The streak of dry weather we’d been enjoying came to an end about the same time I was installing the first panel on the second side of the porch roof. I sank a screw and felt the first drops hit my face, then looked more closely at the first row of panels I’d installed. From my current vantage, the panels looked to meet at a jagged edge along the base of the roof. I’d need to re-do the whole row. My resigned sigh puffed out a cloud of vapor in air just above freezing, and the rain turned from a few tentative drops to a persistent fall.

The polycarbonate panels I’d chosen have much to recommend them–they’re durable, transmit a lot of light, and offer a good price-to-performance ratio, but as single-ply corrugated panels, they had enough flex to thwart my first attempt at a square installation. I might begin by firmly anchoring a panel along the edge of one rafter hold each panel in place with temporary braces at the bottom of the panel, but I still failed to keep the bottom edges of the panels aligned. It wasn’t too noticeable as I worked across the first side but became readily apparent when I switched sides and was able to look down across the peak of the roof to the edge below.

I made my way back to the side I thought I’d finished and started pulling screws, then pushing and pulling on the panels to tidy that bottom edge, losing a morning’s worth of work and growing wetter. Having achieved an edge I could live with, I made my way back over to the other side and picked up where I’d left off 5 re-hung panels ago. Six down and four to go, and the rain showed no signs of letting up. I’d learned from my mistake, and the second side went in without incident. In retrospect, it would have made sense to start on the less-visible side of the porch to keep my mistakes less visible, but the panels were up and I was only moderately hypothermic.