Subfloor levelling explained: what it is, when you need it, and why it matters

Subfloor levelling explained

Most flooring problems start underneath the floor.

When levelling is usually needed

• Uneven concrete (high spots/low spots)
• Old adhesive residue
• Damaged floorboards or loose boards
• LVT/SPC installations (they show imperfections quickly)

What fitters use

• Smoothing compound / latex leveller
• Plywood overlays (some timber subfloors)
• DPM / moisture barriers (when required)

What to agree in advance

• Who supplies materials
• Drying times (and what happens if it needs longer)
• Whether skirting/doors need trimming after levelling

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A fitter who talks confidently about the subfloor is usually the one you want.