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Bluestone dry laid over slab

15211 Views 13 Replies 8 Participants Last post by  CJKarl
Hey guys,

I have a customer who wants bluestone (36"x24") wet laid for a walkway.

No staggered bond, just "stacked" 36x24, with a brick border. It's a straight run for about 20', then there are a few curves.

I am pouring the reinforced slab tomorrow. Due to the varying thicknesses of the stone, and specifically uneven/split bottoms, and the general concern with getting a good bond with bluestone, I am thinking about talking the customer into the following:

Dry laying the bluestone over the slab, and filling in joints with Gatordust. Then wet laying the brick soldier course for the border.


1) what do you think in general about this plan?
2) if I execute this plan, would it make sense to use Gatordust in the joints of the brick as well, for a uniform look? Or use mortar in the brick joints, Gatordust in the bluestone joints?

I appreciate any input on this!
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My fear is that because the brick are wet laid, the water which will seep through the surface has nowhere to really go, nowhere to escape. So after a rain, the sand base under the bluestones would be completely saturated and would remain saturated for quite some time. Is that a problem? The sand base also would have nowhere to go, so it's not as if the sand would be washed out. So the question becomes, is saturated trapped sand problematic? Would it heave like soil? Would it even matter if it heaved a little, since there is no mortar to crack?
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I think the gator dust throughout would look much better than different grouts.

Im not a masonry guy but my gut instinct is why wouldnt you just dry lay all of it? Especially if its getting a nice concrete pad.
I don't get it...bed it up or down with mortar. It's over a solid surface, it needs to be wet laid...there's no drainage.
I don't get it...bed it up or down with mortar. It's over a solid surface, it needs to be wet laid...there's no drainage.
Pavers are laid with stone dust as a bed over a concrete base all the time , and a soldier course set in mortar . Then poly sand in all the joints including the soldier course . Basically the same set up as the op explained . While I agree that there is little to no drainage the only thing keeping the water to a minimum is the use of the polymetric sand . I don't get it either but it's done like this all the time with good results .
Guys, I understand that there is no drainage, in fact I identified that as one of my primary concerns. What I'm wondering is ... does it really matter?? What is the worst that can happen if the sand remains saturated for several days after a rain storm?

I'm trying to avoid a wet installation because these stones are looking like a B*TCH to lay wet. Varying thicknesses, and some of them are "split", so that they are 1.5" in parts and 2.5" in parts. That, coupled with the inherant problems of bluestone adhesion, is what concerns me about wet laying these suckers.

Metro - I prefer to wet lay the brick borders so that I have a solid, permanent border, instead of installing plastic edging that I sometimes see on paver installations, which not only looks cheesy IMO but I also question it's integrity.
So sand getting wet and then freezing and heaving doesn't matter to you? Then do it.

My opinion is that if you have an impermeable non flexible base then you need impermeable non flexible joints...if you have a permeable flexible base you need a permeable flexible joint. Match the joint to the base...But it's your as you like
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this is how we kinda do it, we dry mix sand(0-3mm) with portland cement, and use that dry mix to lay the stone, but, on some jobs they ask how you explained.
but were the soldier coarse goes i usually leave some kinda drainage under, be it piping, tubing whatever.
i will plan the waters escape root before i pour the slab though,
i will explain better, the poured slab i can slope anywhere i want the water to go.
and where I end the slab, i will insert half way, them drenage tubes,Those flexible tubes with all the little holes around it, the diameter depending on the slab, but usually a couple 70mm tube will do. that leaves me with an inch or so of mortar under the soldier coarse
i keep the slab usually around 10 cm. (4 inches) under the finished height, considering the stones range from 1-2inches in height
either lay them all dry and anchor in some edging or do it all wet. mxing it the way you want is just backwards and a waste of time and money. to properly do it you will have to core out the crete to allow the bedding sand to drain,
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I'm totally aware that this is not a conventional method. My main concern is avoiding wet laying the bluestone, while wet laying the brick borders.

The reinforced slab is poured. I'm thinking I will put several weep holes in the brick mortar bed in the portion of the slab that everything is pitched towards. This will give the water an escape.

Frankly if the water has an out, I should be in good shape, yeah? The sand shouldn't remain waterlogged, as there will be plenty of pitch towards the weep holes.
I'm totally aware that this is not a conventional method. My main concern is avoiding wet laying the bluestone, while wet laying the brick borders.
Well, we wet lay only when for streets or for heavy traffic areas,
or else no need to wet lay.

foot traffic is done in the method you explained.
sometimes we don't pour concrete either
Why are you avoiding wet laying the blue stone?

In my mind that is the fastest way, especially with a batch of stones of varying thickness?

Throw down a thick bed of mud, get after it with deadblow hammer and a big straightedge and then clean the excess out of the joints.

Also, you can dry lay the brick easily enough, lay down your stone dry, cut your edges how you want and then make a notched board with a small level taped on and use that to screed out the trench for your soldier course, lay them a touch high, install edging and then tamp the brick.
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Bluestone is easily laid in mud.
Anyway, my only fear would be the wet sand freezing and pushing the brick outward.
What if you lay the brick with a 1/4" open head.
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