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Building the Downland Gridshell
 

A gridshell is a structure with the shape and strength of a double curvature shell, but made of a grid instead of a solid surface. The grid can be made of any kind of material steel, aluminium, or even cardboard tubes - but the Downland Gridshell is made of slender oak laths bent into shape.

To prepare the oak laths for use all defects were removed and the resulting pieces finger-jointed together into standard lengths of 20 feet (6m). Six of these pieces were then joined to form 120 foot (36m) laths.

The diagonal grid of laths was initially formed flat on top of a supporting scaffold. The edges of the grid were then lowered gradually, and the grid bent into shape, until the full shell was formed and secured to the edges of the timber platform above the basement.

The grid is actually a double layer, with two laths in each direction. This is necessary in order to combine the required degree of flexibility with sufficient cross section for strength.

A fifth layer triangulates the grid to increase its stiffness. The laths are connected at the nodes of the grid with a patented system of steel plates and bolts.

The Downland Gridshell is one of a very small number of gridshell structures in Britain, and its design and method of construction are unique. A very high degree of carpentry skill went into its fabrication, emulating but not imitating the traditional framed buildings at the Museum.

The workshop area enclosed by the gridshell is known as the Jerwood Gridshell Space to reflect the Jerwood Foundation's generous support of this unique building.

Further details and illustrations of the construction of the Downland Gridshell can be found on the Museum's website.