DPM and timber floors

[johnnyg]

Is there a need to lay a sheet of DPM under your underlay when laying laminate floors on a precast concrete first floor, we have UFH so there would never be damp as such or am i missing something?

 

[AMatt]

I laid a laminate floor last year in my dining room and was also confused about laying a DPM. A local handyman (not an expert!) said there was no need as there was already DPM under the concrete floor. He said that if we put another layer down there was a good chance of 'sweating' - condensation I presume he meant. I took his advice and everything is fine, so far...