# Forum Home Renovation Landscaping, Gardening & Outdoors  Untreated Steel posts for a TP retaining wall

## mn1

Need to construct a terraced vegie garden on a steep slope. I was thinking about using untreated steel for the retaining posts instead of the usual gal. (TP Sleepers) Apart from being cheaper I can cut to length off a 6m piece  and I quite like the look. With the use of raw steel as edging, clearly, at 4-6mm the product lasts quite a while in the ground - I was wondering if anyone can share their experience regards longevity of raw steel posts if they have used blue instead of gal and had it in the ground for a while. My soil is sandy and well draining...Done plenty of these walls up to 1m in the past but always used hot dipped.

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## droog

There are types of steel that are suited to outdoor use as a feature, I cannot remember the name of it. 
The type of steel you are most likely to get for the post will corrode and flake badly unless protected. 
Buy gal posts and apply the finish you want, there are rust effect finishes that will not compromise the steel structure. Use the correct steel for the edging. 
Edit: The steel type is Corten

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