Building Construction Handbook, Eighth Edition

Concrete Floor Screeds ~ these are used to give a concrete floor

a finish suitable to receive the floor finish or covering specified. It

should be noted that it is not always necessary or desirable to

apply a floor screed to receive a floor covering, techniques are

available to enable the concrete floor surface to be prepared at

the time of casting to receive the coverings at a later stage.

Typical Screed Mixes ~

Laying Floor Screeds ~ floor screeds should not be laid in bays

since this can cause curling at the edges, screeds can however be

laid in 3„000 wide strips to receive thin coverings. Levelling of

screeds is achieved by working to levelled timber screeding batten

or alternatively a 75 mm wide band of levelled screed with square

edges can be laid to the perimeter of the floor prior to the general

screed laying operation.

Monolithic Screeds †

screed laid directly on concrete

floor slab within three hours of

placing concrete † before any

screed is placed all surface

water should be removed † all

screeding work should be

carried out from scaffold board

runways to avoid walking on

the `green' concrete slab.

Screed

Thickness

Cement Dry Fine

Aggregate

<5 mm

Coarse Aggregate

>5 mm <10 mm

up to 40 mm | 3 to 4 1/2 †

40 to 75 mm

| 3 to 4 1/2 †

| 1 1/2 3

Concrete Floor Screeds