One thing I see on a fairly regular basis in this forum is someone showing up with a preconceived desire to proceed with a faulty scheme, or one that is only partially "baked." I can't tell yet if this is what is coming. Elbow, why do you want to lower the grade around the back door and create more of a step? (Usually, people desire less steps rather than more so it would be good to explain the reasoning behind the desire.) In lowering the grade, it will become important to know how the grade outside of the project area interfaces with that which is within. Of course, we can't see ANY of that and it has not been explained to us. This is not a question about water which gets into the joints between pieces of stone. It's about the much greater volume of water that doesn't get in and must run off. In the last picture, what you are showing is what most of us would call some sort of "flagstone" ... relatively flat, broad pieces of irregular shape. My own thoughts about this is that thin flagstone does not really make good paving when installed on a sand base (regardless of whether there is concrete under it, or not.) If you walk on packed beach sand, you'll notice that your feet leave an imprint because the pressure of your foot is enough to cause a shift of unprotected sand. While flagstone protects the sand layer SOME, it is THIN and CAN shift in small degrees (usually in a rocking motion) when pressure is applied and depending on the state of moisture content in the sand base. It can shift due to the action of freezing and thawing. Over time, these small shifts can add up to a cattywampus and not very pretty surface ... not the kind of thing you'd want, really, for a rock solid 100-year old barn and nice house. Thin flagstone makes a much better -- durable even -- paving surface if it is mortared directly on top of a concrete slab ... without any sand embedment layer at all. But this kind of installation, while not impossible as a DIY project, requires some learning and skill so is usually left to someone already with experience. Using this size project to "learn" on might be asking a bit much of one's self. It would be MUCH easier -- much, much easier -- to install a normal thickness (2 3/8" or greater) regular paving unit on an aggregate base: bricks, concrete pavers, uniformly cut stones, etc., if that's the type of base one wishes and if their experience is limited. One would still need to learn something, but it is much easier to develop skill for that than it is to develop skills at mortaring in flat work. You could use steel mesh in a concrete slab, but it would be pointless in paving laid on sand. I'm going to guess that the appeal of the flagstone is that you have access to it at a reasonable price ... but the other end of the equation is that its installation will be expensive (even if only in your labor the amount of time you must put in to learn, and the risk-factor of a potential botch.) As far as water that penetrates into the soil or below the paving ... consider that the soil is basically an ALWAYS DAMP medium. That's why the grade outside of a building cannot be raised to too high an elevation. If the grade is too high, the only solution is reducing it. Also, the grade around a building must be graded such that water runs away from the building (it is usually said for 10', but it depends to some degree on surrounding conditions.) If the grade elevation around the building is acceptable, then there is no reason to worry about the soil having some dampness. It's the way it is. What one should worry about is moving the excess rain water the heck away from the house ASAP. In the case of this paving, if you get the surface to drain properly, there is nothing to be concerned about with a little water entering between paving stones. The idea that you can put down a slightly subsurface waterproofing membrane to take care of water penetrating the soil is more likely to cause problems than solve them. It's not needed. And you wouldn't want to create a layer of water that has no real route of escape.

Have you thought of acid washing your concrete first. I have seen some beutiful pictures but dont have experience. I wonder if anyone has done this to an old concrete patio. I thought I might try it before I spent the money on something to go over it.

Since you're wanting something that is cooler, I would first look at coatings made for pool decks. One brand is Kool Deck. A relative had this installed around her patio and pool and apparently it's supposed to be much cooler than bare concrete. Personally, I'd call some companies that specialize in coatings and review all your options. Here's one company I found that's in the East Bay.... their photos will give you some ideas. http://www.liquidcoatingdesigns.com/concrete-resurfacing-company-portfolio/porch-concrete-resurfacing-bay-area. Another option is stamp overlay, such as this . Also thought you might like seeing a nice photo of travertine. I had flagstone along the walkway of my previous home and you're correct about the surface being uneven. We had to be careful about the type flagstone we chose since we wanted as smooth a surface as possible. I can't say I found it any cooler than concrete with a SW exposure. I would have concerns about covering the edge of your stucco with a concrete step. Check the link below for info on stucco and the importance of drainage. Here is an excerpt from page 7: "Rain will soak into any stucco coating; the water will head downwards, and it must escape at the bottom. Weep screed lets water out through its perforations, and it stops the stucco from bonding to the cement foundation and creating a dam where water might pool. The screed should span between the wood framing or sheathing and the concrete foundation, and it should terminate at least 8 inches above grade". Here is a link that might be useful: Stucco

Thanks, everyone for your encouragement! I've posted more WIP photos to the link below. Slow - in answer to your question about the base, I'm drawing the design onto the concrete and attaching tile directly to it - no mesh beneath. I prep the surface with a slurry of that bonding treatment first. We get almost no precipitation here, so I haven't been too worried about ice heaves and such. (Earthquakes on the other hand...) Bamasusana - I love the idea of the stepping stones in pea gravel. Please don't be surprised if I steal it. Dena - I completely agree with you that the circles would "pop" a lot more if I'd gone with just one color. However, I went with the (more fraidy-cat) approach of random colored tiles because I guess I'm pretty critical of what I've done so far and didn't necessarily want the circles to pop. Instead I was hoping for an effect more like one of those 3D paintings, where you have to let your eyes relax first before you can actually see the design. I also felt the various circles were too non-sequitur amongst themselves, so I hoped the random colors in between would emphasize the 'mis-matchedness' of the circles. (Ha - I'm pretty sure I'm overthinking this; that's the danger of having a software nerd do crafts around her house. :) ) Anyway, you have all made me feel good about my project. I do learn so much from the many talented contributors to this forum. Thanks so much again. I'll keep you all posted. Best, Myles Here is a link that might be useful: Project as of June 07