LVT Prep - Ply Over Hardboard?

[LVTnewbie]

Considering laying LVT in an upstairs home office to replace the existing carpet - I'm a relatively competent DIYer looking for a fun project, I’ve done copious amounts of research on LVT brands, adhesives, techniques and tools, and the one outstanding question I have is on prepping the subfloor.

The house is a modern 10 year-old build (Barratt, if it matters), and I haven’t lifted any carpet yet, but the existing subfloor is most likely hardboard. All of the advice I’ve been able to find online mentions plywood (specially flooring-grade) is the preferred subfloor, and that adhesive may have a hard time bonding to hardboard.

However, all of this is coming from the angle of installing hardboard over floorboards, not reusing an existing subfloor. So … should I install ply over the top of the existing hardboard, or would the hardboard itself be enough of a base for the LVT?

 

[simplesteve]

Your question might already be answered, when you lift the carpet and find that it is in fact already ply’d !

 

[LVTnewbie]

Your question might already be answered, when you lift the carpet and find that it is in fact already ply’d !

Good point - I’ve just lifted the carpet and confirmed … hardboard.

At this point I’m pretty sure I’ll need to ply over it and then apply skim coat to joins and nail/screw heads?

 

[simplesteve]

Hard to tell from that photo - but that looks like chipboard to me ?
Anyway, if you are ' plying ', all you need are Ringshank nails. No need for anything over the tops or joins.

 

[LVTnewbie]

Hard to tell from that photo - but that looks like chipboard to me ?
Anyway, if you are ' plying ', all you need are Ringshank nails. No need for anything over the tops or joins.

Interesting - everything I've seen mentions feathering/skim on top of joins etc. Wouldn't the nail or screw heads show through the finished flooring?

 

[crazydaze]

You'll need 6mm Flooring Grade SP101 Ply , fix with ring shanks and then feather all the joints and heads.

Then glue the LVT on-top.

If you are laying the LVT Herringbone, we would Mapei Renovation 3mm Coat Screed over the ply instead of feather.

 

[foxhole]

Definitely chipboard , all my LVT has been laid over chipboard .