My car porch concrete flat roof has crack and it is leaking, how do I fix it?

Fixing crack with Sikadur®-20 Crack Seal

  1. Slightly widen and increase the surface on the existing cracks.
  2. Remove dit and dust from the cracks.
  3. Mixing: Pour component A & B into the bottle with 1:1 composition.
  4. Shake it slowly for 15–20 times until uniformly mixed.
  5. Apply mixed material into cracks / caviies until full. wait till it dries.


Apply SikaCoat®-500 Super

  1. Mix SikaCoat®-500 Super manually or use a low speed mixer until it is completely homogeneous prior to application.
  2. Apply a generous base coat of SikaCoat®-500 Super using roller or brush.
  3. when touch dry, apply another layer of SikaCoat®-500 Super at different direction.
What is the consumption of cementitious waterproofing for swimming pools? What is the minimum number of layers required?

Sika recommends consumption of 1.0 kg per m² per coat and a minimum of 3.0 kg/m² is required for swimming pool.

What waterproofing products shall I use for swimming pools under tiles (both floor and wall)?

Sikalastic®-1 KMY, a one component fiber reinforced, flexible cementitious waterproofing is the recommended product for swimming pool waterproofing before tiles for both wall and floor.

How do I waterproof gypsum wallboard?

Due to the porosity of the gypsum surface, Sika recommends a primer coat before the application of cementitious waterproofing. Sika® Primer-11 WMY is required prior to the application of SikaTop® Seal-107 (MY), SikaTop® Seal-109 MY and Sikalastic®-1 KMY.  

Shall I lay the levelling screed below or on top of the cementitious waterproofing?

Common practice in Malaysia is:

  • The finishing is tile, the screed is normally applied before the waterproofing.
  • Bare concrete (without tile), the screed is normally applied after the waterproofing.
What is an angle-fillet? What is Sika® SealTape F (edge sealing tape)? And how do I decide on which one to use?

An angle fillet is incorporated at the base angle to round off the 90° right angle at the wall to floor joint to form a 45° angle. A typical angle fillet is formed using cementitious based material. Thus, it is hard and non-deformable. An edge tape is a thermoplastic elastomer (TPE) that is elastic in nature. The edge tape is an elastic system component that is used in combination with Sika waterproofing mortar to form a high elastic and crack bridging sealing tape around the edge and corners. Cement sand with latex (or SikaGrout®) angle-fillet is sufficient when a concrete kicker is provided. An edge tape is recommended for drywall or precast systems and also when a concrete kicker is not provided.

What is the consumption of cementitious waterproofing for bathrooms, toilets, and kitchens? What is the minimum number of layers required?

Sika recommends a consumption rate of 1.0 kg per m² per coat and a minimum of two coats are required for bathroom, toilets, and kitchen.

What is the bond strength of cementitious waterproofing?

Typical bond strength of cementitious waterproofing mortar ranges from 0.5–1.0 N/mm², depending on the type and grade of the products.  

What is the difference between site mix and pre-bagged screed?

Site mixing is done at the site by mixing cement, sand, and water with the estimated quantity of each material. It is often not properly mixed and very inconsistent in terms of quality control.

A pre-bagged screed is produced and packed in the factory with the predetermined ratio to ensure the mixing is homogeneous and the quality is controlled.

Can I apply tile adhesive directly onto the cementitious waterproofing?

Yes, most cementitious based tile adhesives should be able to apply directly onto the cementitious waterproofing mortar. However, please contact the manufacturer(s) to ensure the compatibility between the two products.

What waterproofing products shall I use for toilets, bathrooms, and kitchens?

In general, any cementitious based mortar and liquid applied bituminous coating are suitable be used for these areas.

What is the difference between rigid and flexible waterproofing?

Rigid cementitious waterproofing mortar is typically hard and non-deformable, whereas flexible cementitious waterproofing mortar is soft and deformable.

What is cementitious waterproofing mortar?

Cementitious waterproofing mortar is a ready-mixed waterproofing compound used to protect structures against water infiltration. They are supplied as ready-to-use solutions either in one single component or two-component packs to seal against damp soil, seepage and percolating water. In addition, cementitious waterproofing mortar can also be used for the protection of concrete structures. Waterproofing mortars are often applied in water reservoirs, water retaining structures, basements, and other engineering structures as well as beneath tiling for swimming pools, balconies, bathrooms, and kitchens.

Can I mix skim coats with latex?

It is not advisable to mix skim coats with latex. Only add the amount of clean water recommended.

Can I apply skim coat on external walls?

Yes. There are skim coats specially formulated for external walls.

For assistance, please contact us.

How long must I wait before painting over skim coats?

Generally, painting works can be carried-out after the skim coat has dried, around 7–14 days, subject to site condition.

How long does it take for skim coats to dry?

On drywall, skim coat normally takes about 2–3 days to dry.
On concrete surfaces or plastered walls, skim coat takes about 5–7 days to dry.
In extreme situations such as high humidity and constantly damp substrates, skim coats may take more than 7 days to dry.

How long must I wait before skimming over new concrete or new plastered wall?

It is advisable to wait at least 14–21 days before skimming work can commence on new concrete or new plastered wall. This will allow sufficient time for the new concrete or new plastered wall to fully cure.

Can I plaster and/or skim over old surfaces?

Yes. The old surfaces must be structurally sound, level, solid and stable, and free from dusts, dirt, oil, grease, standing water, laitance, paints, curing compound and any material / coatings that reduces bond. If the substrate contains any of these contaminants they must be removed by grinding, water-jetting, or sanding.

All dusts, loose and friable material must be removed, preferably by brush and/or vacuum before plastering / skimming.

Can I skim on drywall (gypsum, cement, plaster boards)?

Yes. Use only acrylic skim coats.

Sika’s Product:

What are the differences between skim coats and plasters?

Skim coats are fine mortars, and they are applied to a thickness < 5 mm. The surface of the skimmed area is smooth.

Plasters, on the other hand, are coarse mortars and they are applied to a thickness from 5–30 mm. The plaster surface is constantly rough.