screed on underfloor heating system

huangyhg

screed on underfloor heating system
70mm (2.5") of make up floor screed (sand, cement, 3mm aggregate) is proposed over eswa underfloor heating cables (40degreec). is anti crack mesh necessary in this screed?
should this mesh include allowance for additional temperature steel as the screed will experience hot and cold temperatures over its life span?
i have had exactly the same problem in an underfloor heated area in a new school.  
the presence of the grid of underfloor heating pipes makes the placing of the mesh difficult.  also, the pipes used in the school project were of hdpe, and were easily damaged and holed.
after discussions with the underfloor heating sub-contractor, i used a fibermesh grp reinforcement, which was added to the screed in the batching plant.
a recent inspection has shown that this is performing well.