How to Apply Screed for a Smooth Floor
How to get a smooth solid floor
Self-smoothing screeds or ‘underlayments’, such as Ardit Z8 and Plycolay, are an easy method of preparing uneven concrete or quarry-tiled floors before laying tiles, sheet vinyl, wood blocks or parquet panels. The material is poured on to the floor and levelled roughly with a steel trowel, after which it spreads out by itself to form a smooth surface.
It is intended to correct only minor irregularities and is unsuitable for floors affected significantly by rising damp — such as brick floors laid directly on earth — or for covering suspended timber floors or wood block floors. If there is the slightest risk of damp, use vinyl asbestos tiles (which `breathe’) rather than vinyl; do not lay wood block floors.
Before applying the screed, wash the floor with detergent to remove grease and polish; sweep away loose dirt. When applied to absorbent surfaces, such as concrete, the screed can be walked on in an hour or so and the floor covering laid next day. Drying takes up to 24 hours on non-absorbent undersurfaces, such as quarry tiles.
Prime non-absorbent surfaces, such as quarry tiles, with anprimer (eg. Ardex Neoprene or Isobond). Dampen absorbent surfaces with water.
Mix the powder with water. Stir the mixture into a creamy paste, then pour part of it on to the floor at the furthest point from the door.
Spread the material evenly over the floor, using a steel trowel, to an average thickness of 3 mm (1/8 in). The self-smoothing action removes trowel marks.