How to use Sikafloor 125 Level Flex

Achieving a flat, professional-quality floor starts long before your final covering goes down. Sikafloor 125 Level Flex is a flexible, self-levelling compound designed to help you correct uneven surfaces quickly and reliably, whether you’re prepping for vinyl, tiles or engineered wood.

This guide walks you through the process step by step, from preparation through to curing, so you can get the best possible result first time.

Sikafloor 125 Level Flex is a polymer-modified, self-levelling compound formulated for internal floors. Its flexibility helps it cope with slight movement in the substrate, while its free-flowing consistency makes it easy to achieve a smooth, even finish with minimal effort.

It’s suitable for use over sound concrete and cement-based screeds and is commonly used ahead of resilient floor coverings.

Preparation is the most important stage of the job. Even the best levelling compound won’t perform well on a poorly prepared surface.

• Make sure the floor is clean, solid and dry
• Remove all dust, loose material, paint residue, grease or adhesive
• Repair cracks or weak areas before levelling
• Ensure concrete or screeds are fully cured and protected by a damp-proof membrane

Priming the substrate 

Priming improves adhesion and prevents rapid moisture loss.

• Porous surfaces should be primed and left to dry before application
• Highly absorbent floors may need a second coat
• Smooth or non-porous surfaces, such as tiles, should be mechanically keyed or treated with a suitable bonding primer

Taking time at this stage helps prevent cracking, pinholes and debonding later.

• Accurate mixing is key to achieving good flow and strength.
• Add 3.4-3.5 litres of clean water to a clean bucket
• Gradually add the powder to the water
• Mix using a slow-speed paddle mixer until the compound is smooth and lump-free
• Mix for around 3 minutes, scraping the sides if needed

Do not add extra water once mixed, this weakens the compound and affects performance. Once mixed, the material should be used promptly while workable.

Once mixed, the compound is ready to pour.

• Pour directly onto the prepared floor
• Allow the material to flow naturally, guiding it with a steel trowel
• Spread evenly and work it into low spots
• The product can be applied up to 6 mm thick per layer

To achieve the best finish:

• Use a spiked roller shortly after pouring to release trapped air
• Feather edges carefully to blend into surrounding areas
• Work methodically and avoid overworking the surface

If additional thickness is required, allow the first layer to dry, reprime and apply a second coat.

Clean tools and mixing equipment with water immediately after use. Once the compound sets, removal becomes difficult and often requires mechanical cleaning.

• Skipping priming or applying to dusty surfaces
• Adding extra water to improve flow
• Applying over damp or unstable substrates
• Rushing the curing process

Attention to detail at each stage makes a noticeable difference to the result.

Sikafloor 125 Level Flex is a reliable choice for producing smooth, level floors when used correctly. With careful preparation, accurate mixing and controlled application, it provides an excellent base for a wide range of floor finishes.

If you’re unsure about compatibility or application conditions, Solseal’s team is always happy to offer advice before you start.