A vertical-axis wind turbine (VAWT), comprising: a turbine assembly comprising a plurality of blades coupled to a rotor assembly, a turbine assembly support tower on which said turbine assembly can be mounted for rotation with respect thereto, said tower being configured so that the blades of the turbine assembly extend generally in parallel to said support tower; first and second buttresses (49, 51) that are each configured to be coupled to said turbine assembly support tower at a proximal end, a distal end of each said buttress being configured for attachment to a respective buttress support so that each buttress is inclined at an angle relative to said support; the VAWT being characterised by: a first buttress support and a second buttress support for coupling to said first and second buttresses, respectively, said first and second buttress supports each comprising a buttress grillage (7, 9), each said buttress grillage (7, 9) including a support top plate to which respective distal ends of each buttress (49, 51) can be coupled; a tower support for coupling to said turbine assembly support tower, said tower support comprising a tower grillage that includes a tower top plate to which said support tower can be coupled; and means (53, 59, 61) for coupling each said buttress end to a respective support top plate and an end of said tower remote from said turbine assembly to said tower top plate, said coupling means being configured so that the orientation of each said buttress end and said tower with respect to respective top plates (67, 17) can be varied. a turbine assembly comprising a plurality of blades coupled to a rotor assembly, a turbine assembly support tower on which said turbine assembly can be mounted for rotation with respect thereto, said tower being configured so that the blades of the turbine assembly extend generally in parallel to said support tower; first and second buttresses (49, 51) that are each configured to be coupled to said turbine assembly support tower at a proximal end, a distal end of each said buttress being configured for attachment to a respective buttress support so that each buttress is inclined at an angle relative to said support; the VAWT being characterised by: a first buttress support and a second buttress support for coupling to said first and second buttresses, respectively, said first and second buttress supports each comprising a buttress grillage (7, 9), each said buttress grillage (7, 9) including a support top plate to which respective distal ends of each buttress (49, 51) can be coupled; a tower support for coupling to said turbine assembly support tower, said tower support comprising a tower grillage that includes a tower top plate to which said support tower can be coupled; and means (53, 59, 61) for coupling each said buttress end to a respective support top plate and an end of said tower remote from said turbine assembly to said tower top plate, said coupling means being configured so that the orientation of each said buttress end and said tower with respect to respective top plates (67, 17) can be varied. a first buttress support and a second buttress support for coupling to said first and second buttresses, respectively, said first and second buttress supports each comprising a buttress grillage (7, 9), each said buttress grillage (7, 9) including a support top plate to which respective distal ends of each buttress (49, 51) can be coupled; a tower support for coupling to said turbine assembly support tower, said tower support comprising a tower grillage that includes a tower top plate to which said support tower can be coupled; and means (53, 59, 61) for coupling each said buttress end to a respective support top plate and an end of said tower remote from said turbine assembly to said tower top plate, said coupling means being configured so that the orientation of each said buttress end and said tower with respect to respective top plates (67, 17) can be varied.