Dpc Under Hardiebacker

[Ben_A1990]

Hi all

Please could somebody let me know if a DPC is required with HardieBacker? Taking up the fake wood floors reveals a DPC. Would Hardiebacker under ceramic floor tiles be enough by itself? or do we need a roll of damp course?

Thanks

 

[Qwerty]

Any photos of the subfloor or DPC you referred to?

 

[Spare Tool]

Only a guess as no pic but most laminate wood floors generally have a thin foam membrain laid loose underneath, its more for cushioning than a dpm, if its just that remove it and stick and screw hardi straight onto wood substrate..

 

[Qwerty]

He may be referring to bitumen covering on the floor

 

[Spare Tool]

He may be referring to bitumen covering on the floor

Never thought of that, hardi wrong choice then if that's the case..

 

[Stef]

Only a guess as no pic but most laminate wood floors generally have a thin foam membrain laid loose underneath, its more for cushioning than a dpm, if its just that remove it and stick and screw hardi straight onto wood substrate..

On reading the post I would think that it's the foam under the laminate.

 

[Ben_A1990]

Thanks for all the prompt replies.

I will take up both flooring later and put up photos, got a few obligations this afternoon. Will be about 8pm, if anybody is online to have a look and reply tonight I would be extremely grateful.

Cheers

Ben

 

[Time's Ran Out]

Can't wait!

 

[Ben_A1990]

The green type says DPC (and other things) and is above an old layer of tiles. Seems really solid underneath. This is in the hall.

The grey one doesnt say anything and is in a garage coversion, doesnt sound as solid underneath.

Cheers

 

[Chalker]

The dpm can be thrown away. But the vinyl tiles will need a different approach

 

[Ben_A1990]

Im not an expert in DIY, but they dont seem like vinyl. They are hard.

 

[White Room]

They used to heat them when cutting then fix because they were rigid.

 

[Ben_A1990]

Just lifted some more of the green stuff out of the way. The edges of some of the tiles have cracked by the skirting board. I am 99% sure they are not vinyl. When I scratch the edge with a screwdriver they create dust and do not peel in any way.

Going back to the original question. Do I need any DPC under hardie backer with these surfaces?

 

[White Room]

The age they are you'd best check there not the ones that contain asbestos.

 

[Qwerty]

No, you don't need any DPM.

Both floors you have have got laminate foam underlay as @Andystiletiling said. This can just be thrown away. I was also right (in a roundabout way!) in that you have old Marley thermoplastic tiles which are stuck down with bitumen (black) adhesive. These are brittle and if they are breaking up near the perimeter then it is a pretty good sign most others will soon follow suit. They usually contain very low grade asbestos but check with your local waste disposal site to check that they accept these, most do in local landfill. Take care when removing for dust etc and most usually come up whole or near whole.

You don't need hardiebacker from what I have seen, but could benefit from slurry coating over the whole floor where bitumen adhesive is present and tiling that.