What is the maximum height I can build my decorative wall and/or retaining wall?

The maximum height is determined by the product. Please carefully consult the product page of the retaining wall you are interested in! The height of a retaining wall varies according to several criteria: the type of material used, the type of soil, the wall's slope, any additional loads above the wall, and several other factors. Depending on your project, you may need to consult with an engineer to ensure your project is compliant and safe.