I have recently purchased an engineered wood floor and wish to install this over underfloor heating (A Nu-Heat water based solution which sits between the joists). The joists are currently covered with a thin layer of plywood and my plan is to install on top of this. I have been advised not to float the floor but cannot find a suitable underlay alternative to use.

I have spotted the Elastilon Lock product as a double sided adhesive underlay allowing me to fully bond the floor to the plywood layer - but its website description suggests it only allows for minimal tolerances (presumably in expansion/contraction) and is aimed at parquet style floors.

Would this be suitable for a standard plank engineered wood flooring, or could you suggest an alternative?

For reference the floor I have purchased is


And Elastilon Lock website:


  • What's wrong with doing a standard nail or staple install with no underlayment? You can drive the fasteners into the joists to avoid puncturing your hydronic tubing.
    – iLikeDirt
    Commented Mar 28, 2016 at 13:19

1 Answer 1


I don't know why you would've been advised to glue or lock a floating floor down. This a very bad idea & could make the floor cup or ridge if the floor can't move. Parquet is very different in being extremely small pieces with extremely small omnidirectional movement in a whole lot of very small areas.

Having no underlayment is the typical way & allows any moisture from condensation to escape, radiant floor's secondary activity. Foremost, is abiding by the Flooring Manufacturer's written instructions & approvals (over the phone means nothing) above & beyond whatever I or anyone else tells you. Do what the Warrantor says & even file pictures away to back up your by-the-book professional installation.

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