[johnkeegan]

I'm sure if I searched the site that I'd find this answer but... Is there a specific type of mortar to use when laying bluestone over an existing concrete stoop? It's in a protected spot, enclosed on all but one side, but still "outside." Also, should I do any specific prep work to the slab (other than sweeping) before I go over it?

[TrickyDick]

I was going to ask the same question....I'm also doing a stone veneer. Any tips?

[4seasons]

probally typeS

[Greensmith]

How weird, I just got a bid today and this was included in my design. Just a protected porch with bluestone on it. I would appreciate any tips also...

[johnkeegan]

Also, what's the best way to cleanup the mortar/concrete "hazing" on the stones? Is it muriatic acid?

[johnkeegan]

...and is there something to add to the mortar joints between Pennsylvania patttern bluestone so that it matches the stone better? Same applies to other types of stone as well. Maybe the same stuff they use to colorize grout??

[TrickyDick]

Lot's of questions....not a lot of answers.

[4seasons]

I've never seen it done,but there are blue and gray powders out there for cultured stone(when it's being made) to ge t the colors. Maybe mix the two or they sell colored mortar . Probally have to go w/ dark gray.
yes the acid does cleanup.

[Lanelle]

We're switching from Type 'S' to Portland for flat work.
Muratic acid wash after to clean it all up.

We also recommend a sealer be applied.

[agla]

The key is to clean as you go with sponge and water. Then you just have a little grey film to wash of with acid. I did not do the wet lay, but heard enough marching orders to the crew, a lot of venting when it was not done, and have done my share of muriatic acid washing.

I can't remember the name of the primer they would use, it was C- some number or other. It was remarkably similar to elmer's glue in look and smell. They also bought dark mortar when they wanted dark mortar rather than adding tint themselves. It is quite available here, I expect that it is everywhere.

They'd lay bluestone on about an inch of mud. They'd join it severa days later.

[Island Time]

The problem I usually have when having to veneer an existing concrete landing, stoop, etc..., is the amount of clearance you have between the door sill and the existing concrete. It's never quite enough. I've found that the 'thinset' is a very good product for this application. It is very strong and allows a thinner layer of mortar without reducing the strength.

[Nathaniel Carr]

We have done a little bit of this work.

Our stone dealer reccomends a latex mortar. Do you have frost? We use Kera-bond & Kera-lastic. It is a thinset mortar. It is pricy but has a nice bit of flex. The flex helps when the bluestone expands in the heat.

We have found that pattern gauged thermal bluestone, works well. It costs more but you can set it a little easier, you won't have to lift the stone to pack a little more mortar, which is hard to do.

You should clean your stoop with a pressure washer if you can, the latex sticks well so you don't have to scrub with muriatic acid.

There are dozens of mortar colors you can mix in. Go to the local brick yard or concrete supplier. They will have it.

We grout with a ziplock bag with a hole cut in the corner. Then we use a pointing trowel to key it in. Then we wipe the edges with a spounge. We have not had to clean with acid. Last year a new guy from a tile background mixed the grout loose and threw it into the joints, then wiped. Messy but it worked.

I have heard of a "grout release" agent that you put on the stones so the grout cleans easier.

What are you going to use on the risers?

[John Palasek]

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On this job, (below) which is typical, we started by removing a concrete slab which was installed when the house was built.
We actually had a small amount of clearance below the door sweep and could possibly have used thinset, but this would have raised the stone too high on the threshold. Secondly, since this is a North side, there would be icing issues in the winter, so we demo'd the slab and poured a new one.

The slab is just fibermesh concrete and we set it up to be approx. 1.5 to 2-inches below our finished surface. We also rake the finish on the slab to give the mortar a solid "tooth".

We used a pre-colored mortar mix with a latex additive to go with the stone, (in this case, Rainbow Flagging), and we use that as both the bedding mortar and the grout so we don't have to contend with grey mortar peeking through a grout joint. One color throughout completely eliminates that problem.

We start with the stones by the door since that's the most critical area. We make sure that the stone surface rests beneath the door saddle and we establish our pitch and levels from there. After we set a couple of stones, we grout them by simply slapping some mortar into the joints and tapping the mortar down with the edge of the trowel. Then we scrape off the excess and wipe everything down with a damp sponge. One wipe on each clean side of the sponge, then rinse and repeat. If you don't rinse the sponge between wipings, you're just smearing mortar around.

Then we just keep repeating the same steps until we're done. When we're finished, we'll give everything a light rinse with some muriatic acid and that's that.

If you have a large area to do and you can't finish in one day, make sure that you end on clean joints. That is to say that you don't have mortar oozing out into your work area for tomorrow bacause that will cause problems with setting the next stones and you'll likely end up having to chip it all out. Why make more work than you need?
I like to first scrape away the edges vertically and remove any excess mortar from the next day's work area. Then later, when the mortar has stiffened a bit, I scrape a bit more on an angle reaching under the work we just completed to create a hollow spot under the edge of the work we've finished.
Then, when we resume work, the next batch of mortar will be under-lap the previous work and acts as a type of scarf joint so that the joint is less likely to crack and separate all the way down to the slab.

The main thing with any cement job is to keep moving, keep a wet edge whenever possible, and clean up as you go.







Hope this helps!


-JP

[VoodooChile]

jp,
Are the pavers in that picture dry-laid?

If so, how do you dealing with heaving at the joint between the pavers and Rainbow flagging during freeze/thaw cycles?

[John Palasek]

.


Yes, they're dry-laid and as far as freeze thaw is concerned, I've never had a problem with that. Long Island doesn't really get a deep or extended freeze, so it's really not an issue.

I see that you're in zone 4. Deep freezes are probably more of an issue for you. But don't forget that the whole purpose of dry-laid pavers is to move with the ground and not to remain completely stable. If we ever did get a bad freeze and they lifted, I'd simply wait until spring and arrive with a plate tamper and set them down again.


-JP