Advance Northumberland requested that Tailor Engineering carry out specialist element design for a geogrid reinforced granular subbase, associated with the proposed development in Ellington, Northumberland. The design assumed a subgrade with CBR = 1.0 %, derived from plate bearing test, with an homogeneous subsoil/subgrade composed by a generic clayey material. The construction of the geosynthetic stabilised subbase used a well graded compacted granular fill (in accordance with UK Series 600 and 800 SHW, Specification for Highway Works). In this project, a multifunctional composite geogrid was selected for the subbase stabilisation.