# Dry Pack for laying porcelain tile on exterior patio



## Kyong (Sep 4, 2015)

Hi everyone,

-I am new to Contractor Talk. I read the posts and find them to be very insightful and that is why I decided to join.

THE PROJECT'S BACKGROUND
-The project that I am working on is the construction of a patio that is about 20 x 25 ft. The project is being carried out in Toronto-Canada where we experience sub zero temperatures in winter. The soil also freezes during that time.
- It was initially planned to lay pavers on the patio. That would include digging and putting a 4 to 6 inch gravel base by compacting crushed stones (mix of stone and screening). Then I would have laid over the gravel base a layer of 1-1/2" of screening (sand) as a bed for the paving stones.

-THE PROBLEM
The project took another direction when the customer wanted to have porcelain tiles laid instead of pavers.

- THE QUESTION: I am still going to keep the compacted gravel base to have a solid foundation for the patio but instead of laying a plain layer of screening/sand over the gravel base, will laying a "dry pack" (a mixture of 3 parts sand and 1 part Portland cement with some water added to it to make it sticky enough just to make a ball with the hand) provide a good support for laying the porcelain tile?

- THE CONCERN: I have seen people laying tiles on dry pack on YouTtube but that was for interior floorings. Does anyone have any insight about laying porcelain tile on dry pack on a patio that will undergo the harsh winter condition? 

- If the dry pack method of installing porcelain tile is not appropriate for exterior project that are subject to winter conditions, what are the other solutions?

- Thanks a lot for your help.

Kyong


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## AGullion (Apr 19, 2015)

Yes i do. You are insane if you do it . furthermore , that's not a mudbed scenario, that's a concrete job . And if you jump on a lot of flat, exterior tile work , expect problems ....just look around ...nearly all exterior tile work has issues , period . the best thing about your area is it gets cold and stays that way ...that's better than a lot of freeze thaw cycles . I'd recommend stamped concrete and walk away.


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## AGullion (Apr 19, 2015)

Not trying to be sarcastic or discouraging, but jobs like that can bite you hard later .


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## Kyong (Sep 4, 2015)

Hi AGullion,

Thanks a lot for taking the time to respond to my questions and concerns.
I am going for the concrete method and the "Stamped concrete" idea seems idea.
This might be more expensive but in the long term it might be well worth it.
Kyong


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## AGullion (Apr 19, 2015)

If you absolutely have to lay tile on horizontal work outdoors, I ve had pretty good luck with Schluter ditra . it seems to make it more freeze thaw stable....., and Schluter knows that, but they don't market it ..exterior work had so much liability due to the high failure rate.


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## Kyong (Sep 4, 2015)

Hi,

1. If I go with Schluter Ditra as you mentioned, I will still need to pour a reinforced concrete slab underneath so as to have a solid and stable substrate. Right?

2. For the Schluter Ditra, will I need to bond it to the concrete slab using a kind of modified thinset before installing the pocelain tiles on it?

Thanks


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## AGullion (Apr 19, 2015)

Yes.


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## MIKE ANTONETTI (Jul 17, 2012)

Don't even think about it, Stamped concrete all day long, one big solid piece, not like an overlay which will actually peel around edges etc. something of the slate appearance would be nice, and helps for slip resistance.

The mud bed on a paver base is ridiculous.


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## AGullion (Apr 19, 2015)

All seasoned tilesetters avoid large exterior jobs as a rule . They know the high cost of tile rework .


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## drbizerk (Mar 22, 2018)

I’m doing a big outdoor patio currently with porcelain pavers 24”x24”x3/4”. This patio is about 700 sq ft. I’ve excavated, flattened to grade for water run off, compacted a 2” layer of crushed stone into soil and flattened, non woven landscaping fabric over lapped 1 ft, 1/2” layer of fill sand pack and screed and flattened and leveled...next step is to install EZ Paver Panels on top of the sand followed by the porcelain pavers. The panels are supposed to replace the gravel bed as well as distribute the load of foot traffic. 
To make a short story really long....depending on the thickness and the weight of your porcelain you might look into the EZ Paver panels.


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