permaculture

["Gaden@ziplip.com" <Gaden@ziplip.com>]

Re: Ingrid's - Construction of garden retaining wall from broken patio 
concrete.


Had you considered using a rock-making technique instead of staining? This 
isn't intended to be detailed instructions but an overview.

You break up your concrete into managable chunks. Place them onsite in a 
rough shape of the desired result. Add any other building rubble like brick 
pieces, empty bottles etc. to fill in the gaps. Less gaps, less concrete 
needed. 

Handfulls of concrete mix used to roughly bond the chunky bits together. 
Chicken wire is moulded over the aggregate to a rock-like shape (or cliff, or 
waterfall, or cave, or boulder shapes). The wire moulding is firmly wired or 
twisted under some of the rubble.

A dryish high sand concrete mix is slapped over the mesh and worked into the 
shape. Old paintbrushes, files etc (any firm edge really) is then used to 
carve/shape into natural rock finish. Creative license to hack and smooth 
into natural appearing imperfect forms.

Final stage is the use of coarse sand and cement pigments to age-stain and 
finish the surface of the project. There is quite a range of powdered cement 
pigments available. It depends on what you want the final 'rock' to look like 
- weathered light sandstone, dark mossy granite etc. The powdered pigments 
are basicly flung onto the still moist concrete in random patterns and shadow 
lines to approximate the look of moss, algae, lichens etc. The old paintbrush 
is used to smooth in the colours together as desired.

Hope I've explained that okay. It is a cheap useful method for using up old 
rubble, and other collected junk such as bottles etc. It is surprisingly easy 
to get a good result. And you can be as detailed and creative as you wish. In 
a sense, the rougher you are, the more natural looking the finish. Makes a 
good family project as it is chunky and hard to muck it up.

There are several good videos on this topic that give you good step by step 
instructions. Afterwards, you can use the yoghurt method for encouraging the 
natural growth of lichens etc. Or if moist enough, mosses.