The most trusted solution to prevent any damp seeping through your roof floors is to waterproof your roof with Sika’s universal waterproofer and bonding agent, Cemflex®. Cemflex® mixed with Portland cement and water forms an effective waterproofing slurry that is used in conjunction with the Cemflex® Fiber. Cemflex® can also be applied to waterproof Reservoirs, Balconies, Verandas, Fish Ponds and Retaining Walls.
What you will need
- Cemflex®
- Cemflex® Fabric
- Portland Cement
- Water
- Wire brush
- Block brush / large paint brush
- Bucket to mix
- Gloves
- Mask
- Spatula (small quantities) / mechanical mixer and paddle (quantities exceeding 5l).
Product Information
Step 1
Prepare the concrete roof by cleaning it from debris and making sure that it is free of any dust or loose material. The concrete roof can be cleaned using a wire brush and broom.
Step 2
Prepare the Cemflex® Fabric and the Sika® Cemflex® liquid for the required area.
In order to prepare the waterproofing slurry, you will need to mix 1 liter of Sika® Cemflex®, 1 liter of water and 3.4 kg of Portland cement, which will yield 3.2 liters of waterproofing slurry that will cover an area of 1m² with Cemflex® Fabric.
First mix the required amount of Cemflex® and water and then add the correct amount of Portland cement slowly, while mixing, to avoid any formation of lumps. You will now have a Cemflex® slurry that is ready to be applied.
For more mixing instructions and application process please Refer to the Cemflex® Product data sheet.
Step 3
Dampen down the the floor that you will be applying the product to and make sure that there is no standing water. Ensure that roof is thoroughly saturated and while the surface is still damp apply a coat of the Cemflex® slurry.
Dunk the Cemflex® Fiber in the Cemflex® slurry until the membrane is fully saturated.
Remove the soaked membrane from the slurry and lightly squeeze before placing the Cemflex® membrane over the damp substrate with your gloved hand, smoothing off with the brush to eliminate all air bubbles. Overlaps of adjacent fabric must be a minimum of 50mm.
Step 4
Once the entire area is covered and all the air bubbles have been removed, apply a generous coat of the slurry and allow to dry for 24 hours.
Step 5
After waiting 24 hours, mix a new batch of the Cemflex® slurry and apply the final coat to the completed area. Allow the final coat to dry for 6 to 8 hours before applying tiles on the surface. Freshly applied Cemflex® should be protected from damp, condensation and water for at least 12 hours.