There are 3 main techniques when erecting portals:

1) The first is to erect the columns. Then assemble the roof in sections on the ground (typically 2 - 3 portal bays). Once the roof is assembled, it is then lifted into place, taking care to leave the lifting equipment in place until the connection at the knee is fully connected.

2) The second is to hinge the column bases to the ground/foundation. Attach the rafter and roofing then lift the centre and connect at the apex.

3) The final is to erect completed individual frames and assemble the roof in the air.