Flow Testing Kits for Liquid Screed: How achieving the correct flow is vital for a perfect pour!

What Is A Flow Test? 

Flow testing of liquid screed is carried out to determine the flowability / slump of the screed. To do this, a stainless-steel flow cone (AKA slump cone) is placed on the clean dry stainless-steel flow plate (AKA slump plate).  

The cone is then filled with screed. Once full, the cone is removed, and the spread / slump is measured to determine the flowability of the liquid screed before application.  

There are various types of screed applications; bonded screeds, unbonded screeds, floating screeds and underfloor heating screeds. 

• A bonded screed is simply a screed that is bonded to a substrate. This would usually be to a concrete slab or a beam and block floor. 
• An unbonded screed is, exactly as its name suggests, one that is not bonded to its substrate.  
• Floating screed simply means that the screed is overlaid on something that is compressible and not rigid. 

• Underfloor heating screed is essentially screed laid over your underfloor heating system. 

Why Should A Flow Test Be Carried Out on Site? 

Flow tests should always be carried out at the production plant first and then most importantly on site using a flow kit before starting the pour. This is very important as it ensures that the screed has the correct consistency and is workable. The main benefit of this is no drying shrinkage or any related problems. 

A non-workable screed can occur when: 

• The mixture is too wet – this allows coarse aggregates to settle at the bottom and results in the screed becoming non-uniform in its composition. 
• The mixture is too dry – this will result in the screed being difficult to handle and place correctly in position. 

Testing for flowability ensures that quality is never compromised and guarantees a high performance, free flowing, self-compacting liquid screed. 

Metex Flow Cones & Flow Plates are available separately or as part of a ‘Liquid Screed Flow Test Kit’. For more information, our Screed & Concrete Tools Knowledge Base is here to help! To purchase Metex screed levelling tools, click here or see below.