Unbonded screeds

• Where a screed is laid on an impermeable dpm , there will be no bond between the screed and the concrete base so that drying shrngkage of the screed is unrestrained
• The screed should be at least 500mm thick so that it does not dry too rapidly and suffer shringkage cracking

(screed laid onto impermeable DPM unbonded to concrete slab )

Floating screeds

• A screeds laid on a layer of compressible thermal or sound insulating material should be at leat 65mm thick and teinforced with light mesh,
• THis will prevent the screed cracks due to drying shringkage and deflection under loads on the floor