Self-levelling concrete is useful for correcting minor surface irregularities, but it isn’t suitable for every situation. Using it in the wrong conditions can lead to cracks, weak surfaces and flooring failures, particularly on refurbishment projects where the existing subfloor may be unpredictable.
When major floor build-up is required
Self-levelling products are designed for thin layers. If a floor requires significant height adjustment or major levelling, they should not be used as a substitute for screed. Attempting to build up thick layers can result in poor strength and cracking. In these cases, traditional screed or liquid screed is usually the correct solution.
When the subfloor is unstable
Self-levelling materials rely on a stable and well-prepared base. They should not be applied over:
- cracked or moving concrete
- surfaces contaminated with oil, grease or adhesive residues
- old paint or coatings that are poorly bonded
- loose or dusty substrates
If the base surface is not sound, the levelling layer is likely to fail.
When moisture levels are high
High moisture levels can interfere with curing and lead to problems such as debonding, blistering or soft surfaces. Basements and older ground floors without proper damp-proof protection should be assessed carefully before levelling products are applied.
When floors will experience heavy loads
Self-levelling compounds are not designed to act as structural flooring. In areas such as garages, workshops or commercial spaces with heavy point loads, a properly specified screed system is usually required.
When preparation is rushed
Although some levelling products dry quickly, skipping preparation steps such as priming and substrate checks can lead to failure.
Why choose LMA Floor Screeding London?
With over 15 years of experience, LMA Floor Screeding London provides expert advice and reliable screed installations across London.