Solid bamboo underlay on floorboards advice please

[JohnnyS]

Hi all,

after a bit of advice please, I have some solid bamboo flooring being fitted tomorrow.
At the moment I have some 'combilay' damp proof underlay and fibreboard underlay (5mm)...... the combilay was going to go down first then the fibreboard, the underfloor is floorboards (downstairs sitting room).

If I used the combilay will this cause the floors boards to sweat, should I just used the fibreboards instead? The fibreboard instruction sheet (from memory) asks that the underfloor serves as a dpm but the advice seems to be a dpm should not be used on floorboards....help please!

Cheers
John

 

[JohnnyS]

If it makes any difference the combilay stuff says that it can be used on any any floor but i'm not to sure if I should trust it on my floorboards.

Cheers
John

 

[WoodYouLike]

If it makes any difference the combilay stuff says that it can be used on any any floor but i'm not to sure if I should trust it on my floorboards.

Cheers
John

Sorry John, but Combi-underlayment (containing a DPM) CANNOT be used on any floor. Never use this type of underlayment over existing floorboards or sheetmaterial (like chipboard, plywood). It will cause condensation, sweating and could even rot the joists.
So you are right about not trusting it.

Leave it out.

 

[JohnnyS]

Thank you very much! I decided not to use it lastnight but thankfully you have confirmed its not good for what i'm doing, appreciate the help!

Cheers
John