What is a plasterer’s float?

A plasterer’s float is a flat blade with a handle, used to bring freshly applied plaster or render to an even, plumb surface. The trowel puts the material on the wall and the straightedge rules off the excess; the float is what levels the surface and closes it up.

Form and materials

The blade is rectangular with the handle mounted centrally on the back, so the hand stays clear of the wet mix. A steel version has a blade roughly 30 cm long and 10 cm wide, with a bracket welded square to the blade carrying the handle. The length lets you cover a good width of wall in a single pass.

Type	Character	Typical use
Wood float	Light, leaves an open, grainy texture	Traditional floating of render and base coats
Plastic float	Light, easy to clean	General levelling and rubbing up
Steel float	Stiff, holds a straight edge	Compacting and flattening a base coat
Sponge or felt float	Soft, mildly abrasive	Wet rubbing up and finishing texture

Working sequence

1. Lay on the material with the trowel, slightly proud of the finished thickness.
2. Rule off with a straightedge between the screeds or beads, taking away the surplus.
3. Float the surface with the plasterer’s float held flat against the wall, using light circular movements so that hollows fill and high spots are cut back.
4. Check for plumb and flatness with a straightedge or long level while the mix is still workable.
5. Rub up or scour later, once the material has firmed, to close the surface or leave the texture the next coat needs.

Timing decides the result. Float too early and the surface drags and ripples; float too late and the material has set beyond correction.

Float versus finishing trowel

The float does the coarser work. A finishing trowel has a thin, flexible steel blade and is used to polish the final skim coat, not to flatten a base coat.

Related terms

• Scratch coat
• Render
• Finishing trowel
• Straightedge
• Screed bead
• Skim coat

Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.