|A stepping stone made from beautiful rocks collected from rivers and lakeshores on the south island of New Zealand|
|My stepping stone workshop in Glenorchy, New Zealand|
|Gold and Black alternating bands of Mexican Beach Pebbles in Los Angeles|
|Reed College ? Mosaic|
What I do now is tell people that if they want to try to build a pebble mosaic that they should start with a simple stepping stone. I have built a number of them for a project as part of a trade I am doing with a man who is slowly fabricating wonderful steel structures for my garden. I made 26 18x18" square mosaics for his garden in a simple box made of 2x4's and a square sheet of plywood screwed together with a cordless drill and 2 1/2 inch long screws. The box has two longer pieces of 2x4 on two sides so that I can unscrew the box and tap the boards free after the step stone has cured, which takes about two or three days. I use a framing square to make sure the angles are 90 degrees, and drill shorter screws through the 2x4's in to the plywood to give it rigidity. If you want rounded corners or curves in your shape, I like to use the rolled flexible lawn edging that is normally used between grass and planting beds. This can be used inside the wood form with some blocking if you need it to maintain the desired shape.
|Wood form, lawn edging and beach rock mosaic|
|Bagged Pebbles at a stone yard in Seattle|
|Montana Rainbow Mix Pebbles|
|Carnaval Mosaic Panels|
An 18x18 inch mosaic that is 3 1/2 inches thick is very heavy and takes two people to move. I like to insert two pieces of 3/8th or 1/2 inch rebar in to the mortar for reinforcement because it sucks when a stepping stone you spent so much time on breaks when you take it out of the form. You can get these already cut at Home Depot, or cut them to length with a hack saw. It takes about 1 and 1/3 80 pound bags of Type S Mortar to fill a box of this size. One bag should work on a 14 x 14 inch step stone and it will be easier to move when it is done. Adjust the quantity if you use 60 pound bags. Do not use concrete mix! It dries out very fast and the stones wont stick. It has to be mortar, which is usually used to set stone or lay bricks. You will need another pieces of plywood a little bigger than the form to lay on top and step on to flatten the work once it is done. The tools needed are pretty low tech.
|Mixing Mortar in a wheel barrow with a hoe|
|A form in place made of flexible lawn edging supported by large 10 inch nails at regular intervals. The base is compacted crushed gravel|
|Mocking up a potential mosaic design with assorted stones collected from Puget Sound beaches|
|Finishing a stepstone at the O'Byrne Garden in|
The pebbles should be fit tightly together, considering their composition and placement. If I am doing a design with lines, I will set up the lines first after I have done the border, and then fill in the outlined spaces with carefully selected stones. On a cool day you can work for as much as 45 minutes before the mortar is too dry to work with. A 5 gallon bucket with some water in it is great for wetting individual stones and for rinsing your gloves if they get covered with mortar.
|Lotus Stepstones and Wood Form|
When you feel like it is flat and presentable and washed to properly expose the finished work, just let it sit for a few days to cure, getting it wet from time to time so that it does so slowly. Then you can unscrew the form and take a screw driver to scrape off the slaggy mortar edge along where the forms were. A well done mosaic doesn't show much mortar, just the lovely pebbles you so painstakingly selected. It might be a pain to do this kind of work, but I have been doing it for many years, and I think it is one of the loveliest forms of pavement imaginable. You could make a series of pavers and then put them together to make a pad, or space them and make a path. If you are ambitious, you can do mosaic work all over your garden. If you do them in place you don't have to move it in to place. If you do this you should put drop cloths over plants and walls as the mortar splatters some when hosing the work off. You will get better at it as you gain experience. After the mosaic has cured for about 25 days you can clean it with Muriatic Acid diluted with 4 parts water. Pour it on and scrub with a nylon bristle brush. It will remove any dulling mortar film left on the pebbles. Be careful using this stuff. Wear rubber gloves and cover your skin, and do not breath the fumes. You can buy it at the local hardware store. Use a flathead screw driver to trim out any unwanted globs of mortar and to smooth the joints.
|Lotus Step Stone Path in Portland, Oregon|
Paths made with 14x14" step stones make a lovely small path. One set I built are lotus blossoms, alluding to a Buddhist Jataka Tale about Sidhartha Gautama being born, and having lotus blossoms spring from his footprints. Another is simple alternating bands of black and gold Mexican Beach Pebbles.
If you precompose the design you are probably going to make a better stepping stone so I cannot emphasize enough the benefit of knowing what you are about to create. Fit the pebbles tightly together and try to be the best artist you can.
|Hand selected beach stones fit in to gaps in a mortar set stone parking strip pad|
|Simple bands of colored pebbles in round stepping stones match the mosaic path of a rattle snake between my two houses. The smaller rounds were made in the bottom of a 5 gallon bucket.|
I am currently working on a multi year project on the South Island of New Zealand which will include possibly hundreds of pebble mosaic stepping stones. One of the project's emphasis is the reduction of waste so I am incorporating lots of debris from the site in to the bases of the stepping stones as a way to remove it from the waste stream and act as reinforcement. This has to be carefully done so as not to block the insertion of the stones in to the mortar, but it is a great way to get rid of all kinds of bits of non biodegradable garbage!
|Debris collected from the work site|
|Debris added to the base of the stepping stone along with rebar for reinforcement|
|The finished stepping stone|
|3 Round Medallion mosaics mounted in a fountain wall, Portland|
|Plants encroach on 'The River of Life', an early in situ mosaic in my career|
|Round step stone with marbles, Indonesian Turquoise, Red Montana Rainbow, Black Mexican Beach and center beach stone|