Exterior Slab With Slate

Jason Whipple

I have a job coming up soon to pour a new exterior slab and then install real slate tiles to it. It's an 8' x 10' exterior slab at an entry way.
Add: The slab will be elevated 6" from grade.

I've done a few walk ways in the past but I built them on a 3" to 4" bed of mortar with about 8" of compacted gravel under it.

What are some precautions or methods I should consider before pouring the slab. Should I allow for a 3" bed of mortar on top of the slab or should I install the slate on the slab like any other floor? Also, what is the best thin set I can use for exterior conditions?

Thanks guys!

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Jason E Whipple, General Manager
Historic House Restoration, Cincinnati, Ohio
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matymatt23

Wish I could help you on this one your far more advanced in it than I am. I have a question for you, with the market the way it is how have you been getting more clients?

Jason Whipple

Mostly repeat clients and referrals. I have added two new clients in the last few weeks and possibly one more (still working on it).

I took some good advise from a man named Sonny Lykos and made sure that I left all my customers feeling like they got more than what I promised and not being happy with anything but a WOW at the end of the job. Also, because of this, I get some of the best references I could ever hope for so when new business comes, they do the selling. It's working out very well.

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Jason E Whipple, General Manager
Historic House Restoration, Cincinnati, Ohio
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Bill_Vincent

Jason-- You can do it all with the slab, but make sure it's pitched, and use a membrane over it from the Noble Company called Noble-deck. It's kind of like Kerdi on steroids. Good stuff. It'll protect the tile from minor cracking in the slab.

http://www.noblecompany.com/Products....aspx#products

Third product down


As for thinset, Laticrete 317/ 333 additive, or Mapei Kerabond/ Keralastic additive

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http://www.creativeceramicandmarble.com

Jason Whipple

Thanks Bill!

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Jason E Whipple, General Manager
Historic House Restoration, Cincinnati, Ohio
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kevjob

Bill V is the man!

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Kevin
Basement Finishing Highlands Ranch Colorado
Littleton Colorado, Basement Remodeling
Kitchen Remodeling Denver

jarvis design

Hey guys,
I am assuming from your location that you are dealing with freeze/thaw cycles? What happens to a single layer membrane when water goes through the grout? I am considering doing my front deck with tile and am going to construct the deck with 2x8's, exterior grade plywood, and ditra XL (its a thicker version of original ditra) - new on the market. I would also use kerdi to waterproof the seams. Then tile/grout. The reason for the ditra is it allows moisture to escape and any freeze/thaw will be taken care of by the uncoupling of the ditra membrane

However, I am not going to say I am a pro at exterior tiling (yet)
Some of the things I am also going to have to address is the flashing against the wall and the front edge of the deck. I have enough other home projects on the go right now!! Probably do it next year once I have learned more!!

Bill_Vincent

How's it do that? I'd think the waffles would HOLD the water. The whole key to a successful outdoor installation is making sure it's properly pitched. Then a flat sheet membrane won't hold a drop. One other thing-- the Nobledeck is specifically made for exterior installations. Much as I like Ditra, I don't trust it outside for the reason i mentioned above, even though Schluter says it can be used for that purpose.

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"Whether you think you can, or you think you can't, you're probably right."

http://www.creativeceramicandmarble.com

jarvis design

I am going to try the ditra outside, I know they have done tests, etc., however, I have always been the type to prove something will work before selling it to my customers. I might have to get that deck done this year!!
As far as the waffles holding the water, With proper slope, the water will drain out of the channels - which is all part of the installation as you have to allow that moisture to escape at the front of the deck.

Jason Whipple

Well, I broke out the old slab yesterday and the new slab will have about a 3/4" pitch in 10'. With the concern for drainage, do you think it would be wise to apply the ridges of the thin set in the direction of the slop or am I over thinking things?

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Jason E Whipple, General Manager
Historic House Restoration, Cincinnati, Ohio
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OCRS

I did something similiar about 7 years ago up here in Ottawa. I used the thinset/additive combo BillV mentions

Not one crack anywhere and it's been exposed to rain, snow and freezing temperatures the whole time (very little roof overhang)

Bill_Vincent

The only thing I'm apprehensive about is the amount of pitch. Instad of 3/4", there should be closer to 2 1/2".

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"Whether you think you can, or you think you can't, you're probably right."

http://www.creativeceramicandmarble.com

DavidC

Curious how you came up with 2 1/2" Bill. I would have gone 1/8" per foot and pitched it 1 1/4".

FWIW, my knowledge of outdoor tile work would fit in a thimble as I have done, let me see, oh yeah, none. Just looking to fill another thimble.

Good Luck
Dave

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NickD1882

Another alternative for helping with cracks in the concrete slab is ECB membrane by NAC products. I have used their ECB anti-fracture membrane a few times and find it very reliable and easy to use. go to nacproducts.com if you are interested.

genecarp

bill went 1/4'' per ft, i like 1/8'' better unless there is a condition that requires some quick moving water.

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Bill_Vincent

There is. It's called overnight freezing.

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"Whether you think you can, or you think you can't, you're probably right."

http://www.creativeceramicandmarble.com

Whip

just beware If the watter enters into the slate and then freezes before it can escape it will flake and crack quick. Very quick. I always try to use a full bodied porcelain that looks like slate when ever i can talk the homeowner into it is is a lot safer for you and here in Ohio easier to shovel the snow off of.
As for what kind of mortar tec super flex is great and is the only tec product recommended for outdoor use. i also always spread the thin set in the direction of the slope. as for the pitch more is better at least 1/8 per foot but i do try to get a 1/4 if it would not be to noticeable. the idea here is to get the watter off before it has time to soak in and freeze. Good luck. I have done about 20 outdoor patios in slate and hated them all. word for the wise seal everything. I use mercrete hydrogaurd over the slab as a anti fracture and a waterproofing then set my tile. 3 coats of stone sealer and seal the grout.

Bill_Vincent

Actually, the spec says the MINIMUM is 1/4" per foot.

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"Whether you think you can, or you think you can't, you're probably right."

http://www.creativeceramicandmarble.com

Whip

bill you are correct specs do say 1/4in

R&D Tile

Just did this one with Flexbond and Flex guard membrane over a crack, we'll see how it lasts.

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