Engineered wood flooring underlay

[Tallboyrip]

Here's what the Technical Service Consultant said:

'Before installing, it is imperative that the Relative humidity of the subfloor is below 75% Rh, if you decide to install the floor as a floating floor, we advise that you lay a suitable surface dpm.

As you have indicated that the floor will incorporate an underfloor heating pipe system, this should be commissioned at an early stage to ensure that residual construction moisture is forced out and that the floor is dry to below 75%Rh.'

 

[mointainwalker]

http://www.bostik.co.uk/construction/product/laybond/L73-Multicryl/202/technicalData

If you check the above from Laybond - part of Bostik - you will see that it must also be below 75% RH to use glue, so no exclusion from that point of view.

That apart, your quote says

if you decide to install the floor as a floating floor, we advise that you lay a suitable surface dpm.

. It does not say anything about you must use a dpm or that you must not glue.

Anyway, your choice.

 

[WoodYouLike]

Be careful with these 75% RH indications - for anhydrite the reading must be lower!
(Or in MC%: normal screed below 2%, anhydrite below 0.3%

 

[mointainwalker]

WYL

This link lists the materials it is suitable for and they include sodium sulphate ( anhydride ) screeds.

What do you think is correct and can you give any links ?

 

[WoodYouLike]

To be honest, we never use RH to check the moist content of a concrete/screed floor. The moist measure equipment we have gives us the MC (as most, if not all, European equipment does - only in the UK do they stick to using RH strangely enough).

If you do need to check if that 75% RH also applies to anhydrite screed you would be better off calling the technical department of the product you're using.