Projects here seem to have their own timing. What seem like frustrating delays at the time have an uncanny knack of turning out to be necessary pauses: intervals which allow for much better solutions to emerge. The geodome greenhouse has been no exception. With the groundwork complete by the middle of last summer, I was hoping to have it covered in time for winter. This wasn’t to be. My fault mostly. I wasn’t happy with the lack of solid UV resistance data and guarantees on clear PVC and went off to ferret out something more robust. Several lengthy explorations into such materials as ETFE and polycarbonate later, it was clear that robust was beyond budget-busting, so in the end I came full circle back to the PVC.
But during the delay, two things happened. One of the suppliers we were in contact with listed a new high transparency UV-treated PVC film. And Liam acquired a high-frequency PVC welder. I’m sure neither of these facts will mean much to many, but take it from me: the end result is just so much better than it would have been had neither of those two things happened.
The greenhouse cover is now almost complete!
The PVC chosen for the geodome greenhouse cover is made by Expafol and is their High Transparency UV-treated film at 650 microns thickness which is rated for a temperature range -20ºC to +60ºC and should have a resistance against UV damage of between 5-10 years. I plan to cover the dome with shade netting in summer, both to prolong the life of the PVC and to protect greenhouse plants from scorching.
The image above shows part of the fishpond in the foreground and two of the four groups of 4 x 90-litre aquaponics grow-tanks which will be fed by, and feed back to, the pond. Underneath the grow-tanks will be several layers of seedling trays and large 50-litre buckets (image below) for the various climbers to be trained up the geodome frame. The central growing bed will contain bananas and a mango tree, plus various tropical and sub-tropical plants, herbs and spices.
Previous posts about the greenhouse:
Niklas February 10, 2018
Really beautiful construction.
how did you connect PVC cover with each other and attach to greenhouse construction?
Quinta do Vale February 10, 2018 — Post author
A high frequency welding machine was used to weld the triangles of PVC together in sections. Then each section attached to the next section with velcro and to the greenhouse frame with straps and buckles. The whole thing was easily removable, allowing for sections to be opened up to increase airflow or for single sections to be replaced if some suffered more UV degradation than others. I just wish I’d thought to take it off the day of the fires …