Split Cultured Stone

6stringmason

Anyone have any idea what would make cultured split down the middle. I did a chimney and when the home owner went to nail the cap on he said he used 8 pennies and each corner split right down the middle. all the stones all the way down. I've never seen or heard of anything like that and was wonder what some of you thought. I'm going to go take some pics in a few days when I've got some time and I will post them.

bergenbldr

Is this a wood framed chimmey,sounds like a framing problem,also is there a foundation under chimney or is this a cantilevered platform.

lukachuki

All I can say is ouch! I'd like to see some pics.

Tim

6stringmason

Ok here is a pic of the chimney. It is a wood framed chimney with no support under other than the general framing. Meaning its a not a full masonry chimney. It is for a gas fireplace so there is just the normal 10" I think it was pipe for exhaust. Here is a picture before he put the cap on. I will post the other pics of the broken stone when I get time to get out there. Probably a day or two.

6stringmason

Ok guys. Here are the pictures I took this morning of the split stone. It wasnt pretty. Any guesses you have would be appreciated as I've never seen this since I've been doing this type of work. The owner said it happened when he was nailing the cap on with 8 pennies. He said it only did it to 3 corners and when I went up there he said now the 4th corner is doing it. Only hairline on the 4th though. This chimney is not even 1 yr old. I just want to make sure its not something I did wrong and to figure out what happened to help him get this taken car of. Thanks in advance for the help. And yes I know the stone are dirty but we didnt clean and seal them to I could get there to look at this and replace them.

bergenbldr

Still think has to do with a lack of proper framing support. I assume lath was nailed /wraped around corners. Either that or chimney installer was beating on inside with hammer.

jvcstone

appears to me that there has been some expansion of the underlayment. Is it possible that any moisture got in behind the stone?? Saw some real rock columns wrapped around cedar 4x4 split like that. The mason had not wrapped the cedar with felt paper, and back filled all of the void space. . What puzzels me is that it happened when the home owner nailed down the cap. Got to ask the obvious. Did he try to nail into the cultured stone? Some of that stuff doesn't have any strength to speak of. Or was that when it was first noticed, but had split earlier?
Your going to have to do some forensic investigation on this one.
JVC

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John VanCamp
www.jvcstoneworks.com

bergenbldr

Wonder if this might be due to edge swelling of osb. Most cultured stone ive seen is installed over plywood not osb .

Teetorbilt

I'm with jvc and bergen on the framing expansion. The stones may have already been in tension and the nails just gave the stones the start that they needed, like cutting a diamond.
The nailing of the cap and the cracks may also be unrelated, just coincidence. All corners doing the same thing goes back to the substrate.

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Mike Finley

If it was me I would be contacting the cultured stone manufacturer and quizing them.

6stringmason

Ok thanks for the help and suggestions guys. When I found out what happened I will let you know.

6stringmason

Well I brought these pics to the dealer that sold the stone. He said he's seen this many times. It's due to movement of the wood frame most of the time. Since masonry is a solid piece that has no give it cracks when the wood framing "dries up" or if it twists even an 1/8". Also when the wire mesh isnt wrapped around corners properly this can happen but I always overlap about 2-3 inches. Quite possibly the owner did it too when he hopped up there to nail in the 3/4" osb cap before the tin got put on.

One more possibility is the difference in extreme temperature in the cavity during winter when fireplace is on.

bergenbldr

Might also want to check if rafters were doubled under chimney,similar to skylight framing.

bergenbldr

In looking at the pics i noticed cap only extends flush to face of stone ,not 1to2 inches past face called for by owens corning instructions.Probaly not cause of spliting but may cause problem in future.