A knitted spacer fabric has a tightly knitted bottom layer, a more loosely knitted upper layer and linking fibres extending across the space between the lower and upper faces. Settable material, e.g. cement, is introduced into the space between the upper and lower faces and can be caused to set by the addition of a liquid, e.g. water. Until set, the fabric is flexible and can be shaped but after the material in space has set, the fabric is rigid and can be used as a structural element in a wide range of situations. The bottom layer has an extension that extends beyond the upper face and is connected to the upper face by elastic connecting fibres that draw the extension towards the other face, thereby at least partly closing the space at the edge of the cloth and preventing the settable material from spilling out. In addition, the packing of the settable material and maximum space between the faces are such that only a predetermined amount of liquid can be accommodated within the space and that amount is matched to the water required to set the cement.

A knit fabric having a modified knit structure comprising a first layer of jersey knit fabric and a second layer of jersey knit fabric, wherein the first and second layers of jersey knit fabric are joined to each other by a third layer of tuck stitches, and wherein the first and second jersey stitch layers include at least one continuous strand of bare rubber and a plurality of continuous strands selected from the group consisting of continuous strands of bare rubber and continuous strands of non-elastic yarn, and the third layer of tuck stitches are made of continuous strands of non-elastic yarn, knit together into the fabric so as to hold the first and second jersey stitch layers together.

Composite materials are described herein. An example composite material may comprise a shell fiber layer. The example composite material may comprise a membrane disposed adjacent the shell fiber layer.