[fjn]

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

:thumbsup:


These guys make some good stuff for the same application.

http://www.laticrete.com/architects/products/surface_preparation/thick_bed_mortars_screeds.aspx

 

[fjn]

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

I can definitely relate to what you said. Not sure of all the states "bluestone comes from however,the products sold here range from a pale green blue to a extremely dark, rich gunmetal blue that is close to black.

That blue / black stone is the stuff that I feel has the best durability.Some guys say it comes from up state New York. Does anyone have thoughts / ideas regarding this ?

 

[fjn]

I will take a stab at your question. First off,I get it that you need to match existing heights.My question,what is this 2.5-3" issue all about ? What is governing that height,existing concrete slab,soil etc.? Reason for asking,IMHO,I feel 2.5"-3" of any mortar is excessive.


The key to any flagging success hinges on several factors. They are base,drainage,substrate,joint size,and ability of stone to bond with the mortar. With that said, a type S mortar with a lime content a bit to the lower side of the scale (yes there is a range for all types) should do the trick both as a setting bed and joints between the stones.


There is a caveat to that though.You can enhance the bond with a slurry or score the backside with an angle grinder. However,the closest thing to a sure fire belt and suspenders approach is to sandblast the backsides with a course aggregate ,a mechanical bush hammer could be used but it is slower and you will break a bunch of stones trying.


After the back is roughed,either apply a portland slurry or a proprietary bonding agent (even to edges of joints) Keep joints to 1/2"or less,do not concave joint but flat join them.Doing so will not leave "troughs" to hold water.