Hi Sharon, Some differences between mortar and concrete: mortar is generally a mixture of "cement" (a specific type used for those applications) and sand whereas concrete is mixture of "cement" ( different type), sand and aggregate (think a variety of small stones maybe as large as 3/4" and smaller). Concrete is stronger for sure but I don’t think you are talking about an application where strength is the issue. I’ve enclosed the term “cement” in quotes because there are significant differences between different types of cement (see the Wikipedia URL listed below for a bit more information...it appears to be reasonably correct). For example, two main differences are “hydraulic cement” and “Portland cement”. Hydraulic cement doesn’t have as much early strength, sets up quite rapidly (lower working time - on the order of 5-15 minutes) but will harden underwater. Portland cement is the typical cement used in many industrial, commercial and home applications. It requires several hours to set up and won’t really develop full strength for approximately 30 days. So what? Some of the types of cement and specially mortars will have more lime (both calcium carbonate - not a problem - and calcium hydroxide - this could become a problem). I would stay away from using mortar since it is likely to create a bit higher pH if you’re not careful; I would use a general purpose Portland cement and mix it with sand to make your bonding material to fill in around the rocks. When laying the rocks and cementing them in place with your cement/sand mix I would do areas you can handle within the set up time...don’t try to do your whole pond at once. I would also recommend that you use as much stone as possible to reduce the amount of exposed cement. For example, you could use wider, flatter stones on the bottom surfaces or for vertical areas; you can build the equivalent of an underwater rock wall. After laying the stones and wiping out as much of the cement mix as possible wait a few days for it to set up. Then you will want to wash it down with an acid to help rinse it off the rock surfaces (this will help stabilize the pH later on). What to use for an acid wash??? This is where I am sure some folks may come out and start yelling that you are dealing with poison; you’re going to kill your fish, etc. I’d recommend muriatic acid. This is nothing more than a 10% solution of hydrochloric acid. If you go to a store selling masonry/stonework products you may see some so-called “environmentally friendly” stone-wash products but if you read the product label you will often find they contain hydrochloric acid. You could use vinegar (acetic acid)...it works, but very slowly and it may be necessary to apply it two or three times to get the same effect as muriatic acid. You’ll want to wear rubber gloves, safety glasses and rubber boots. I’d use a plastic garden sprayer to spray it on - the joints and the surface of the rocks (some of your limestone-containing rocks will foam a bit). Spray the rocks and using one of those plastic scrub brushes on a long handle quickly scrub the surfaces. Immediately rinse with water. And now the thing you must do: dump in baking soda (it may take many pounds so buy BIG bags) to neutralize all the liquid that is now sitting at the low point in your pond (hope your remembered to stopper off the drain!). Once you’ve neutralized it it’s safe to pump out of your pond ... you’ve converted all that acid to sodium chloride...it’s nothing more than a salt solution at this point and is no worse than running a water softener which periodically recharges and dumps the brine solution usually into a septic tank or sewer. You then reapply a solution of dissolved baking soda to the rocks and cement to make sure you’ve neutralized everything. At this point you can fill the pond. Check on the pH over the next couple of weeks and it shouldn’t jump much above 8.5 or so (make sure you buffer it to have plenty of alkalinity). I would move whatever plants you intend to have in there back before I put the fish in ... at this point you’ll dealing with all the typical problems of “new pond syndrome”. Hope some of this helps. ---David P.S. Sorry it took so long to respond but you know me...it's almost hibernation time! Here is a link that might be useful: Wikipedia write up on what is Cement

It's often hard to get the right mix and technique when using regular mortar to make is stick properly. The easiest way to get around this is to use fortified thinset mortar. Buy it in dry form with either the fortifier pre-added or use the kind that takes a liquid fortifier - do not use the pre-mixed kind in the plastic containers. Thinset has a kind of glue in it, in additon to the mortar. It's a little messier to work with and somewhat more expensive, but you will find that it will stick the lava rock on really well.

You need some contrast. If you go brownish this will loose it's potential for design edge. Dark gray looks amazing! With white trim/white garage & a new door in a really bright color. Go all the way, good luck :)

Two choices, no rock or a rock band around the base of the house. If you go with the rock band perimeter, keep it low. Resist temptation to use a lot of it. Looking at your home, my choice would be no rock. I like the simplicity. Plus, it will make the build process easier and cheaper. Spend the money on better windows and insulation.