For my workshop build I used ground screws
https://www.groundscrewcentre.co.uk/
They worked perfect for my 3 x 4 log cabin which was on a slight incline, 18 screws, combo of 500 & 750mm screws. They were relatively easy to install with the money back ratchet installation tool. No mess and concrete was pretty much a no no given the location.
The key thing is that after a year since build and a fully loaded shop, table saw, band saw, workbenches etc it hasn.t shifted a mm. I cant comment on the ones posted on facebook as I don't have facebook.
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