Most visitors to the walled garden (in truth they’re customers, but we prefer visitor) comment on our greenhouses, and in particular their timber ‘exoskeletons’. In fact the purpose of these frames is not to strengthen the greenhouse, as everyone supposes, but to support boarding which, during winter, protects the greenhouses from flying debris and takes most of the force of the wind. 6-inch wide boards, 4-inch gaps, and the full 8ft (2.4m) height of the greenhouses : they’re fitted during October – as the Autumn Equinoxial storm season gets going), and removed in late March, after the Spring Equinox.
Although the boards amount to more than 50% coverage of the sides, the reduction in light is much less – only around 25% : winter greens continue grow well enough, and tender perennial herbs brought under cover for winter seem to prosper, too.
The framework and boards are of treated rough-sawn softwood, generic sizes found at every building materials supplier, inexpensive and easy to work with. So much so, that it is not cost-effective treat the timber with further preservative in order to prolong its life. It’s better value to simply replace any decaying timbers as and when needed.
The original exoskeletons went up during the months after the four greenhouses were erected – following the great January 2005 hurricane. So they’re now 12 years old, and apart from a few of the boards (which are susceptible to decay when stacked for summer-time storage) I’ve not yet had to replace any of the structural timbers. That’s a 50% longer life than D and I had allowed for! However, as all four were built the same year, they’re now all looking they’ll need replacing at the same time, which would not be a welcome addition to my workload!
Decay is most advanced in the exoskeleton for Greenhouse 2, so by replacing that this year, and then replacing one other structure each year, we should be able to permanently stagger the programme of replacement/renewal. I’ve also found a way to simplify the design to use less timber and make the frame easier to erect and dismantle – and to do so single-handedly. This means that, in future, I can replace individual timbers as and when needed, rather than replace entire structures at intervals of years (which is more likely to result in a structure failing in a storm the winter before I was due to replace it).
I wonder what preparations we’d make were we to live in, say, The British Virgin Islands? We wouldn’t have greenhouses, true, but we certainly would have a garden we’d want to protect. Uist may have extreme weather in a UK or even European context, and storms here can and do badly damage buildings and claim lives. But compared to the suffering wrought by Carribean hurricanes, we are very fortunate. We are fortunate also to have the means to prepare.