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I been laying a lot of wet laid bluestone lately. I typically install 1" blue stone with a about 3/4" of mortar. I almost always butter the back of each stone with thin set before I lay it. If I don't do this I always seem to have problems getting the mortar to adhere to the store. I've seen guys do blue stone and have no issues.

My question is what is the correct mortar mixture for laying wet laid bluestone?
 

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Have Trowel, Do travel
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¾" bed? all the stone we lay HERE, has at least 2 - 4 " of a portland cement / sand bed,

My question is what is the correct mortar mixture for laying wet laid bluestone?
there is no correct, depends on what the Engineer asks for, location, etc.. HERE, we aim for 300/350 kg portland per cubic meter of mortar mix,
which is a 1 part 3 parts mix. I like using coarse sand too. And I have never buttered the backside, probably difference in the stones we use
 

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Have Trowel, Do travel
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I will add too that when we pour the joints, a few days after install, we use a 2 parts portland, 1 part finer sand.
 

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And I have never buttered the backside, probably difference in the stones we use
Over here what we call bluestone usually is sawn or natural cleft and with the smooth surface, it tends to break a standard bond because of thermal cycling. A Portland slurry works well to counter it. I feel like most of the bluestone available (all but premium or blue select) is garbage and I've gotten away from it over the last 10 years or so.
 

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Weld o bond the back, mortar usually type S. 1/2 bed joint, furrowed uniformly beat down with a rubber mallet.
 

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Most of our bluestone is 1 5/8" thermaled, with a sawn back. We generally set them in 1/2" TO 3/4" bedding mortar, typically 1 part portland to 3-4 parts mason sand, along with just enough lime to control bleeding. Also, a little bonding agent in the mix. We also use a portland slurry, or thinset back butter, to the backs of the stone, depends on the mood.......
 

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Been experimenting lately. For large bluestone projects I steer people away from wet jobs and set in compacted 1/4"stone and use polymeric in the joints.
For steps (about the only time I mud bluestone) I run the 4" grinder on the back and score some shallow kerfs in. Then set using Stone Veneer Mortar.
 

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Bluestone seems to be so inconsistent and unreliable. Whether it starts peeling apart or has stains. I dunno just seems there are a lots of phone calls I get which lead to fixing or ripping apart a bluestone project
 

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Carl

Whats the main reason you been shying people away from wet laid stone flat work?
I am not sure of his exact reasons, but I agree with him and here is why.

Every wet laid patio I have taken apart had a failed bond and terribly cracked joints. Most of them weren't through any fault of the installer, just age. I think once the moisture can begin to get under the stone it isn't long before all hell breaks lose.

I spent some time with a hardscaping company and it was nice to be able to see how they do things compared to how masons typically do things and I honestly think that in my part of the country dry laid brick and stone is a better way to install than wet laid, provided the base is prepped right. It can be installed to be either permeable or not depending on the location and I think because the base is dynamic it is less susceptible to frost damage, and more easily fixed if it does occur.
 

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Custom Stone
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When I have to bond blue stone to horizontally to concrete or to cap a masonry wall, I use ardex-x32 and tuck point the joints with type-s. http://www.ardexamericas.com/en-us/Products/tilestone/Pages/X32.aspx This has always worked really well for me. Pressing thick stones in a setting slab works too but can get messy. Of course any of it is only as strong as the pour. This was put 16 years ago and nothing come loose. We get some foul winters here.
 

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Stone Guy
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Like Karl, I usually score the underside of the stone with an angle grinder first. Sponge it off, set it in type S. I've really never had flagstones pop up on me.....

I try to never set them in a mortar bed any deeper than 1"

I always try and wet-lay flag stone that are no thinner than 1"--often going with inch and a half. I feel like the thicker stone is less likely to come loose, so I use thicker stone.

I let the cement harden beneath the flag before doing the joint--and do the joints with rather dry mortar, pressed firmly into the joint.

My method has worked well for me....but then I rarely do wet-lay, having an extreme preference to dry lay flagstone.
 

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