Koster SL Protect - High Wear Resistant Cement-based Underlayment

Manufacturer guidance

• Substrate has to be sound and solid as well as free of bond inhibiting agents such as grease and oil.
• Remove all bond breaking substances such as laitance, loose particles, dust, formwork release oil, etc.
• The substrate can be prepared according to need by shotblasting, grinding, or sweeping and vacuuming.
• Do not acid etch substrates or clean the substrate with chemicals.
• Joints in the substrate have to be re-created in each successive layer; do not bridge expansion joints with KÖSTER SL Protect.
• Concrete and screed substrates are primed with KÖSTER SL Primer to reduce absorption before application.
• Non absorbent substrates are primed with KÖSTER VAP I 06 Primer.
• Do not apply over adhesive residue.
• The minimum tensile strength of the substrate for wheel trafficked areas is 1.5 N/mm².

Manufacturer guidance

General:

• Mix each 25 kg bag of KÖSTER SL Protect with 3.0 liters of potable water.
• The water is placed in a clean mixing vessel and the powder added while constantly mixing.
• Use a double paddle mixer and mix intensively for no less than 3 minutes until a flowable, lump free consistency is reached.
• We recommend to always mix 2 bags with a total of 6.0 l of water at once.
• When feathering out the material in very thin layers a maximum of 0.5 liters of water may be added per bag.
• Distribute the material in the desired layer thickness directly after mixing.
• Mix and distribute the material in a constant work flow to avoid visible work edges.
• The material is self-levelling when working “fresh in fresh”.
• While working larger areas use a KÖSTER Gauging Rake to distribute the material.
• Rolling the surface with a KÖSTER Spiked Roller immediately after distribution creates a very smooth surface through better de-airing.
• Install the KÖSTER SL Protect within 20 minutes.
• Do not delay successive pours by more than 10 minutes to avoid visible work edges.
• The surface quality of the underlayment depends on workmanship, layer thickness, and curing parameters so that variations from a sample surface may occur.
• Moisture sensitive floor coverings and sealers may not be applied before the material has fully cured.
• Install KÖSTER SL Protect in one layer and not in multiple lifts.
• Depending on the temperature it may take between 24 and 72 hours for the material to attain a residual moisture content of less than 3 M%.
• Only apply at temperatures between + 5 °C and + 30 °C.
• Low temperatures will increase the pot life and high temperatures will decrease the pot life.
• Protect KÖSTER SL products from premature drying through sun and drafting air currents.
• When installing in wet areas apply a protective coating or system.
• The surface appearance of the underlayment is dependent on the workmanship, layer thickness, and curing parameters.
• There may be differences in appearance to test areas.
• Do not install moisture sensitive floorings and coatings before the underlayment has completely cured to a residual moisture content of less than 3 M %, depending on layer thickness and environmental condtitions between 24 and 72 hours.
• Sand the surface thoroughly before applying reactive resins.

Required tools:

• Drill with basket mixer, BEBA mixer, compulsory mixer, mortar pump with compulsory mixer, transport and pouring tools, buckets, gauging rake, spiked roller.

After treatment:

• Curing can be aided by covering the hardened material with polyethylene sheets.
• This reduces surface shrinkage tension especially when the material has been applied in thick layers.

Manufacturer guidance

• Application temperature: + 5 °C - + 30 °C.
• Pot life: approx. 30 min.
• Mixed density: 1.9 g/cm³.
• Compressive strength (7 days): > 25 N/mm².
• Compressive strength (28 days): > 45 N/mm².
• Bending tensile strength (7 days): > 5 N/mm².
• Bending tensile strength (28 days): > 10 N/mm².
• Resistant to foot traffic after approx. 3 hours*.
• Modulus of elasticity: > 15000 N/mm².
• Shrinkage: < 0.5 mm/m.
• Layer thickness 5 - 30 mm, (can be feathered out to 3 mm).

*depending on temperature.