You have a bed that bakes at noon, a door that gets flayed by wind, or a corner where nothing will grow, and the natural answer is to build something solid — a full shade roof, a wall, a greenhouse. That is usually the wrong size. A micro-structure is a small, light build that does a full-size job with a fraction of the materials, because it reads the site before it spends a nail. This is the plain version of the temple's field guide: what the sun and wind actually do, and the three builds that work with them.
The problem, plainly
Most structures are built from a drawing, not from a site. The sun's path changes through the year — high and north of east in summer, low and to the south in winter — so a roof sized to shade the bed at noon in July is wrong in January, when the same bed needs every ray it can get. Wind fails the same way: a solid wall does not stop wind, it makes turbulence on the lee side, and what sits behind it gets whipped harder, not less. Build against those two forces and the structure fights the land it stands on.
What actually works
The field guide's method is two readings before any cutting. Read the sun's seasonal path, and the fix is a slatted or trellis roof pitched so the high summer sun is blocked while the low winter sun slips under — the same frame that cools the bed in August lets it warm in February. Run the long axis east–west for shade structures, which face the noon sun, and north–south for windbreaks that must let the low sun through. Read the prevailing wind — on this land it runs from the east and southeast through the warm months — and answer it with a permeable screen at 40–60% porosity: slats, netting, or a hedge. A screen slows the wind and drops its drying effect across 10 to 15 times its own height; a solid wall just makes turbulence. Three builds carry the practice: the seasonal shade frame — four corner posts, crossbars, and a removable slat roof that lifts off in winter so the frame becomes a trellis or cold-frame support; the windbreak screen — posts on the upwind edge with porous infill, placed 10 to 15 times the bed's height upwind, with gaps at ground level so cold air drains instead of pooling; and the south-facing lean-to — a single sloped roof, open on the sunny side, closed on the north, whose overhang of about half the wall height lets the low winter sun in and shades the high summer sun.
How to run it
- Watch one season before spending a nail. Note where the sun lands at each solstice, where the wind bites, and where water collects. The structure built after a year of watching is half the size and twice the use of the one built from a drawing.
- Give the structure one job: shade a bed, slow a wind, or warm a corner. One job per build.
- Match the build to the job — shade frame for a bed, windbreak for a door or tender row, lean-to for starts or a tool nook.
- Set the orientation before you cut: east–west for shade, upwind for the screen, south for the lean-to.
- Keep the joinery simple and re-dress it each season — slats off in winter, screen patched, posts re-set.
Where it fails
- Building from a drawing instead of a season of watching. The July-size roof is wrong by January.
- Making the windbreak a wall. Solid infill creates turbulence behind it; keep it 40–60% porous.
- Guessing the orientation. A shade frame run the wrong way faces the wrong sun, and a windbreak that blocks the low winter sun steals the light the bed needs.
- Sealing the windbreak to the ground. Cold air pools; leave gaps so it drains.
- Building once and never re-dressing. The whole trick of these structures is that slats come off and frames get re-purposed.
The short version
Read the sun and wind on your own site for a season before you build. Answer shade with a slatted roof pitched to the high summer sun, answer wind with a 40–60% porous screen placed upwind, and for winter warmth build a south-facing lean-to with an overhang about half the wall height. Keep the frame light, keep the joinery simple, and re-dress it each season. The structure that reads the site first is half the size and does the full job.
From the Passive Micro-Structures Field Guide
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