Scope of work: Waterproofing of swimming pool using SikaTop Seal 107 underneath tiling works
1. System Build-up
Waterproofing compounds are not designed to bear heavy load. Hence, no thick build-up such as screed or levelling render shall be applied over them. Typical build-up shall then be as follow:
• Substrate
• Levelling screed/render (if required)
• Waterproofing compound
• Tile adhesive
• Tile
2. Key Issues
2.1. Surface preparation
Prepare and clean concrete surfaces by suitable mechanical means such as abrasive blast cleaning or equivalent to ensure cement laitance, surface contamination (e.g. curing compound) and all existing coatings are removed. The resultant surface finish shall be profiled for maximum bond.
2.2. Levelling Mortar/Screed
When required to provide a smooth and level surface, levelling screed or render shall be placed before the application of the waterproofing compound. The preparation and application of these levelling compounds shall be performed according to the state of the art. In particular, if required to improve adhesion, a bonding bridge using SikaLatex shall be used. Typical design of such bonding bridge slurry is:
SikaLatex: Water 1: 1 part by volume
Cement: Sand (0-1mm) 1: 1 part by volume
Mix the dry cement sand to gauging SikaLatex solution until brushable consistency. Apply the bonding bridge using a stiff brush or by mechanical spray. Work well the slurry onto the substrate. Subsequent application (levelling screed/render) shall be carried out while the bonding bridge is still tacky – wet on wet.
After placing the levelling screed/render, cure properly the freshly placed mortar with wet hessian. Do not use curing compound as this might result in adhesion failure of the waterproofing compound. Maintain the wet curing for a period of at least 7 days.
2.3. SikaTop Seal 107
2.3.1. Application conditions:
Substrate and ambient temperature shall be higher than +8°C and lower than 35°C at the time of application. Application shall not be carried out in direct sun and/or strong wind or when rain is expected.
2.3.2. Mixing ratio:
Used as slurry: A: B = 1: 4 (parts by weight)
Used as mortar: A: B 1: 4.5 ( parts by weight)
2.3.3. Mixing:
SikaTop Seal-107 must be mechanically mixed using a forced action mixer or in a clean drum using a drill and paddle (max. 500 rpm). A normal concrete free fall mixer is NOT suitable. Shake part A before using it. Pour approximately half of part A into the mixing container and add part B slowly while mixing. Add the remainder of part A and continue mixing until a uniform lump free consistency is achieved. The surface must be pre-wetted to a saturated surface dry condition before application.
2.3.4. Application:
- As a slurry:
Apply the mixed SikaTop® Seal 107 either mechanically, by spray or by hand using a stiff brush. Apply in the same direction. Apply the 2nd coat of SikaTop® Seal-107, applied by brush in crosswise direction to the first application as soon as first coat has hardened.
- As a mortar:
When SikaTop® Seal-107 is applied by trowel (e.g. for a smooth surface finish), the product must be mixed with a 10% reduction of part A (~ 1A: 4.5B). Apply the 2nd coat of SikaTop® Seal-107 as soon as the first coat has hardened. For pore/blowhole filling, tightly trowel into the pores/ blowholes of the surface.
2.3.5. Waiting time between coats:
The second coat shall be applied when its application does not disturb the first layer. As a rule of thumb, when the first coat is hard to the fingernail, the second coat can then be applied. The time required depends not only on the temperature but as well as on humidity level and ventilation. As a guide the following waiting time can be taken:
+10°C ~12 hours
+20°C ~6 hours
+30°C ~3 hours
If waiting time is within the indicated period, it is not necessary to pre-dampen the surface. However, if the waiting period exceeds 24 hours, lightly blast-clean and pre-dampen the surface.
2.3.6. Curing:
It is essential to cure SikaTop® Seal-107 immediately after application for a minimum of 3 to 5 days to ensure full cement hydration and to minimise cracking. Use polythene sheeting or similar approved methods. Further treatment (e.g. tiling works) shall be carried out after a waiting period of at least 7 days at 20°C.
2.3.7. Consumption:
As a guide, ~2,0 kg/m²/mm (excluding allowance for wastage, surface profile and porosity, etc…).
2.3.8. Application thickness
For waterproofing application, always use at least 2 coats to give a total thickness of between 1.5 to 2mm. In area of high water head, 3 coats may be required.
2.3.9. Note:
For more detailed information, refer to the most recent technical data sheet.
2.4. Tiling works
If required, tiling works shall proceed using tile adhesives that are suitable for pool application e.g. Class C2ET of EN 12004 or relevant local standards . Example of Sika cement based tile adhesives are: Sika Ceram-205, Sika Ceram-253 etc… Tiling works shall be carried out according to the latest state of the art.
2.5. Detailing
Generally, failures in waterproofing system occur at details such pipe penetration, anchor, gully etc… So a particular attention shall be given and guideline provided in the enclosed drawings shall be followed.
2.6. Safety
As cement is alkaline and may cause irritation to certain allergic people, applicators are recommended to wear gloves and goggles while working with products containing cement. In case material gets into eyes, wash immediately with clean water. If irritation persists, seek medical assistance. For more information, please refer to the relevant Material Safety Data Sheets.
