This is a span to deflection ratio of 872. Although there are
no current Standards for pre-fabricated post-tensioned stone
panels BS 8298 part three [1] suggests a limit of span/360,
for stone faced pre-cast concrete. On this basis the deflection
due to wind is therefore well within allowable limits. On the
other hand a similar beam using Stoke Hall would deflect
20.4 mm, span to deflection ratio of 147 and may therefore
need to be constructed using thicker stones in order to reduce
the deformation.