Planning & Design
Important Note
When building composite walls of any significant height, it is of crucial importance to consult with an experienced engineer.
- Develop a precise plan for your Terraforce wall by analyzing your site, noting slopes, drainage and shape of wall.
- Measure the length and the vertical height to obtain the surface area and thus the number of units required.
- Remember that retaining walls require professional design and supervision input and must comply with local building regulations.
- Refer to Terraforce design and installation manual.
Please note: When building composite walls of any significant height, it is of crucial importance to consult with an experienced engineer. The law is very strict on these matters, with the NHBRC requirement stating that one can build a wall to a height of 1.2m without consulting an engineer, but as a general rule 1.5m for walls no steeper than 70º is also possible. Any steeper and especially load carrying walls must be designed by a qualified engineer, even if only 1.2m high.
Terraforce Design Guide & Book of Ideas

Please register here to access the Book of Ideas and the two-part Terraforce Design Guide, “Section 1 Gravity Retaining Walls”, and “Section 2 Reinforced Soil Retaining Structures”, respectively. Should you have any questions contact us on admin@terraforce.com.
QUESTIONNAIRES & SUBMISSION SHEETS FOR DESIGN ASSISTANCE
Firstly, decide what you want to achieve, possibly with a layout sketch and a cross-section drawing. If you are not sure how to proceed, these three Terraforce questionnaires for gravity, near vertical or terraced walls or submission sheets for gravity ot composite walls that can be submitted to the wall designer to start off the planning process.
If you need quick calculations for the initial stages of your site, please consult our Design table creator for single skin Terraforce interlocking retaining walls.
Use this interactive excel sheet to work out the design values – number of blocks, wall height and recommended set back – for most Terraforce mortarless block wall construction.