Sikafloor®-421 Therm Screed
Sikafloor®-421 Therm Screed is a lightweight insulating screed suitable for floors of houses, buildings, or other structures. It is applied in the same way as floor screed and is processed by hand and/or machine.
- Pre-packed lightweight insulated screed, ready-to-use
- Chemically stabilized to avoid EPS beads from floating upwards
- Density of approx. 250 kg/m³
- Low thermal conductivity
- Allows reduction in structural dead load
- Acoustic insulation
- Water repellent to avoid loss of insulation properties after rain
- Non-flammable
Usage
- Insulation lightweight screed on roofs
- Lightweight protective screed
- Lightweight floor underlayment, under carpets and tiles
Advantages
- Pre-packed lightweight insulated screed, ready-to-use
- Chemically stabilized to avoid EPS beads from floating upwards
- Density of approx. 250 kg/m³
- Low thermal conductivity
- Allows reduction in structural dead load
- Acoustic insulation
- Water repellent to avoid loss of insulation properties after rain
- Non-flammable
Packaging
17 Kg bag
Product Details
Chemical Base
1 bags of 17 kg Sikafloor®-421 Therm Screed
100 litres of Crushed EPS Beads (0 - 4 mm)
(EPS beads density 1.2 kg/ 100 Liter)
Shelf Life
12 months from manufacture date
Storage Conditions
Store properly in original, unopened and undamaged sealed packaging in dry conditions at temperatures between +5 °C and +30 °C. Protect from direct sunlight.
Density
| Approx. 200 - 250 kg/m³ | (Dry) |
Application
Mixing Ratio
| Material | Weight |
| Sikafloor®-421 Therm Screed | 1 x 17 kg |
| Crushed EPS Beads (0 - 4 mm) | 100 Litres (EPS beads density 1.2 kg / 100 Liters) |
| Water | 18.5 - 20.5 Litres |
Ambient Air Temperature
+6 ºC min/ +40 ºC max.
Substrate Temperature
+6 ºC min/ +40 ºC max.
Pot Life
60 - 120 min
Yield
Approx. 100 Litres
SUBSTRATE QUALITY
The substrate must be clean, sound, dust free without any traces of oil, laitance, curing compound and other contaminants. The substrate must be fully cured and is sound enough to receive the weight of Sikafloor®-421 Therm Screed.
Deeply contaminated substrate must be abraded to clean and sound surface.
MIXING
- Drum mixer with a minimum capacity of 150 Ltr is required for mixing.
- Pour the require amount of clean water into the mixing drum.
- Pour in the required Sikafloor®-421 Therm Screed into the drum while mixing.
- Mix for 2 - 3 minutes, until a homogenous slurry is obtained.
- Lastly, add in the required crushed EPS Beads and continue mixing for 5 - 15 minutes until clumps are eliminated and a smooth consistency of mortar is achieved.
APPLICATION
Primer
Prime with a slurry scratch coat/key coat by mixing Davco 751 with cement and fine sand at 1:1:1 ratio. Apply a thin coat to form key coat and leave it to dry.
Pour the light-weight insulation screed onto the primed substrate. Then use a straightedge to level-off the screed to the required thickness and levels. (Max. Thickness 100mm)
Additional layers: Allow the previous layer of lightweight screed to cure for up to 7 days or until it cures.
Apply another layer of primer and leave it to dry before adding the additional layer of lightweight screed.
Sealing layer (Optional): After the insulation screed has hardened, use a steel trowel to smoothen the surface with a sealing layer (Davco Polycrete @ 3 - 5 mm thick, coverage 7.0-11.5kg/m²).
Concealed roof: Apply Sika waterproofing solution (liquid or sheet membrane) according to the related Sika Method Statement.
- Pour the lightweight insulation screed directly on top of the waterproofing layer. Then use a straightedge to level-off the screed to the required thickness and levels. (Sarnafil PVC membranes must be protected with a layer of geotextile).
- Sealing layer. After the insulation screed has hardened, use a steel trowel to smoothen the surface with a sealing layer. After the sealing layer has hardened, it is recommended that induce/control joints are saw-cut at the required intervals base on engineer’s requirement. Seal the joints with Sika approved sealants.
Lightweight floor underlayment
Leave the final layer of lightweight screed to cure for 24 hours.
Apply a slurry key coat using Davco 751 onto the lightweight screed. Then apply al ayer of 20 mm Davco Floor Screed before application of tiling, carpet or parquet work. A Use Sika approved tile adhesive or levelling compound.
CURING TREATMENT
Protect the lightweight screed from early hydration using a curing compound or wet hessian
CLEANING
- Clean mixing and application equipment with water immediately following use.
- Remove splatter or spills with water before material sets.