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Moisture migration – old building rehab

Robert_Williamson | Posted in General Questions on

Hello everyone;

So, I am currently trying to retrofit an old house given my grandparents. The biggest problem I have is with rising damp and damp slab, due to the absence of any capillary brak. 

I am thinking of dealing with the damp slab by applying a dimple mat over it or Schluter Ditra. On top of that the finishing layers. 

My question is: By placing a vapour barrier over the concrete slab I am encouraging the moisture migration towards its periphery? where it can make the humidity problem in the walls even worse? 

Thank you in advance

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  1. Tyler Keniston | | #1

    Is this a basement?
    Are there already finished walls?

    You may find this article helpful:,%20No%20Mold%20Finished%20Basement_FHB169.pdf

    Note: you must address any 'bulk' water issues before finishing. Then you can address vapor drives and condensation issues.

  2. GBA Editor
    Brian Pontolilo | | #2

    Hi Robert.

    First, I agree with Tyler, before you do anything to the basement, take care of any leaks and bulk water intrusion, if there is any. Then, make a full plan that makes sense with your intended use of the space. Are you trying to finish the basement? Are you just wanting a dry floor to store things on? Are you trying to insulate for performance. This may make a difference in the most cost effective steps for you to take.

    1. Robert_Williamson | | #3

      Thank you for your answers!

      This particular room is partially in contact with the ground. There is no record of bulk water entering the room through the walls or slab. The walls are made of stone. Concrete slab. There will be no more walls. Just the perimeter walls.

      However, the paint is always peeling of the walls and the wood tiles (directly glued to the concrete) on the floor getting out because of the high moisture content.

      This room will serve as a spare bedroom in this future vacation house. I want to solve the paint and wood floor issue.

      Kind Regards,

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