Case Study: Grain Store for Luddon

2nd April 2020



The CWP team were tasked with designing, manufacturing and constructing the pre-stressed and precast concrete element of a 200,000 square foot commercial grain store building for Luddon Construction Ltd. 


The building consisted of a steel portal frame 8.5m to the eves which was cladded externally with our 180mm pre-stressed walling panels. Internally we created 6 storage bunkers (cells) and in addition we designed 6 bespoke precast escape tunnels that would provide escape routes for all personnel in the case of an emergency. The escape tunnels were 60m in length and provided 2 hour fire rated zones that would aid in the safe evacuation of personnel in the event of an emergency.



High volume storage for free-flowing grain material stored in bunkers surcharged to a height of 5.2m
Storing material with a bulk density of 890 kg/m3
With standing impacts and forces of a CAT 966 wheeled loader
Pre-stressed concrete with an XS1 exposure class (Coastal environment)
Fire rated to 2 hours for all load bearing structures
Food grade compliant mastic finish
To meet the design specification the building was cladded with CWP prestressed 180mm panels up to the height of 5.5m.

Each individual bunker used the perimeter wall and the face of the escape tunnels to provide grain storage bunkers that were 5.5m high and stored material of up to 5.2m high.


The above photo shows the escape tunnel meeting perimeter wall and the corner of one of the cells, the tunnel structure runs from the central passage of the store to the outside of the building.

To assist further with fire protection within the building a mid partition wall split the building in two on the central grid line, providing compartmental division to the structure. Each side of the internal spanning steel was clad with 180mm panel units to 5.5m high and then intumescent fire boarding was fitted up to the eaves, the pre stressed panels encasing the steel structure provides up to 120 minutes of fire protection which was key to the clients specification for protection of the employees and product.


When construction was complete, the vertical and horizontal joint detail was filled with foam backing rods and then sealed with high quality food safe mastic inline with the food preparation and storage regulations.


In total, 1150 180mm Pre-stressed units and 6 bespoke Pre-cast tunnels including sloping roof caps were designed, manufactured and supplied ahead of programme with no quality defects.

CWP received a thank you email form the main contractor commending us for helping to deliver the project ahead of time for their client.