Principal Core Information

Our 'Principal' core is constructed from selected finger-jointed softwood. Having a solid timber core, comprising narrow laminated slow grown spruce (eastern white pine, grey pine, or spruce) segmented with grain running in opposing directions that counter natural deflection, glued with Type 1 PVA adhesive, engineered for stability and maximum performance. Available in thickness 44 or 54 mm and sub-faced, achieving severe duty under the classification standard BS EN 12400:2002. The core’s density and surface finish mean there is no need for perimeter stile and rail framing, removing the potential for flexing or telegraphing often witnessed with stile and rail flaxboard core configurations. Available in FD30, FD60 and FD90. This core is a truly outstanding performer both mechanically and stability.


Plywood, Particleboard or MDF-faced door blanks in single-acting single door, single-acting double door and double-acting single door configurations have been mechanically tested at the laboratories of Chiltern Dynamics to DD171, EN947, EN 948, EN949, EN950, EN1191, and PAS 23 clause 6.3 All configurations achieved Severe Duty gradings to BS EN 1192 and DD171 Chiltern Dynamics assessment report Chilt/P06121 applies.

Having no need for perimeter stiles and rails the configuration is more stable in the long term providing a strong integrated core construction.

Our offer

Our experience in door manufacturing means that we are able to adapt, create and suggest door styles suitable for your project. We manufacture single or double doors, unequal pairs and flush over-panels. This extremely robust, solid laminated timber core is well suited to operating with integral closers, pivots and large apertures in high traffic areas. The nature of the assembly where timber strips are laid in opposing directions randomly selected not from the same log offer superior stability and endurance in a wide variety of environments.