The glass box extension has a steel frame which sits on (60x30mm) solid bar steel columns composite with with the double glazing edge detailing and the 125x75mm Douglas Fir mullions to the side elevation. The columns act in pure compression whilst lateral loads are dealt with by rigidly attaching the roof plane to the new portal frame in the main house rear wall. The structural engineering of the scheme was further challenged by the need for a soffit recess to the ceiling perimeter, requiring a bespoke lapped plate moment connection.
bespoke structure in steel glass and timber
for the stair we devised discrete keyed mild steel shear pegs recessed to the timber stair treads
the tapering stair stringer continuous over is designed as a slim-line plate girder with flush surfaces, also incorporating the glazing support channel to the frameless glass balustrade
stair and landing structural component drawing