A timber frame, built from 4 x 2 inch pressure treated timber, is ideal for a polycarbonate greenhouse base, (though it could also be used as a base for a glass greenhouse)
The 4 x 2 timber is levelled, and secured to the ground by way of attaching it to wooden stakes that are hammered 2 feet into the ground.
The metal frame is then attached to the timber using angle brackets as shown here:
Following this the polycarbonate sheets are fitted to the metal frame
Importantly the bottom of the polycarbonate sheets are then "stitched" to the timber using heavy duty screws with rubber washers - this ensures the bottom of each sheet is well secured to the timber, meaning the wind cannot get under the bottom of the polycarbonate sheets
The result is a polycarbonate tunnel that is installed on a secure, level footing with the bottom of each sheet well stitched in place
