Pyrite in Basement Appartment

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Posted by: from Saint Leonard
4/17/2008 at 2:25:18 AM

Because of severe heaving and cracking of basement foundation, I tested for pyrite which results were positive. Wondering if anyone has advice on the best way to find a contractor or if anyone can recommend one. Also if anyone has advice on how much i'm looking at in terms of cost for about 1100sq ft.


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Date/Time4/18/2008 at 10:24:01 PM

Hi Vince, We have extensive basement experience, both new and old, but I've never heard of the world Pyrite? Can you explain further. Thanks


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Jesse in Saint Leonard
Date/Time4/19/2008 at 12:20:59 PM

hi Joe, I'll just give you a quick history about it first. Pyrite is a mineral commonly known as "fools gold." Back in the mid 60's montreal was digging its subway network and the rocks and stones were then used as backfill for construction of new homes and buildings. Now what happens over time is that pyrite oxidises and procduces sulfuric acid. The acid then reacts with calcium carbonates and forms gypsum whose crystallization will cause stone to burst and backfill to swell and concrete to crumble. It actually is a very slow process and takes years for damage to appear. Its why it took until mid 90's for the city of montreal to notice that it wasn't isolated incidents. So levels of severity varies, but in my case the swelling has caused a 3ft round speed bump in my basement wooden floor. So basically the concrete slap has to be broken and the backfill has to be excavated and refilled with non pyrite backfill. So we are looking at extensive work and repair. Hope this helps

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Abba's Service in Huntsville
Date/Time6/11/2008 at 7:52:51 PM

I am sorry but I get a chuckle when a contractor with a logo say's construction on it doesn't know what pyrite is. Not to say bad things but Are you trying to hurt your business or what! If anybody should know what this stuff is it should be a construction guy! I am a renovation's guy and we do do Quality work but I am sorry we don't do that type of work I just wanted to laugh.

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