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  1. #1
    Join Date
    Jan 2009
    Posts
    1

    Default Damp Proof VS Waterproofing

    Wet Basement Full Description:What is the black material on the outside of my foundation? How is it applied? Can I put it on the inside an unfinished basement? Where can I buy this stuff?
    What is the difference between damp proof and waterproofing foundation

  2. #2
    Join Date
    Aug 2007
    Location
    The Great White North
    Posts
    4,045

    Default Re: Damp Proof VS Waterproofing

    Depending ..... It's likely the black stuff on the exterior of your foundation is a modified asphalt base damp proof material and on the older homes it was rolled on. In many cases a similar material is still used today though many times it's sprayed on. This material is not intended to be used on the interior.

    The damp proof material does an adequate job of doing just that ..... providing a damp proof barrier to the foundation from moisture in the surrounding soil.

    However ..... if there is an excess amount of water and with the force of the surrounding soil creates a condition called hydrastatic pressure. Basically the pressure of this surrounding soil can exert enough pressure to force the water through into the concrete.

    Any imperfections from cracks or holes in the foundation will be the main source of water infiltration. The damp proofing material doesn't have any elasticity to bridge any imperfections.

    Water proofing is a method of employing elastomeric type of coating materials along with isolation or drainage membranes.

    The coating materials usually are a modified rubber material which cures to provide a elastic coating that stays flexiable and continious that bridges over the cracks and holes that exist in the foundation. In the event water comes in contact this will not be aborbed into the foundation.

    The second component is the isolation or drainage layer. There are many different materials and methods used for this as well. They can range from 6 mil poly .... rigid sheets of a fiber drainage board .... rigid foam insulation ..... and a product that I think is great is a dimpled semi-rigid plastic sheet.

    This is the important layer since it provides the isolation from the surrounding soil exerting the hydrastatic pressure forcing moisture into the foundation.

    This method of water proofing is very effective and far better than the standard applied black damp proofing material.

    In my opinion ..... the best method of water proofing the foundation is from the exterior since that's where the source of the water is from.


    Hopefully this makes sense and helps.
    Last edited by canuk; 01-10-2009 at 07:28 PM.
    "" an ounce of perception -- a pound of obscure "
    - Rush

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