Can bluestone go bad?

18 years ago

I posted this on an old thread about thermal bluestone but figured it probably makes more sense to start a new thread.

We just had a thermal bluestone patio installed and the stone, after a few months, has weirdly begun to chip (spall?) on its own and turn colors, like black and rust brown. Is this normal for thermal bluestone? When we were house-hunting, we had seen two homes that had thermal bluestone patios and thought it looked so nice that we would install one ourselves at whatever house we ended up with. Both those homes were at least a few years old and their thermal bluestone pieces seemed to have weathered well, looking smooth and dark gray, almost like granite. When we got our thermal pieces, most of them weren't as dark and had more color variation (all still bluish, though) - not sure if that means anything. All we know is that after a few months, the surface of some of our thermal bluestones are pock-marked (revealing a rust-colored pebbly interior) when they were mostly smooth before - some even have a golf ball size chunk missing now - and some pieces have discolored, as you can see from the pictures below. The last picture shows the general color variation in a good section of the patio (you can see a few of the darker pieces that look like the ones we saw at the other houses - two on the left, one at the top and one long one on the right). Does anyone have any idea what could be causing the color changes and spalling? We're worried that these problems will get worse and that all the stones will turn black/brown and/or continue to spall. We didn't expect all these problems with thermal bluestone, especially for the extra money.

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jerseygirl67
Original Author

18 years ago

He has never seen these problems before with bluestone. He does think it's a bit strange that stone would do that. At first, he thought it was mold and washed it with a very light solution of muriatic acid, but that didn't really work. The spots faded a bit and then came right back. And he has no idea about what might be causing the spalling. I don't think he is BSing us - I know honest contractors are a rare breed, but I really do think he is one of them. He did order thermal bluestone at $8/sq ft, and all the pieces have definitely been through the thermal process. We're just not sure why a good number of them have the blackening and/or spalling problem, and if this is common with thermal bluestone or not. At our old home, we had a regular PA flagstone patio - wide color range with the clefts. None of the pieces in that patio ever changed colors or spalled, so we find this very odd.

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Comments (10)

craftbuilder
18 years ago
I have exactly the same problem with a large area thermal bluestone walkway...1-1/2" dry butted joints, After the first season some of the stones began spalling to a point where the whole top layer about 1/8" would eventually shed off over time. The resulting surface is smooth again, but looks discolored and stained. Other stones have lost their color and look washed out. I have tried different types of stone cleaning agents to regain some color but to no avail.

From my preliminary research on bluestone, i guess there are different density grades depending on the batch that was quarried. This combined with the freeze thaw cycles in the NE seem to be the possible culprit. The stone yards have no clue when I address this issue to them and they have no clue what type/quality of bluestone they are selling. So my multi thousand dollar walkway looks like crap and I have to see it several times a day. I don't know if replacing some of the stones is worth the time and money if this will only continue to happen again and I am not sure how to purchase/specify stone that is less likely for this to happen based on the lack of knowledge of most salesmen. If i had to do it over again, I would have used a bluestone-like concrete paver.

My contractor was also perplexed and was giving me the old "stone is a natural substance with imperfections" BS. After his 2 failed attempts at making the appearance acceptable (scraping and burnishing), he is still willing to work with me on this problem up to and including some stone replacement....but i need to know if there IS? a solution?
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magerm
10 years ago
Did you ever get a resolution to this problem? Did it get worse? We have the same problem with our patio in Bronxville NY
pinkie95
10 years ago
I have Asian Bluestone on my covered porch. This stuff started powdering up and flaking off within the first year! The rock dealer tried to tell me that I put "something" on it to make it do that! After a fight, we had them take out 90% and replace with new tiles. One year later, they are doing the same thing! I hate it. I want to rip it all out and put in concrete!
Saratoga Arnold
9 years ago
Did you find a solution or cause to the brown/discolored spots?
Ll Mm
7 years ago
Same with discoloration. Also Bronxville ny
Leo
6 years ago
Deicing salts on bluestone causes this too
riccardino
6 years ago
riccardino
6 years ago
We had a bluestone patio installed at our moms house in long island. This is one of the dpalling stones. I would say this is NOT Pennsylvania Bluestone but an inferior import. Ask your stone yard for the vendor or quarry where they get their material. These supply yards may be bringing in cheap material.
HU-8936040
3 years ago
I agree with riccardino but you have to realize natural stone is natural at the end of the day and im a 3rd generation Pennsylvania bluestone quarryman if it turned black whoch we call that black jack it had calcium deposit on it which we would never send to a customer but the brown means there is iron in the stone which we cant see when we produce the stone but i know most our buyers tell their customers to seal it to protect this from the minerals coming out and doing this.