How to add a vapour barrier between concrete and hardwood flooring?

[JeffTrish]

I have Blackbutt hardwood flooring throughout my house. In some places along the outside walls the flooring has lifted. The house is built on grade. I have started removing the bad areas and have found that there is moisture wicking up through the concrete, about 4 boards out from the wall. There was never a vapour barrier put down on the concrete under the flooring. Should there have been? The flooring was glued?! down with what looks like some sort of mastic. My questions are: what do I use for a vapour barrier over the concrete, and what do you use to stick the boards down; a glue or a mastic or what. I can supply photos if required. 

[JacobZ]

Hi @JeffTrish,

Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you with us.

Any photos you can provide will be a great help. Let me know if you need a hand uploading images, I'd be happy to help.

If it is a timber product such as tongue and groove flooring or engineered timber flooring, there should certainly be a vapour barrier between it and the concrete.

Unfortunately, the only product I have found that would be suitable for this application is this Selleys Liquid Nails VBS Vapour Barrier which would need to be ordered through our Special Orders team. 

The advice I have received from Selleys is that this product is intended to be used over the entirety of the concreted area as painting it on one small area would prevent it from getting through there, but the water might migrate elsewhere in the floor and find its way through.  If you were able to remove the full extent of the hardwood floor and painted this product over the entire floor, it would be much more effective.

Once the vapour barrier is in place, you can use Selleys Direct Stick 700g Timber Flooring Adhesive Sausage to glue the hardwood flooring down.

Let me know if you have any further questions.

Jacob