carpet ready hollow core planks

huangyhg

carpet ready hollow core planks
does anyone have any experience with using carpet ready hollow core plank?
we have an architect who is pushing to use it to reduce any topping and maximize floor to floor heights. has anyone seen this in the field?  any constructability issues that your aware of or is the product as good as it claims?
i appreciate all your input.  
talk to the mfg???  he would know best!!
yes, i have used carpet directly over precast plank (no topping). i am not sure all precast suppliers will do this (so it might lock you in to only one h.c manufacturer).
their construction technique is interesting to say the least. before they grout the joints they insert a small jack to bring adjacent plank top surfaces together as level as they can, then they grout the joint between planks. then they latex the surface and grind it smooth. check with the local precasters who will do it and who will not. also, check cost differences between this and a concrete topping....if i re  
all i'm getting from the manufacturer is that "its a great product.  no camber or deflection issues.  set the planks and your floor is ready"  

i'm looking for a non-salesmen's opinion. any engineers have experience with this product?
   
thanks jike - great input. one question - what do you mean by:
"before they grout the joints they insert a small jack to bring adjacent plank top surfaces together as level as they can, then they grout the joint between planks."
what exactly are they jacking? can you explain this process to me in more detail?

i never had any performance problems with carpet direct and it was good quality job. just make sure the plank can still function as a diaphragm for your loads.
when planks are set in place in the field, there is often some small elevation difference between the top surfaces of the plank since each one has a little different camber. for a carpet direct job, the erector will pull the low plank up to the same elevation as the higher plank and then lock them together by grouting the joint. this minimizes the amount of latexing and grinding that is required.
as the spans and loads get large so does the camber. if the framing layout is not uniform (such that the planks span opposite directions or the bearing locations differ between adjacent planks) it makes matching the tops difficult or impossible.
we've have plenty of difficulty getting a level floor where we had topping to work with. with no topping it must be an order of magnitude more difficult.
we just did a job where the manufactured camber was "calculated" to be 1.25" and the in place camber actually varied from < 1" to 1.75". i am curious as to what method the precaster uses in a "carpet ready" system that he doesn't use in a traditional system which will receive a topping.   
topping is a great addition to hollowcore planks with an increase of net strength and a chance for wwf in the topping.  allows for differential camber and attenuates noise transmission.  leaving it out still requires the grout keys for unitized action between adjacent planks and makes framing around holes in the system problematic.
as you initially select plank thicknesses, you need to be conservative so as not to have to deal with large cambers later on. be sure to take into account fire rating and clear cover of the strands. camber is only a guess and can change over time as you have observed.
for unusual situations, i would advise to avoid using the carpet direct application.