THE NEW FRAME
After investigating replacement options, owners Pleun and Anna decided it would be easier to go the tunnel-house route rather than trying to replicate the ancient steel-work and glass, but to fit the foundations, it would have to be a one-off design to fit the existing dimensions.
Pleun used his design experience to come up with a set of curved frames made from pairs of plywood strips held apart by wooden-block spacers. Two curves were used, one for coming off the waist-high southern wall, the other for coming off the lower northern one.
The couple created both shapes on their workshop floor, built jigs, then went into production mode, turning out sixteen perfect, painted pairs of graceful, lightweight arches.
Pleun’s background in fine furnituremaking was also useful when it came to creating out a wedge-tightened joint so that the long ridge could be assembled from shorter, more manageable lengths of timber. Watching these joints go together was poetry in motion and they are so beautiful, it would have been a sacrilege to cover them up.
At even spaces along the ridge, sixteen pairs of angled wooden blocks were preattached, ready to accept the ends of the plywood frames. Four screws at the top, four at the bottom and bingo, another frame held firmly in place. The initial ridge-and-frame assembly took three people about half a day.
matter to insert a metal pole through the centre of the roll, run a rope over each pulley and down to each end of the pole, then hoist the lot up past the blocks and lower it into the recesses. Two people did it easily without having to leave the ground.
The leading edge was clamped between two short battens and pulled along with a piece of rope. The plastic unrolled almost perfectly and pulled so smoothly, despite it being very long, that there was no need for a windlass even though the carefullychosen day was. Windless, that is.
The folds were shaken out either side and the structure was now covered. It was time to anchor the skin down and Redpaths also supplied a neat system for this called Duralock2. This is an aluminium U-channel which is preattached along the bottom timber, over which the plastic film falls. You can then work along (it’s better to work out each way from the centre so there’s less creepage) inserting a smaller plastic U-channel into the aluminium one, trapping the film between them in the process. A square plastic strip is pushed into the plastic U, spreading it and locking everything up tight. It’s an easy matter to remove the locking-strip one section at a time, re-adjust the plastic so you can pull out wrinkles, and then replace it. This gives you all the time in the world to get it perfect, without the incessant worry that the wind might get up and your lasting memory will be one of a translucent