Underlay req? - engineered wooden floor & 6mm plywood

[LordScull]

Hi

Firstly, great site, dip in a lot but my first post.

I intend to tongue tite 18mm engineered wooden floor onto 6mm plywood screwed to existing 18mm floorboards. 6mm ply is used to even out the existing floorboards.

Question 1: do i need underlay i.e existing wooden floorboards -> 6mm plywood -> underlay -> engineered wooden flooring

Q2: there is a concrete hearth which will be covered. Can I just cover it with the ply or should I put underlay just over that?

I have seen this topic discovered at length but not exactly as above.

Thank you

LS

 

[pinenot]

From my perspective I would use an underlay between the ex floorboards and ply to help even out undulations...pinenot

 

[LordScull]

Thanks for the advice...originally I was going to do without the underlay but on closer inspection there is some levelling required; particularly around the concrete hearth.

Any particular underlay that stands out or more importantly, any to avoid?

LS

 

[pinenot]

No ones that I know to avoid, just make sure it's fit for purpose...pinenot

 

[LordScull]

Will have a look online for something suitable

Thanks again