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Does self levelling compound crack?

A self-levelling compound will have a tendency to crack as it is only applied in a very thin layer. This is usually between 3mm-10mm just thick enough to smooth imperfections in the floor. Once the floor is level a floor covering can be easily applied, this could be LVT, tile, laminate etc.

Important: Note Self-levelling compound cannot be used as a finished floor covering unless you buy a special version.

flaking self level

flaking self-level

What causes self-levelling compound to crack?

There are two main reasons self-levelling compound will start to crack. One is poor bonding to the substrate material. The other is movement in the subfloor.

Both these problems can be solved using a 2 part latex-based self-levelling compound. The latex and self-levelling cement mix will adhere to almost any subfloor.

Because the self-levelling cement is mixed with latex rather than water, the self-levelling compound maintains a certain level of flexibility. Making it suitable for 1st floors or suspended timber ground floors – where you have timber joists covered with wooden floorboards or chipboard flooring sheets.

Cement-based self-levelling compounds that you only mix with water, are far more prone to cracking.

What is self levelling compound?

Self-levelling compound is also known as a floor screed or floor levelling mix. It is a thin layer of a cement-based mixture that is applied to subfloors in order to level out any bumps.

The mix is applied in a thin layer to subfloors such as concrete and floorboards, you use it before laying another floor, such as tile, above it.

It is called self levelling compound as it, in theory, self-levels. What this means is that you don’t have to worry about getting the mix perfectly level. It should flow across the floor, and correct any errors.

While this does generally work, there are limits. It doesn’t flow like water so will not perfectly level over a large area and may require a bit of help from you.

Why use self levelling compound?

You use a self levelling compound to turn a bumpy, un-even subfloor into a perfectly smooth surface. This is great when you are fitting a solid floor such as tile or wood.

Your floor wont be able to hide the bumps and just sit on them when you fit a rigid floor. Tiles will crack and break and a wood floor will bounce and move. Whereas a flooring like carpet will happily sit on an uneven base.

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