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Interior vs exterior waterproofing

MikeMac1234 | Posted in General Questions on

I have a 1970’s raised ranch and have a renovation in my basement started.  I have some effervescent and damp areas in the corner.  

Most Waterproofing contractors recommend interior French drain. They say disturbing the dirt is a mistake . Is this the best way to approach this project or is exterior  waterproofing a better investment?

Thanks in advance for your advise!

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  1. Patrick_OSullivan | | #1

    There are a couple things at play. On the cynical side of things, most basement waterproofing contractors are not masonry or excavating companies and are much more comfortable tackling the problems from the inside. That may be sufficient. If you have overhangs, gutters, etc., you can probably keep bulk water far enough away from the foundation such that an interior system is sufficient.

    I've also had experienced masons (who have no qualms excavating an entire foundation from the outside) suggest that it's worth tackling from the inside first. Really, it comes down to site conditions. Drainage, grade, water table, etc.

    If you are finishing the space, I like a design where there is a drainage path behind the finished walls. This could be dimple mat or something like Insofast ( directing water to the interior drain.

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