later.

Where Do You Need Waterproofing?

Waterproofing Materials on Buy More Mall

Some photos are reference images of the product type, used under open licences. Image credits are on each product page.

How to Waterproof a Bathroom

1. Remove loose plaster and clean the surface; fill cracks.
2. Seal pipe entries and the wall–floor joints first.
3. Apply waterproof render or coating on the floor and up the walls (full height in the shower, at least 150 mm elsewhere).
4. Let each coat cure as the product instructions say.
5. Fill the floor with water for 24 hours to test before tiling.
6. Tile, then seal around the shower tray, taps and drain with silicone.

How to Waterproof a Flat Roof Slab

1. Clear the slab and check drainage outlets are open.
2. Repair cracks and holes.
3. Lay a screed so water runs to the outlets (no ponding).
4. Apply the waterproof coating or membrane in the recommended coats, turning it up the parapet walls.
5. Protect it from foot traffic and check it each year before the rains.

What Does Waterproofing Cost?

Cost depends on the area in square metres, the condition of the surface, the method and labour. Small bathroom jobs are mainly labour and a few bags of material; large roof slabs need more material and preparation. Measure the area and get a written quote. See also damp walls and rising damp and DPM and polythene prices.

Cost ranges are rough planning estimates for 2026 and vary by county, materials and labour; get a written quote.

Worked Example: Shower Wetting the Bedroom Wall

In a two-bedroom flat the wall behind the shower stays damp and the paint peels in the bedroom. The tiles are lifted, the wall and floor are coated with waterproof render up to ceiling height in the shower area, pipe entries are sealed, the floor is flood-tested for 24 hours, then re-tiled and sealed. The bedroom wall dries out over the following weeks and is repainted.

Common Mistakes to Avoid

• Painting a "waterproof paint" over a leaking slab without fixing ponding.
• Skipping the flood test before tiling.
• Leaving pipe entries and corners unsealed.
• Applying coatings on dusty or wet surfaces.

Not sure which one fits? Send us your details on WhatsApp or through the product page and we will help you choose.

Frequently Asked Questions

What is the best waterproofing for a concrete roof in Kenya?

A proper membrane or coating over a screed laid to falls, so water drains away instead of ponding.

Does waterproof cement stop leaks?

It reduces water passing through renders and screeds; active leaks and cracks must be repaired first.

How do I waterproof a bathroom before tiling?

Coat the floor and walls with waterproofing, seal joints and pipes, flood-test, then tile.

What is DPM used for?

It is laid under ground-floor slabs to stop ground moisture rising.

How often should a flat roof be checked?

At least once a year, before the long rains.

Prices shown are regular prices on Buy More Mall. Many products are currently on offer, so open the product page to see today's price.

Related Guides

• Damp Walls and Rising Damp
• How to Fix a Leaking Roof
• Cement Price in Kenya