Engineered Wood Flooring Float or Glue?

[revelation]

We are getting closer to fitting our flooring, we have Caberdek board on the first floor and the loft.  We are looking to put down engineered wood flooring on-top.  We have wet underfloor heating below and we're looking to float the flooring rather than glue it.  Firstly is that a bad idea?   If we go ahead with this method I was looking at using an underlay to help with sound deadening etc...   Would an underlay of say 2mm interfere with the heat from the underfloor heating?   Are theyre any underlays that anyone had had good experiences with?

 

 

[TonyT]

I would contact the technical people at the supplier of the floor and ask their opinion on their product, safer option.

 

 

[Adsibob]

On 17/02/2021 at 03:48, revelation said:

We are getting closer to fitting our flooring, we have Caberdek board on the first floor and the loft.  We are looking to put down engineered wood flooring on-top.  We have wet underfloor heating below and we're looking to float the flooring rather than glue it.  Firstly is that a bad idea?   If we go ahead with this method I was looking at using an underlay to help with sound deadening etc...   Would an underlay of say 2mm interfere with the heat from the underfloor heating?   Are theyre any underlays that anyone had had good experiences with?

 

 

I was advised by Cellecta, the company supplying our extruded polysterene UFH boards that anything you put down between that and the finished floor would slow down the heat transfer time. Engineered wood is already going to slow down the responsiveness so if you are going down that route then definitely avoid slowing it down further. Just put a 6mm layer of rubber matting, such as the one shown here, underneath the UFH boards. That will still absorb sound from impact of footsteps, without compromising your heating. If you don't have space for 6mm of rubber, they also do a thinner cork version, but I've not tried that.

[NCXo82ike]

resurrecting this thread. We have caberdeck 1st and 2nd floors. We'll be having ProWarm LoFlo UFH boards on top. Wood veneer SPC flooring to go on top (floating click design) which have the thinnest of foam underlays integrated. Running through a heat pump so maximum heat transfer at low flow temperatures is a priority. I'm concerned this buildup would be bad for impact noise below however. 

Since we haven't laid the UFH yet- I was thinking of putting rubber/cork underlay beneath the UFH boards so it wouldn't compromise the heat transfer above. 
The LoFlo manual suggests washers and screws every 300mm if above a timber floor- which I presume means there won't be significant bite from the screws on the UFH boards?
So that makes me think there would be a meaningful benefit to the underlay?
The UFH boards are rigid XPS foam as I understand so don't absorb impact noise.

 

Interested to know others' thoughts.

[JohnMo]

I did a similar build in our summer house, the floor performance for a given temperature (same flow temp as the house was pretty rubbish.

 

I would screed or self levelling compound over to get good contact with the pipes then glue a floor down, any air gaps act as insulation.

[saveasteading]

we had a screed with ufh, over chipboard. As a last minute decision we decided to lay 5mm rubber matting first (between floorboards and the eggbox grid).  the logic was simply that there was one chance to do it.

as it happens it proved useful as the plastic grid did not fit well/ was not fitted well and had areas not touching the floor. Having the matting meant that normal staples bit into the mat and held the grid down.

perhaps the staples would have gripped the boards equally well.

 

we will never know if it makes a big difference. My hunch is that it will make  a difference for low frequencies and running footsteps.

we ordered online and it came in 2 days. very good quality , clearly made of car tyres and well bonded yet squidgy enough. it reminded me of the matting on a golf range tee-off area.... and surplus will become that and a football goal areas on our field.

 

so yes, we decided to do it. The moral though is to diy the matting or watch the installation. Ours was very ropey with overlaps and gaps with speed dominating over quality.. followed of course by umpteen excuses.